diff --git a/components/EventCard.vue b/components/EventCard.vue
index cbf4c4d..b0345e7 100644
--- a/components/EventCard.vue
+++ b/components/EventCard.vue
@@ -1,5 +1,10 @@
 <template>
-	<section class="event">
+	<section class="event" v-if="event.deleted">
+		<p>
+			Error: Unexpected deleted event.
+		</p>
+	</section>
+	<section class="event" v-else>
 		<h3>{{ event.name }}</h3>
 		<p>{{ event.description ?? "No description provided" }}</p>
 		<p v-if="event.interested">
@@ -8,10 +13,10 @@
 		<p v-if="accountStore.valid">
 			<button
 				class="interested"
-				:class="{ active: accountStore.interestedIds.has(event.id) }"
-				@click="toggle(event.id, event.slots.map(slot => slot.id))"
+				:class="{ active: accountStore.interestedEventIds.has(event.id) }"
+				@click="toggle('event', event.id, event.slots.map(slot => slot.id))"
 			>
-				{{ accountStore.interestedIds.has(event.id) ? "✔ interested" : "🔔 interested?" }}
+				{{ accountStore.interestedEventIds.has(event.id) ? "✔ interested" : "🔔 interested?" }}
 			</button>
 		</p>
 
@@ -22,11 +27,11 @@
 				<button
 					v-if="accountStore.valid && event.slots.length > 1"
 					class="interested"
-					:disabled="accountStore.interestedIds.has(event.id)"
-					:class="{ active: accountStore.interestedIds.has(event.id) || accountStore.interestedIds.has(slot.id) }"
-					@click="toggle(slot.id)"
+					:disabled="accountStore.interestedEventIds.has(event.id)"
+					:class="{ active: accountStore.interestedEventIds.has(event.id) || accountStore.interestedEventSlotIds.has(slot.id) }"
+					@click="toggle('slot', slot.id)"
 				>
-					{{ accountStore.interestedIds.has(event.id) || accountStore.interestedIds.has(slot.id) ? "✔ interested" : "🔔 interested?" }}
+					{{ accountStore.interestedEventIds.has(event.id) || accountStore.interestedEventSlotIds.has(slot.id) ? "✔ interested" : "🔔 interested?" }}
 				</button>
 				<template v-if="slot.interested">
 					({{ slot.interested }} interested)
@@ -42,10 +47,10 @@
 
 <script lang="ts" setup>
 import { DateTime } from 'luxon';
-import type { ScheduleEvent } from '~/shared/types/schedule';
+import type { ApiScheduleEvent } from '~/shared/types/api';
 
 defineProps<{
-	event: ScheduleEvent
+	event: ApiScheduleEvent
 }>()
 
 const accountStore = useAccountStore();
@@ -56,8 +61,8 @@ function formatTime(time: string) {
 	return DateTime.fromISO(time, { zone: accountStore.activeTimezone, locale: "en-US" }).toFormat("yyyy-LL-dd HH:mm");
 }
 
-async function toggle(id: string, slotIds?: string[]) {
-	await accountStore.toggleInterestedId(id, slotIds);
+async function toggle(type: "event" | "slot", id: number, slotIds?: number[]) {
+	await accountStore.toggleInterestedId(type, id, slotIds);
 }
 </script>
 
diff --git a/components/EventsTable.vue b/components/EventsTable.vue
index ec66827..bd7d347 100644
--- a/components/EventsTable.vue
+++ b/components/EventsTable.vue
@@ -1,5 +1,8 @@
 <template>
-	<div>
+	<div v-if="schedule.deleted">
+		Error: Unexpected deleted schedule.
+	</div>
+	<div v-else>
 		<table>
 			<thead>
 				<tr>
@@ -14,7 +17,7 @@
 			<tbody>
 				<template v-if="edit">
 					<tr
-						v-for="event in events"
+						v-for="event in events.filter(e => !e.deleted)"
 						:key="event.id"
 						:class="{ removed: removed.has(event.id) }"
 					>
@@ -52,7 +55,7 @@
 								@click="delEvent(event.id)"
 							>Delete</button>
 							<button
-								v-if="changes.some(c => c.data.id === event.id)"
+								v-if="changes.some(c => c.id === event.id)"
 								type="button"
 								@click="revertEvent(event.id)"
 							>Revert</button>
@@ -95,7 +98,7 @@
 				</template>
 				<template v-else>
 					<tr
-						v-for="event in events"
+						v-for="event in events.filter(e => !e.deleted)"
 						:key="event.id"
 					>
 						<td>{{ event.id }}</td>
@@ -126,9 +129,9 @@
 </template>
 
 <script lang="ts" setup>
-import type { ChangeRecord, ScheduleEvent } from '~/shared/types/schedule';
-import { applyChangeArray } from '~/shared/utils/changes';
+import type { ApiSchedule, ApiScheduleEvent } from '~/shared/types/api';
 import { toId } from '~/shared/utils/functions';
+import { applyUpdatesToArray } from '~/shared/utils/update';
 
 defineProps<{
 	edit?: boolean,
@@ -137,18 +140,18 @@ defineProps<{
 const schedule = await useSchedule();
 const accountStore = useAccountStore();
 
-function canEdit(event: ScheduleEvent) {
-	return event.crew || accountStore.canEditPublic;
+function canEdit(event: ApiScheduleEvent) {
+	return !event.deleted && (event.crew || accountStore.canEditPublic);
 }
 
-const changes = ref<ChangeRecord<ScheduleEvent>[]>([]);
-const removed = computed(() => new Set(changes.value.filter(c => c.op === "del").map(c => c.data.id)));
+const changes = ref<ApiScheduleEvent[]>([]);
+const removed = computed(() => new Set(changes.value.filter(c => c.deleted).map(c => c.id)));
 function replaceChange(
-	change: ChangeRecord<ScheduleEvent>,
-	changes: ChangeRecord<ScheduleEvent>[],
+	change: ApiScheduleEvent,
+	changes: ApiScheduleEvent[],
 ) {
 	const index = changes.findIndex(item => (
-		item.op === change.op && item.data.id === change.data.id
+		item.deleted === change.deleted && item.id === change.id
 	));
 	const copy = [...changes];
 	if (index !== -1)
@@ -157,15 +160,15 @@ function replaceChange(
 		copy.push(change);
 	return copy;
 }
-function revertChange(id: string, changes: ChangeRecord<ScheduleEvent>[]) {
-	return changes.filter(change => change.data.id !== id);
+function revertChange(id: number, changes: ApiScheduleEvent[]) {
+	return changes.filter(change => change.id !== id);
 }
 
 const newEventName = ref("");
 const newEventDescription = ref("");
 const newEventPublic = ref(false);
 function editEvent(
-	event: ScheduleEvent,
+	event: Extract<ApiScheduleEvent, { deleted?: false }>,
 	edits: { name?: string, description?: string, crew?: boolean }
 ) {
 	const copy = { ...event };
@@ -178,21 +181,23 @@ function editEvent(
 	if (edits.crew !== undefined) {
 		copy.crew = edits.crew || undefined;
 	}
-	const change = { op: "set" as const, data: copy };
+	changes.value = replaceChange(copy, changes.value);
+}
+function delEvent(id: number) {
+	const change = { id, updatedAt: "", deleted: true as const };
 	changes.value = replaceChange(change, changes.value);
 }
-function delEvent(id: string) {
-	const change = { op: "del" as const, data: { id } };
-	changes.value = replaceChange(change, changes.value);
-}
-function revertEvent(id: string) {
+function revertEvent(id: number) {
 	changes.value = revertChange(id, changes.value);
 }
 function eventExists(name: string) {
-	const id = toId(name);
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
+	name = toId(name);
 	return (
-		schedule.value.events.some(e => e.id === id)
-		|| changes.value.some(c => c.data.id === id)
+		schedule.value.events?.some(e => !e.deleted && toId(e.name) === name)
+		|| changes.value.some(c => !c.deleted && c.name === name)
 	);
 }
 function newEvent() {
@@ -200,15 +205,17 @@ function newEvent() {
 		alert(`Event ${newEventName.value} already exists`);
 		return;
 	}
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
+	const id = Math.max(1, ...schedule.value.events?.map(e => e.id) ?? []) + 1;
 	const change = {
-		op: "set" as const,
-		data: {
-			id: toId(newEventName.value),
-			name: newEventName.value,
-			description: newEventDescription.value || undefined,
-			crew: !newEventPublic.value || undefined,
-			slots: [],
-		},
+		id,
+		updatedAt: "",
+		name: newEventName.value,
+		description: newEventDescription.value || undefined,
+		crew: !newEventPublic.value || undefined,
+		slots: [],
 	};
 	changes.value = replaceChange(change, changes.value);
 	newEventName.value = "";
@@ -219,7 +226,11 @@ async function saveEvents() {
 	try {
 		await $fetch("/api/schedule", {
 			method: "PATCH",
-			body: { events: changes.value },
+			body: {
+				id: 111,
+				updatedAt: "",
+				events: changes.value,
+			} satisfies ApiSchedule,
 		});
 		changes.value = [];
 	} catch (err: any) {
@@ -229,8 +240,11 @@ async function saveEvents() {
 }
 
 const events = computed(() => {
-	const data = [...schedule.value.events];
-	applyChangeArray(changes.value.filter(change => change.op === "set"), data);
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
+	const data = [...schedule.value.events ?? []];
+	applyUpdatesToArray(changes.value.filter(change => !change.deleted), data);
 	return data;
 });
 </script>
diff --git a/components/LocationsTable.vue b/components/LocationsTable.vue
index 58ec408..44e9c1a 100644
--- a/components/LocationsTable.vue
+++ b/components/LocationsTable.vue
@@ -11,7 +11,7 @@
 			</thead>
 			<tbody>
 				<tr
-					v-for="location in locations"
+					v-for="location in locations.filter(l => !l.deleted)"
 					:key="location.id"
 					:class="{ removed: removed.has(location.id) }"
 				>
@@ -38,7 +38,7 @@
 								@click="delLocation(location.id)"
 							>Remove</button>
 							<button
-								v-if="changes.some(c => c.data.id === location.id)"
+								v-if="changes.some(c => c.id === location.id)"
 								type="button"
 								@click="revertLocation(location.id)"
 							>Revert</button>
@@ -52,7 +52,7 @@
 				</tr>
 				<tr v-if='edit'>
 					<td>
-						{{ toId(newLocationName) }}
+						{{ newLocationId }}
 					</td>
 					<td>
 							<input
@@ -88,9 +88,9 @@
 </template>
 
 <script lang="ts" setup>
-import type { ChangeRecord, ScheduleLocation } from '~/shared/types/schedule';
-import { applyChangeArray } from '~/shared/utils/changes';
+import type { ApiSchedule, ApiScheduleLocation } from '~/shared/types/api';
 import { toId } from '~/shared/utils/functions';
+import { applyUpdatesToArray } from '~/shared/utils/update';
 
 defineProps<{
 	edit?: boolean
@@ -98,15 +98,15 @@ defineProps<{
 
 const schedule = await useSchedule();
 
-const changes = ref<ChangeRecord<ScheduleLocation>[]>([]);
-const removed = computed(() => new Set(changes.value.filter(c => c.op === "del").map(c => c.data.id)));
+const changes = ref<ApiScheduleLocation[]>([]);
+const removed = computed(() => new Set(changes.value.filter(c => c.deleted).map(c => c.id)));
 
 function replaceChange(
-	change: ChangeRecord<ScheduleLocation>,
-	changes: ChangeRecord<ScheduleLocation>[],
+	change: ApiScheduleLocation,
+	changes: ApiScheduleLocation[],
 ) {
 	const index = changes.findIndex(item => (
-		item.op === change.op && item.data.id === change.data.id
+		item.deleted === change.deleted && item.id === change.id
 	));
 	const copy = [...changes];
 	if (index !== -1)
@@ -115,29 +115,36 @@ function replaceChange(
 		copy.push(change);
 	return copy;
 }
-function revertChange(id: string, changes: ChangeRecord<ScheduleLocation>[]) {
-	return changes.filter(change => change.data.id !== id);
+function revertChange(id: number, changes: ApiScheduleLocation[]) {
+	return changes.filter(change => change.id !== id);
 }
 
 const newLocationName = ref("");
-function setLocation(location: ScheduleLocation) {
-	const change = { op: "set" as const, data: location };
+const newLocationId = computed(() => {
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
+	return Math.max(
+		1,
+		...schedule.value.locations?.map(l => l.id) ?? [],
+		...changes.value.map(c => c.id)
+	) + 1;
+});
+function setLocation(location: ApiScheduleLocation) {
+	changes.value = replaceChange(location, changes.value);
+}
+function delLocation(id: number) {
+	const change = { id, updatedAt: "", deleted: true as const };
 	changes.value = replaceChange(change, changes.value);
 }
-function delLocation(id: string) {
-	const change = { op: "del" as const, data: { id } };
-	changes.value = replaceChange(change, changes.value);
-}
-function revertLocation(id: string) {
+function revertLocation(id: number) {
 	changes.value = revertChange(id, changes.value);
 }
 function newLocation(name: string) {
 	const change = {
-		op: "set" as const,
-		data: {
-			id: toId(name),
-			name,
-		},
+		id: newLocationId.value,
+		updatedAt: "",
+		name,
 	};
 	changes.value = replaceChange(change, changes.value);
 }
@@ -145,7 +152,11 @@ async function saveLocations() {
 	try {
 		await $fetch("/api/schedule", {
 			method: "PATCH",
-			body: { locations: changes.value },
+			body: {
+				id: 111,
+				updatedAt: "",
+				locations: changes.value
+			} satisfies ApiSchedule,
 		});
 		changes.value = [];
 	} catch (err: any) {
@@ -155,8 +166,11 @@ async function saveLocations() {
 }
 
 const locations = computed(() => {
-	const data = [...schedule.value.locations];
-	applyChangeArray(changes.value.filter(change => change.op === "set"), data);
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
+	const data = [...schedule.value.locations ?? []];
+	applyUpdatesToArray(changes.value.filter(change => !change.deleted), data);
 	return data;
 });
 </script>
diff --git a/components/RolesTable.vue b/components/RolesTable.vue
index f6af6a7..60cbe82 100644
--- a/components/RolesTable.vue
+++ b/components/RolesTable.vue
@@ -1,5 +1,8 @@
 <template>
-	<div>
+	<div v-if="schedule.deleted">
+		Error: Unexpected deleted schedule.
+	</div>
+	<div v-else>
 		<table>
 			<thead>
 				<tr>
@@ -12,7 +15,7 @@
 			<tbody>
 				<template v-if="edit">
 					<tr
-						v-for="role in roles"
+						v-for="role in roles.filter(r => !r.deleted)"
 						:key="role.id"
 						:class="{ removed: removed.has(role.id) }"
 					>
@@ -38,14 +41,14 @@
 								@click="delRole(role.id)"
 							>Delete</button>
 							<button
-								v-if="changes.some(c => c.data.id === role.id)"
+								v-if="changes.some(c => c.id === role.id)"
 								type="button"
 								@click="revertRole(role.id)"
 							>Revert</button>
 						</td>
 					</tr>
 					<tr>
-						<td>{{ toId(newRoleName) }}</td>
+						<td>{{ newRoleId }}</td>
 						<td>
 							<input
 								type="text"
@@ -73,7 +76,7 @@
 				</template>
 				<template v-else>
 					<tr
-						v-for="role in roles"
+						v-for="role in roles.filter(r => !r.deleted)"
 						:key="role.id"
 					>
 						<td>{{ role.id }}</td>
@@ -102,8 +105,8 @@
 </template>
 
 <script lang="ts" setup>
-import type { ChangeRecord, Role } from '~/shared/types/schedule';
-import { applyChangeArray } from '~/shared/utils/changes';
+import type { ApiSchedule, ApiScheduleRole } from '~/shared/types/api';
+import { applyUpdatesToArray } from '~/shared/utils/update';
 import { toId } from '~/shared/utils/functions';
 
 defineProps<{
@@ -112,14 +115,14 @@ defineProps<{
 
 const schedule = await useSchedule();
 
-const changes = ref<ChangeRecord<Role>[]>([]);
-const removed = computed(() => new Set(changes.value.filter(c => c.op === "del").map(c => c.data.id)));
+const changes = ref<ApiScheduleRole[]>([]);
+const removed = computed(() => new Set(changes.value.filter(c => c.deleted).map(c => c.id)));
 function replaceChange(
-	change: ChangeRecord<Role>,
-	changes: ChangeRecord<Role>[],
+	change: ApiScheduleRole,
+	changes: ApiScheduleRole[],
 ) {
 	const index = changes.findIndex(item => (
-		item.op === change.op && item.data.id === change.data.id
+		item.deleted === change.deleted && item.id === change.id
 	));
 	const copy = [...changes];
 	if (index !== -1)
@@ -128,14 +131,24 @@ function replaceChange(
 		copy.push(change);
 	return copy;
 }
-function revertChange(id: string, changes: ChangeRecord<Role>[]) {
-	return changes.filter(change => change.data.id !== id);
+function revertChange(id: number, changes: ApiScheduleRole[]) {
+	return changes.filter(change => change.id !== id);
 }
 
 const newRoleName = ref("");
+const newRoleId = computed(() => {
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
+	return Math.max(
+		1,
+		...schedule.value.roles?.map(r => r.id) ?? [],
+		...changes.value.map(c => c.id)
+	) + 1;
+});
 const newRoleDescription = ref("");
 function editRole(
-	role: Role,
+	role: Extract<ApiScheduleRole, { deleted?: false }>,
 	edits: { name?: string, description?: string }
 ) {
 	const copy = { ...role };
@@ -145,21 +158,23 @@ function editRole(
 	if (edits.description !== undefined) {
 		copy.description = edits.description || undefined;
 	}
-	const change = { op: "set" as const, data: copy };
+	changes.value = replaceChange(copy, changes.value);
+}
+function delRole(id: number) {
+	const change = { id, updatedAt: "", deleted: true as const };
 	changes.value = replaceChange(change, changes.value);
 }
-function delRole(id: string) {
-	const change = { op: "del" as const, data: { id } };
-	changes.value = replaceChange(change, changes.value);
-}
-function revertRole(id: string) {
+function revertRole(id: number) {
 	changes.value = revertChange(id, changes.value);
 }
 function roleExists(name: string) {
-	const id = toId(name);
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
+	name = toId(name);
 	return (
-		schedule.value.roles?.some(e => e.id === id)
-		|| changes.value.some(c => c.data.id === id)
+		schedule.value.roles?.some(r => !r.deleted && toId(r.name) === name)
+		|| changes.value.some(c => !c.deleted && c.name === name)
 	);
 }
 function newRole() {
@@ -167,14 +182,15 @@ function newRole() {
 		alert(`Role ${newRoleName.value} already exists`);
 		return;
 	}
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
 	const change = {
-		op: "set" as const,
-		data: {
-			id: toId(newRoleName.value),
-			name: newRoleName.value,
-			description: newRoleDescription.value || undefined,
-			slots: [],
-		},
+		id: newRoleId.value,
+		updatedAt: "",
+		name: newRoleName.value,
+		description: newRoleDescription.value || undefined,
+		slots: [],
 	};
 	changes.value = replaceChange(change, changes.value);
 	newRoleName.value = "";
@@ -184,7 +200,11 @@ async function saveRoles() {
 	try {
 		await $fetch("/api/schedule", {
 			method: "PATCH",
-			body: { roles: changes.value },
+			body: {
+				id: 111,
+				updatedAt: "",
+				roles: changes.value
+			} satisfies ApiSchedule,
 		});
 		changes.value = [];
 	} catch (err: any) {
@@ -194,8 +214,11 @@ async function saveRoles() {
 }
 
 const roles = computed(() => {
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
 	const data = [...schedule.value.roles ?? []];
-	applyChangeArray(changes.value.filter(change => change.op === "set"), data);
+	applyUpdatesToArray(changes.value.filter(change => !change.deleted), data);
 	return data;
 });
 </script>
diff --git a/components/ScheduleTable.vue b/components/ScheduleTable.vue
index 1440256..410c123 100644
--- a/components/ScheduleTable.vue
+++ b/components/ScheduleTable.vue
@@ -1,5 +1,8 @@
 <template>
-	<div>
+	<div v-if="schedule.deleted">
+		Error: Unexpected deleted schedule.
+	</div>
+	<div v-else>
 		<Timetable :schedule="schedulePreview" :eventSlotFilter :shiftSlotFilter />
 		<table>
 			<thead>
@@ -47,7 +50,7 @@
 									v-model="newEventLocation"
 								>
 									<option
-										v-for="location in schedule.locations"
+										v-for="location in schedule.locations?.filter(l => !l.deleted)"
 										:key="location.id"
 										:value="location.id"
 										:selected="location.id === newEventLocation"
@@ -99,14 +102,14 @@
 							<td>{{ status(es) }}</td>
 							<td>
 								<select
-									:value="es.location"
-									@change="editEventSlot(es, { location: ($event as any).target.value })"
+									:value="es.locationId"
+									@change="editEventSlot(es, { locationId: parseInt(($event as any).target.value) })"
 								>
 									<option
-										v-for="location in schedule.locations"
+										v-for="location in schedule.locations?.filter(l => !l.deleted)"
 										:key="location.id"
 										:value="location.id"
-										:selected="location.id === es.location"
+										:selected="location.id === es.locationId"
 									>{{ location.name }}</option>
 								</select>
 							</td>
@@ -124,7 +127,7 @@
 									@click="delEventSlot(es)"
 								>Remove</button>
 								<button
-									v-if="changes.some(c => c.data.id === es.id)"
+									v-if="changes.some(c => c.id === es.id)"
 									type="button"
 									@click="revertEventSlot(es.id)"
 								>Revert</button>
@@ -186,7 +189,7 @@
 							<td>{{ es.end.diff(es.start).toFormat('hh:mm') }}</td>
 							<td>{{ es.name }}</td>
 							<td>{{ status(es) }}</td>
-							<td>{{ es.location }}</td>
+							<td>{{ es.locationId }}</td>
 							<td><AssignedCrew :modelValue="es.assigned" :edit="false" /></td>
 						</template>
 					</tr>
@@ -205,13 +208,13 @@
 			<b>EventSlot changes</b>
 			<ol>
 				<li v-for="change in changes">
-					<pre><code>{{ JSON.stringify((({ event, slot, ...data }) => ({ op: change.op, data }))(change.data as any), undefined, "  ") }}</code></pre>
+					<pre><code>{{ JSON.stringify((({ event, slot, ...data }) => data)(change as any), undefined, "  ") }}</code></pre>
 				</li>
 			</ol>
 			<b>ScheduleEvent changes</b>
 			<ol>
 				<li v-for="change in scheduleChanges">
-					<pre><code>{{ JSON.stringify((({ event, slot, ...data }) => ({ op: change.op, data }))(change.data as any), undefined, "  ") }}</code></pre>
+					<pre><code>{{ JSON.stringify((({ event, slot, ...data }) => data)(change as any), undefined, "  ") }}</code></pre>
 				</li>
 			</ol>
 		</details>
@@ -220,25 +223,28 @@
 
 <script lang="ts" setup>
 import { DateTime, Duration } from 'luxon';
-import type { ChangeRecord, Schedule, ScheduleEvent, ScheduleLocation, ShiftSlot, TimeSlot } from '~/shared/types/schedule';
-import { applyChangeArray } from '~/shared/utils/changes';
-import { enumerate, pairs, toId } from '~/shared/utils/functions';
+import type { ApiSchedule, ApiScheduleEvent, ApiScheduleEventSlot, ApiScheduleShift, ApiScheduleShiftSlot } from '~/shared/types/api';
+import type { Entity } from '~/shared/types/common';
+import { enumerate, pairs } from '~/shared/utils/functions';
+import { applyUpdatesToArray } from '~/shared/utils/update';
 
 const props = defineProps<{
 	edit?: boolean,
-	location?: string,
-	eventSlotFilter?: (slot: TimeSlot) => boolean,
-	shiftSlotFilter?: (slot: ShiftSlot) => boolean,
+	locationId?: number,
+	eventSlotFilter?: (slot: ApiScheduleEventSlot) => boolean,
+	shiftSlotFilter?: (slot: ApiScheduleShiftSlot) => boolean,
 }>();
 
 interface EventSlot {
 	type: "slot",
-	id: string,
-	event?: ScheduleEvent,
-	slot?: TimeSlot,
-	origLocation: string,
+	id: number,
+	updatedAt: string,
+	deleted?: boolean,
+	event?: Extract<ApiScheduleEvent, { deleted?: false }>,
+	slot?: ApiScheduleEventSlot,
+	origLocation: number,
 	name: string,
-	location: string,
+	locationId: number,
 	assigned: number[],
 	start: DateTime,
 	end: DateTime,
@@ -250,57 +256,69 @@ interface Gap {
 	event?: undefined,
 	slot?: undefined,
 	name?: undefined,
-	location?: string,
+	locationId?: number,
 	start: DateTime,
 	end: DateTime,
 }
 
 function status(eventSlot: EventSlot) {
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
 	if (
 		!eventSlot.event
 		|| eventSlot.event.name !== eventSlot.name
 	) {
-		const event = schedule.value.events.find(event => event.name === eventSlot.name);
+		const event = schedule.value.events?.find(event => !event.deleted && event.name === eventSlot.name);
 		return event ? "L" : "N";
 	}
 	return eventSlot.event.slots.length === 1 ? "" : eventSlot.event.slots.length;
 }
 
 // Filter out set records where a del record exists for the same id.
-function filterSetOps<T extends { op: "set" | "del", data: { id: string }}>(changes: T[]) {
-	const deleteIds = new Set(changes.filter(c => c.op === "del").map(c => c.data.id));
-	return changes.filter(c => c.op !== "set" || !deleteIds.has(c.data.id));
+function filterSetOps<T extends Entity>(changes: T[]) {
+	const deleteIds = new Set(changes.filter(c => c.deleted).map(c => c.id));
+	return changes.filter(c => c.deleted || !deleteIds.has(c.id));
 }
 
 function findEvent(
 	eventSlot: EventSlot,
-	changes: ChangeRecord<ScheduleEvent>[],
-	schedule: Schedule,
+	changes: ApiScheduleEvent[],
+	schedule: ApiSchedule,
 ) {
-	let setEvent = changes.find(
-		c => c.op === "set" && c.data.name === eventSlot.name
-	)?.data as ScheduleEvent | undefined;
+	if (schedule.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
+	let setEvent = changes.filter(
+		c => !c.deleted
+	).find(
+		c => c.name === eventSlot.name
+	);
 	if (!setEvent && eventSlot.event && eventSlot.event.name === eventSlot.name) {
 		setEvent = eventSlot.event;
 	}
 	if (!setEvent) {
-		setEvent = schedule.events.find(e => e.name === eventSlot.name);
+		setEvent = schedule.events?.filter(e => !e.deleted).find(e => e.name === eventSlot.name);
 	}
 	let delEvent;
 	if (eventSlot.event) {
-		delEvent = changes.find(
-			c => c.op === "set" && c.data.name === eventSlot.event!.name
-		)?.data as ScheduleEvent | undefined;
+		delEvent = changes.filter(c => !c.deleted).find(
+			c => c.name === eventSlot.event!.name
+		);
 		if (!delEvent) {
-			delEvent = schedule.events.find(e => e.name === eventSlot.event!.name);
+			delEvent = schedule.events?.filter(e => !e.deleted).find(e => e.name === eventSlot.event!.name);
 		}
 	}
 	return { setEvent, delEvent };
 }
 
-function removeSlotLocation(event: ScheduleEvent, oldSlot: TimeSlot, location: string) {
+function removeSlotLocation(
+	event: Extract<ApiScheduleEvent, { deleted?: false }>,
+	oldSlot: ApiScheduleEventSlot,
+	locationId: number
+) {
 	// If location is an exact match remove the whole slot
-	if (oldSlot.locations.length === 1 && oldSlot.locations[0] === location) {
+	if (oldSlot.locationIds.length === 1 && oldSlot.locationIds[0] === locationId) {
 		return {
 			...event,
 			slots: event.slots.filter(s => s.id !== oldSlot.id),
@@ -312,18 +330,21 @@ function removeSlotLocation(event: ScheduleEvent, oldSlot: TimeSlot, location: s
 		slots: event.slots.map(
 			s => s.id !== oldSlot.id ? s : {
 				...s,
-				locations: s.locations.filter(l => l !== location)
+				locationIds: s.locationIds.filter(id => id !== locationId)
 			}
 		),
 	};
 }
 
-function mergeSlot(event: ScheduleEvent, eventSlot: EventSlot): ScheduleEvent {
+function mergeSlot(
+	event: Extract<ApiScheduleEvent, { deleted?: false }>,
+	eventSlot: EventSlot,
+): Extract<ApiScheduleEvent, { deleted?: false }> {
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
 	const oldSlot = event.slots.find(s => s.id === eventSlot.id);
-	const nextId = Math.max(-1, ...event.slots.map(s => {
-		const id = /-(\d+)$/.exec(s.id)?.[1];
-		return id ? parseInt(id) : 0;
-	})) + 1;
+	const nextId = Math.max(0, ...schedule.value.events?.filter(e => !e.deleted).flatMap(e => e.slots.map(slot => slot.id)) ?? []) + 1;
 	const start = eventSlot.start.toUTC().toISO({ suppressSeconds: true })!;
 	const end = eventSlot.end.toUTC().toISO({ suppressSeconds: true })!;
 
@@ -332,7 +353,7 @@ function mergeSlot(event: ScheduleEvent, eventSlot: EventSlot): ScheduleEvent {
 		oldSlot
 		&& oldSlot.id === eventSlot.id
 		&& (
-			oldSlot.locations.length <= 1
+			oldSlot.locationIds.length <= 1
 			|| oldSlot.start === start && oldSlot.end === end
 		)
 	) {
@@ -341,12 +362,12 @@ function mergeSlot(event: ScheduleEvent, eventSlot: EventSlot): ScheduleEvent {
 			slots: event.slots.map(s => {
 				if (s.id !== oldSlot.id)
 					return s;
-				const locations = new Set(s.locations);
-				locations.delete(eventSlot.origLocation)
-				locations.add(eventSlot.location);
+				const locationIds = new Set(s.locationIds);
+				locationIds.delete(eventSlot.origLocation)
+				locationIds.add(eventSlot.locationId);
 				return {
 					...s,
-					locations: [...locations],
+					locationIds: [...locationIds],
 					assigned: eventSlot.assigned.length ? eventSlot.assigned : undefined,
 					start,
 					end,
@@ -363,8 +384,8 @@ function mergeSlot(event: ScheduleEvent, eventSlot: EventSlot): ScheduleEvent {
 	return {
 		...event,
 		slots: [...event.slots, {
-			id: oldSlot ? oldSlot.id : `${event.id}-${nextId}`,
-			locations: [eventSlot.location],
+			id: oldSlot ? oldSlot.id : nextId,
+			locationIds: [eventSlot.locationId],
 			assigned: eventSlot.assigned.length ? eventSlot.assigned : undefined,
 			start,
 			end,
@@ -373,31 +394,29 @@ function mergeSlot(event: ScheduleEvent, eventSlot: EventSlot): ScheduleEvent {
 }
 
 const scheduleChanges = computed(() => {
-	let eventChanges: ChangeRecord<ScheduleEvent>[] = [];
+	let eventChanges: Extract<ApiScheduleEvent, { deleted?: false}>[] = [];
 	for (const change of filterSetOps(changes.value)) {
-		if (change.op === "set") {
-			let { setEvent, delEvent } = findEvent(change.data, eventChanges, schedule.value);
+		if (!change.deleted) {
+			let { setEvent, delEvent } = findEvent(change, eventChanges, schedule.value);
 			if (delEvent && delEvent !== setEvent) {
-				eventChanges = removeSlot(eventChanges, delEvent, change.data);
+				eventChanges = removeSlot(eventChanges, delEvent, change);
 			}
 			if (!setEvent) {
 				setEvent = {
-					id: toId(change.data.name),
-					name: change.data.name,
+					id: Math.floor(Math.random() * -1000), // XXX This wont work.
+					updatedAt: "",
+					name: change.name,
 					crew: true,
 					slots: [],
 				};
 			}
 
-			eventChanges = replaceChange({
-				op: "set",
-				data: mergeSlot(setEvent, change.data),
-			}, eventChanges);
+			eventChanges = replaceChange(mergeSlot(setEvent, change), eventChanges);
 
-		} else if (change.op === "del") {
-			let { delEvent } = findEvent(change.data, eventChanges, schedule.value);
+		} else if (change.deleted) {
+			let { delEvent } = findEvent(change, eventChanges, schedule.value);
 			if (delEvent) {
-				eventChanges = removeSlot(eventChanges, delEvent, change.data);
+				eventChanges = removeSlot(eventChanges, delEvent, change);
 			}
 		}
 	}
@@ -405,21 +424,28 @@ const scheduleChanges = computed(() => {
 });
 
 const schedulePreview = computed(() => {
-	const events = [...schedule.value.events]
-	applyChangeArray(scheduleChanges.value, events);
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
+	const events = [...schedule.value.events ?? []]
+	applyUpdatesToArray(scheduleChanges.value, events);
 	return {
 		...schedule.value,
 		events,
 	};
 });
 
-function removeSlot(eventChanges: ChangeRecord<ScheduleEvent>[], event: ScheduleEvent, eventSlot: EventSlot) {
+function removeSlot(
+	eventChanges: Extract<ApiScheduleEvent, { deleted?: false }>[],
+	event: Extract<ApiScheduleEvent, { deleted?: false }>,
+	eventSlot: EventSlot,
+) {
 	let oldSlot = event.slots.find(s => s.id === eventSlot.id);
 	if (oldSlot) {
-		eventChanges = replaceChange({
-			op: "set",
-			data: removeSlotLocation(event, oldSlot, eventSlot.origLocation),
-		}, eventChanges);
+		eventChanges = replaceChange(
+			removeSlotLocation(event, oldSlot, eventSlot.origLocation),
+			eventChanges,
+		);
 	}
 	return eventChanges;
 }
@@ -427,17 +453,15 @@ function removeSlot(eventChanges: ChangeRecord<ScheduleEvent>[], event: Schedule
 const accountStore = useAccountStore();
 const schedule = await useSchedule();
 
-type EventSlotChange = { op: "set" | "del", data: EventSlot } ;
+const changes = ref<EventSlot[]>([]);
+const removed = computed(() => new Set(changes.value.filter(c => c.deleted).map(c => c.id)));
 
-const changes = ref<EventSlotChange[]>([]);
-const removed = computed(() => new Set(changes.value.filter(c => c.op === "del").map(c => c.data.id)));
-
-function replaceChange<T extends { op: "set" | "del", data: { id: string  }}>(
+function replaceChange<T extends Entity>(
 	change: T,
 	changes: T[],
 ) {
 	const index = changes.findIndex(item => (
-		item.op === change.op && item.data.id === change.data.id
+		item.deleted === change.deleted && item.id === change.id
 	));
 	const copy = [...changes];
 	if (index !== -1)
@@ -446,8 +470,8 @@ function replaceChange<T extends { op: "set" | "del", data: { id: string  }}>(
 		copy.push(change);
 	return copy;
 }
-function revertChange<T extends { op: "set" | "del", data: { id: string }}>(id: string, changes: T[]) {
-	return changes.filter(change => change.data.id !== id);
+function revertChange<T extends Entity>(id: number, changes: T[]) {
+	return changes.filter(change => change.id !== id);
 }
 
 const oneDayMs = 24 * 60 * 60 * 1000;
@@ -472,9 +496,9 @@ const newEventEnd = computed({
 		newEventDuration.value = dropDay(end.diff(start)).toFormat("hh:mm");
 	},
 });
-const newEventLocation = ref(props.location);
-watch(() => props.location, () => {
-	newEventLocation.value = props.location;
+const newEventLocation = ref(props.locationId);
+watch(() => props.locationId, () => {
+	newEventLocation.value = props.locationId;
 });
 
 function endFromTime(start: DateTime, time: string) {
@@ -499,7 +523,7 @@ function editEventSlot(
 		end?: string,
 		duration?: string,
 		name?: string,
-		location?: string,
+		locationId?: number,
 		assigned?: number[],
 	}
 ) {
@@ -512,7 +536,6 @@ function editEventSlot(
 		};
 	}
 	if (edits.end !== undefined) {
-
 		eventSlot = {
 			...eventSlot,
 			end: endFromTime(eventSlot.start, edits.end),
@@ -530,10 +553,10 @@ function editEventSlot(
 			name: edits.name,
 		};
 	}
-	if (edits.location !== undefined) {
+	if (edits.locationId !== undefined) {
 		eventSlot = {
 			...eventSlot,
-			location: edits.location,
+			locationId: edits.locationId,
 		};
 	}
 	if (edits.assigned !== undefined) {
@@ -542,20 +565,22 @@ function editEventSlot(
 			assigned: edits.assigned,
 		};
 	}
-	const change = { op: "set" as const, data: eventSlot };
-	changes.value = replaceChange(change, changes.value);
+	changes.value = replaceChange(eventSlot, changes.value);
 }
 function delEventSlot(eventSlot: EventSlot) {
-	const change = { op: "del" as const, data: eventSlot };
+	const change = {
+		...eventSlot,
+		deleted: true,
+	};
 	changes.value = replaceChange(change, changes.value);
 }
-function revertEventSlot(id: string) {
+function revertEventSlot(id: number) {
 	changes.value = revertChange(id, changes.value);
 }
 function newEventSlot(options: { start?: DateTime, end?: DateTime } = {}) {
 	const name = newEventName.value;
-	const location = newEventLocation.value;
-	if (!location) {
+	const locationId = newEventLocation.value;
+	if (!locationId) {
 		alert("Invalid location");
 		return;
 	}
@@ -580,27 +605,30 @@ function newEventSlot(options: { start?: DateTime, end?: DateTime } = {}) {
 		alert("Invalid start and/or end time");
 		return;
 	}
-	const change: ChangeRecord<EventSlot> = {
-		op: "set" as const,
-		data: {
-			type: "slot",
-			id: `$new-${Date.now()}`,
-			name,
-			origLocation: location,
-			location,
-			assigned: [],
-			start,
-			end,
-		},
+	const change: EventSlot = {
+		type: "slot",
+		updatedAt: "",
+		id: Math.floor(Math.random() * -1000), // XXX this wont work.
+		name,
+		origLocation: locationId,
+		locationId,
+		assigned: [],
+		start,
+		end,
 	};
 	newEventName.value = "";
 	changes.value = replaceChange(change, changes.value);
 }
+
 async function saveEventSlots() {
 	try {
 		await $fetch("/api/schedule", {
 			method: "PATCH",
-			body: { events: scheduleChanges.value },
+			body: {
+				id: 111,
+				updatedAt: "",
+				events: scheduleChanges.value,
+			} satisfies ApiSchedule,
 		});
 		changes.value = [];
 	} catch (err: any) {
@@ -620,30 +648,36 @@ function gapFormat(gap: Gap) {
 }
 
 const eventSlots = computed(() => {
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
 	const data: (EventSlot | Gap)[] = [];
-	for (const event of schedule.value.events) {
+	for (const event of schedule.value.events ?? []) {
+		if (event.deleted)
+			continue;
 		for (const slot of event.slots) {
 			if (props.eventSlotFilter && !props.eventSlotFilter(slot))
 				continue;
-			for (const location of slot.locations) {
-				if (props.location !== undefined && location !== props.location)
+			for (const locationId of slot.locationIds) {
+				if (props.locationId !== undefined && locationId !== props.locationId)
 					continue;
 				data.push({
 					type: "slot",
 					id: slot.id,
+					updatedAt: "",
 					event,
 					slot,
 					name: event.name,
-					location,
+					locationId,
 					assigned: slot.assigned ?? [],
-					origLocation: location,
+					origLocation: locationId,
 					start: DateTime.fromISO(slot.start, { zone: accountStore.activeTimezone, locale: "en-US" }),
 					end: DateTime.fromISO(slot.end, { zone: accountStore.activeTimezone, locale: "en-US" }),
 				});
 			}
 		}
 	}
-	applyChangeArray(changes.value.filter(change => change.op === "set"), data as EventSlot[]);
+	applyUpdatesToArray(changes.value.filter(c => !c.deleted), data as EventSlot[]);
 	data.sort((a, b) => a.start.toMillis() - b.start.toMillis() || a.end.toMillis() - b.end.toMillis());
 
 	// Insert gaps
@@ -654,7 +688,7 @@ const eventSlots = computed(() => {
 		if (maxEnd < second.start.toMillis()) {
 			gaps.push([index, {
 				type: "gap",
-				location: props.location,
+				locationId: props.locationId,
 				start: DateTime.fromMillis(maxEnd, { locale: "en-US" }),
 				end: second.start,
 			}]);
diff --git a/components/ShiftScheduleTable.vue b/components/ShiftScheduleTable.vue
index 1c4b8a0..45f224a 100644
--- a/components/ShiftScheduleTable.vue
+++ b/components/ShiftScheduleTable.vue
@@ -1,5 +1,8 @@
 <template>
-	<div>
+	<div v-if="schedule.deleted">
+		Error: Unexpected deleted schedule.
+	</div>
+	<div v-else>
 		<Timetable :schedule="schedulePreview" :eventSlotFilter :shiftSlotFilter />
 		<table>
 			<thead>
@@ -47,7 +50,7 @@
 									v-model="newShiftRole"
 								>
 									<option
-										v-for="role in schedule.roles"
+										v-for="role in schedule.roles?.filter(r => !r.deleted)"
 										:key="role.id"
 										:value="role.id"
 										:selected="role.id === newShiftRole"
@@ -99,14 +102,14 @@
 							<td>{{ status(ss) }}</td>
 							<td>
 								<select
-									:value="ss.role"
-									@change="editShiftSlot(ss, { role: ($event as any).target.value })"
+									:value="ss.roleId"
+									@change="editShiftSlot(ss, { roleId: parseInt(($event as any).target.value) })"
 								>
 									<option
-										v-for="role in schedule.roles"
+										v-for="role in schedule.roles?.filter(r => !r.deleted)"
 										:key="role.id"
 										:value="role.id"
-										:selected="role.id === ss.role"
+										:selected="role.id === ss.roleId"
 									>{{ role.name }}</option>
 								</select>
 							</td>
@@ -124,7 +127,7 @@
 									@click="delShiftSlot(ss)"
 								>Remove</button>
 								<button
-									v-if="changes.some(c => c.data.id === ss.id)"
+									v-if="changes.some(c => c.id === ss.id)"
 									type="button"
 									@click="revertShiftSlot(ss.id)"
 								>Revert</button>
@@ -184,7 +187,7 @@
 							<td>{{ ss.end.diff(ss.start).toFormat('hh:mm') }}</td>
 							<td>{{ ss.name }}</td>
 							<td>{{ status(ss) }}</td>
-							<td>{{ ss.role }}</td>
+							<td>{{ ss.roleId }}</td>
 							<td><AssignedCrew :modelValue="ss.assigned" :edit="false" /></td>
 						</template>
 					</tr>
@@ -203,13 +206,13 @@
 			<b>ShiftSlot changes</b>
 			<ol>
 				<li v-for="change in changes">
-					<pre><code>{{ JSON.stringify((({ shift, slot, ...data }) => ({ op: change.op, data }))(change.data as any), undefined, "  ") }}</code></pre>
+					<pre><code>{{ JSON.stringify((({ shift, slot, ...data }) => data)(change as any), undefined, "  ") }}</code></pre>
 				</li>
 			</ol>
 			<b>Shift changes</b>
 			<ol>
 				<li v-for="change in shiftChanges">
-					<pre><code>{{ JSON.stringify((({ shift, slot, ...data }) => ({ op: change.op, data }))(change.data as any), undefined, "  ") }}</code></pre>
+					<pre><code>{{ JSON.stringify((({ shift, slot, ...data }) => data)(change as any), undefined, "  ") }}</code></pre>
 				</li>
 			</ol>
 		</details>
@@ -218,25 +221,28 @@
 
 <script lang="ts" setup>
 import { DateTime, Duration } from 'luxon';
-import type { ChangeRecord, Schedule, Shift, Role, ShiftSlot as ShiftTimeSlot, TimeSlot} from '~/shared/types/schedule';
-import { applyChangeArray } from '~/shared/utils/changes';
-import { enumerate, pairs, toId } from '~/shared/utils/functions';
+import type { ApiSchedule, ApiScheduleEventSlot, ApiScheduleShift, ApiScheduleShiftSlot } from '~/shared/types/api';
+import { applyUpdatesToArray } from '~/shared/utils/update';
+import { enumerate, pairs } from '~/shared/utils/functions';
+import type { Entity } from '~/shared/types/common';
 
 const props = defineProps<{
 	edit?: boolean,
-	role?: string,
-	eventSlotFilter?: (slot: TimeSlot) => boolean,
-	shiftSlotFilter?: (slot: ShiftTimeSlot) => boolean,
+	roleId?: number,
+	eventSlotFilter?: (slot: ApiScheduleEventSlot) => boolean,
+	shiftSlotFilter?: (slot: ApiScheduleShiftSlot) => boolean,
 }>();
 
 interface ShiftSlot {
 	type: "slot",
-	id: string,
-	shift?: Shift,
-	slot?: ShiftTimeSlot,
-	origRole: string,
+	id: number,
+	updatedAt: string,
+	deleted?: boolean,
+	shift?: Extract<ApiScheduleShift, { deleted?: false }>,
+	slot?: ApiScheduleShiftSlot,
+	origRole: number,
 	name: string,
-	role: string,
+	roleId: number,
 	assigned: number[],
 	start: DateTime,
 	end: DateTime,
@@ -248,40 +254,47 @@ interface Gap {
 	shift?: undefined,
 	slot?: undefined,
 	name?: undefined,
-	role?: string,
+	roleId?: number,
 	start: DateTime,
 	end: DateTime,
 }
 
 function status(shiftSlot: ShiftSlot) {
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
 	if (
 		!shiftSlot.shift
 		|| shiftSlot.shift.name !== shiftSlot.name
 	) {
-		const shift = schedule.value.rota?.find(shift => shift.name === shiftSlot.name);
+		const shift = schedule.value.shifts?.find(shift => !shift.deleted && shift.name === shiftSlot.name);
 		return shift ? "L" : "N";
 	}
 	return shiftSlot.shift.slots.length === 1 ? "" : shiftSlot.shift.slots.length;
 }
 
 // Filter out set records where a del record exists for the same id.
-function filterSetOps<T extends { op: "set" | "del", data: { id: string }}>(changes: T[]) {
-	const deleteIds = new Set(changes.filter(c => c.op === "del").map(c => c.data.id));
-	return changes.filter(c => c.op !== "set" || !deleteIds.has(c.data.id));
+function filterSetOps<T extends Entity>(changes: T[]) {
+	const deleteIds = new Set(changes.filter(c => c.deleted).map(c => c.id));
+	return changes.filter(c => c.deleted || !deleteIds.has(c.id));
 }
 
 function findShift(
 	shiftSlot: ShiftSlot,
-	changes: ChangeRecord<Shift>[],
-	schedule: Schedule,
+	changes: ApiScheduleShift[],
+	schedule: ApiSchedule,
 ) {
-	let setShift = changes.find(
+	if (schedule.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
+	let setShift = changes.filter(
+		c => !c.deleted,
+	).find(
 		c => (
-			c.op === "set"
-			&& c.data.name === shiftSlot.name
-			&& c.data.role === shiftSlot.role
+			c.name === shiftSlot.name
+			&& c.roleId === shiftSlot.roleId
 		)
-	)?.data as Shift | undefined;
+	);
 	if (
 		!setShift
 		&& shiftSlot.shift
@@ -290,32 +303,35 @@ function findShift(
 		setShift = shiftSlot.shift;
 	}
 	if (!setShift) {
-		setShift = schedule.rota?.find(e => e.name === shiftSlot.name);
+		setShift = schedule.shifts?.filter(s => !s.deleted).find(s => s.name === shiftSlot.name);
 	}
 	let delShift;
 	if (shiftSlot.shift) {
-		delShift = changes.find(
-			c => c.op === "set" && c.data.name === shiftSlot.shift!.name
-		)?.data as Shift | undefined;
+		delShift = changes.filter(c => !c.deleted).find(
+			c => c.name === shiftSlot.shift!.name
+		);
 		if (!delShift) {
-			delShift = schedule.rota?.find(e => e.name === shiftSlot.shift!.name);
+			delShift = schedule.shifts?.filter(s => !s.deleted).find(s => s.name === shiftSlot.shift!.name);
 		}
 	}
 	return { setShift, delShift };
 }
 
-function mergeSlot(shift: Shift, shiftSlot: ShiftSlot): Shift {
+function mergeSlot(
+	shift: Extract<ApiScheduleShift, { deleted?: false }>,
+	shiftSlot: ShiftSlot,
+): Extract<ApiScheduleShift, { deleted?: false }> {
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
 	const oldSlot = shift.slots.find(s => s.id === shiftSlot.id);
-	const nextId = Math.max(-1, ...shift.slots.map(s => {
-		const id = /-(\d+)$/.exec(s.id)?.[1];
-		return id ? parseInt(id) : 0;
-	})) + 1;
+	const nextId = Math.max(0, ...schedule.value.shifts?.filter(s => !s.deleted).flatMap(s => s.slots.map(slot => slot.id)) ?? []) + 1;
 	const start = shiftSlot.start.toUTC().toISO({ suppressSeconds: true })!;
 	const end = shiftSlot.end.toUTC().toISO({ suppressSeconds: true })!;
 	const assigned = shiftSlot.assigned.length ? shiftSlot.assigned : undefined;
 
-	if (shift.role !== shiftSlot.role) {
-		console.warn(`Attempt to add slot id=${shiftSlot.id} role=${shiftSlot.role} to shift id=${shift.id} role=${shift.role}`);
+	if (shift.roleId !== shiftSlot.roleId) {
+		console.warn(`Attempt to add slot id=${shiftSlot.id} roleId=${shiftSlot.roleId} to shift id=${shift.id} roleId=${shift.roleId}`);
 	}
 
 	// Edit slot in-place if possible
@@ -330,7 +346,7 @@ function mergeSlot(shift: Shift, shiftSlot: ShiftSlot): Shift {
 	return {
 		...shift,
 		slots: [...(oldSlot ? shift.slots.filter(s => s.id !== oldSlot.id) : shift.slots), {
-			id: oldSlot ? oldSlot.id : `${shift.id}-${nextId}`,
+			id: oldSlot ? oldSlot.id : nextId,
 			assigned,
 			start,
 			end,
@@ -339,35 +355,33 @@ function mergeSlot(shift: Shift, shiftSlot: ShiftSlot): Shift {
 }
 
 const shiftChanges = computed(() => {
-	let eventChanges: ChangeRecord<Shift>[] = [];
+	let eventChanges: Extract<ApiScheduleShift, { deleted?: false }>[] = [];
 	for (const change of filterSetOps(changes.value)) {
-		if (change.op === "set") {
-			let { setShift, delShift } = findShift(change.data, eventChanges, schedule.value);
+		if (!change.deleted) {
+			let { setShift, delShift } = findShift(change, eventChanges, schedule.value);
 			if (delShift && delShift !== setShift) {
-				eventChanges = removeSlot(eventChanges, delShift, change.data);
+				eventChanges = removeSlot(eventChanges, delShift, change);
 			}
 			if (!setShift) {
 				setShift = {
-					id: toId(change.data.name),
-					name: change.data.name,
-					role: change.data.role,
+					id: Math.floor(Math.random() * -1000), // XXX This wont work.
+					updatedAt: "",
+					name: change.name,
+					roleId: change.roleId,
 					slots: [],
 				};
 			}
 			setShift = {
 				...setShift,
-				role: change.data.role,
+				roleId: change.roleId,
 			}
 
-			eventChanges = replaceChange({
-				op: "set",
-				data: mergeSlot(setShift, change.data),
-			}, eventChanges);
+			eventChanges = replaceChange(mergeSlot(setShift, change), eventChanges);
 
-		} else if (change.op === "del") {
-			let { delShift } = findShift(change.data, eventChanges, schedule.value);
+		} else if (change.deleted) {
+			let { delShift } = findShift(change, eventChanges, schedule.value);
 			if (delShift) {
-				eventChanges = removeSlot(eventChanges, delShift, change.data);
+				eventChanges = removeSlot(eventChanges, delShift, change);
 			}
 		}
 	}
@@ -375,20 +389,27 @@ const shiftChanges = computed(() => {
 });
 
 const schedulePreview = computed(() => {
-	const rota = [...schedule.value.rota ?? []]
-	applyChangeArray(shiftChanges.value, rota);
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
+	const shifts = [...schedule.value.shifts ?? []]
+	applyUpdatesToArray(shiftChanges.value, shifts);
 	return {
 		...schedule.value,
-		rota,
+		shifts,
 	};
 });
 
-function removeSlot(eventChanges: ChangeRecord<Shift>[], shift: Shift, shiftSlot: ShiftSlot) {
+function removeSlot(
+	eventChanges: Extract<ApiScheduleShift, { deleted?: false }>[],
+	shift: Extract<ApiScheduleShift, { deleted?: false }>,
+	shiftSlot: ShiftSlot,
+) {
 	let oldSlot = shift.slots.find(s => s.id === shiftSlot.id);
 	if (oldSlot) {
 		eventChanges = replaceChange({
-			op: "set",
-			data: { ...shift, slots: shift.slots.filter(s => s.id !== oldSlot.id) },
+			...shift,
+			slots: shift.slots.filter(s => s.id !== oldSlot.id)
 		}, eventChanges);
 	}
 	return eventChanges;
@@ -397,17 +418,15 @@ function removeSlot(eventChanges: ChangeRecord<Shift>[], shift: Shift, shiftSlot
 const accountStore = useAccountStore();
 const schedule = await useSchedule();
 
-type ShiftSlotChange = { op: "set" | "del", data: ShiftSlot } ;
+const changes = ref<ShiftSlot[]>([]);
+const removed = computed(() => new Set(changes.value.filter(c => c.deleted).map(c => c.id)));
 
-const changes = ref<ShiftSlotChange[]>([]);
-const removed = computed(() => new Set(changes.value.filter(c => c.op === "del").map(c => c.data.id)));
-
-function replaceChange<T extends { op: "set" | "del", data: { id: string  }}>(
+function replaceChange<T extends Entity>(
 	change: T,
 	changes: T[],
 ) {
 	const index = changes.findIndex(item => (
-		item.op === change.op && item.data.id === change.data.id
+		item.deleted === change.deleted && item.id === change.id
 	));
 	const copy = [...changes];
 	if (index !== -1)
@@ -416,8 +435,8 @@ function replaceChange<T extends { op: "set" | "del", data: { id: string  }}>(
 		copy.push(change);
 	return copy;
 }
-function revertChange<T extends { op: "set" | "del", data: { id: string }}>(id: string, changes: T[]) {
-	return changes.filter(change => change.data.id !== id);
+function revertChange<T extends Entity>(id: number, changes: T[]) {
+	return changes.filter(change => change.id !== id);
 }
 
 const oneDayMs = 24 * 60 * 60 * 1000;
@@ -442,9 +461,9 @@ const newShiftEnd = computed({
 		newShiftDuration.value = dropDay(end.diff(start)).toFormat("hh:mm");
 	},
 });
-const newShiftRole = ref(props.role);
-watch(() => props.role, () => {
-	newShiftRole.value = props.role;
+const newShiftRole = ref(props.roleId);
+watch(() => props.roleId, () => {
+	newShiftRole.value = props.roleId;
 });
 
 function endFromTime(start: DateTime, time: string) {
@@ -469,7 +488,7 @@ function editShiftSlot(
 		end?: string,
 		duration?: string,
 		name?: string,
-		role?: string,
+		roleId?: number,
 		assigned?: number[],
 	}
 ) {
@@ -482,7 +501,6 @@ function editShiftSlot(
 		};
 	}
 	if (edits.end !== undefined) {
-
 		shiftSlot = {
 			...shiftSlot,
 			end: endFromTime(shiftSlot.start, edits.end),
@@ -500,19 +518,19 @@ function editShiftSlot(
 			name: edits.name,
 		};
 	}
-	if (edits.role !== undefined) {
+	if (edits.roleId !== undefined) {
 		let changesCopy = changes.value;
 		for (const slot of shiftSlots.value) {
 			if (slot.type === "slot" && slot.shift?.name === shiftSlot.name) {
 				changesCopy = replaceChange({
-					op: "set",
-					data: { ...slot, role: edits.role }
+					...slot,
+					roleId: edits.roleId,
 				}, changesCopy);
 			}
 		}
 		changesCopy = replaceChange({
-			op: "set",
-			data: { ...shiftSlot, role: edits.role }
+			...shiftSlot,
+			roleId: edits.roleId,
 		}, changesCopy);
 		changes.value = changesCopy;
 		return;
@@ -523,20 +541,22 @@ function editShiftSlot(
 			assigned: edits.assigned,
 		};
 	}
-	const change = { op: "set" as const, data: shiftSlot };
-	changes.value = replaceChange(change, changes.value);
+	changes.value = replaceChange(shiftSlot, changes.value);
 }
 function delShiftSlot(shiftSlot: ShiftSlot) {
-	const change = { op: "del" as const, data: shiftSlot };
+	const change = {
+		...shiftSlot,
+		deleted: true,
+	};
 	changes.value = replaceChange(change, changes.value);
 }
-function revertShiftSlot(id: string) {
+function revertShiftSlot(id: number) {
 	changes.value = revertChange(id, changes.value);
 }
 function newShiftSlot(options: { start?: DateTime, end?: DateTime } = {}) {
 	const name = newShiftName.value;
-	const role = newShiftRole.value;
-	if (!role) {
+	const roleId = newShiftRole.value;
+	if (!roleId) {
 		alert("Invalid role");
 		return;
 	}
@@ -561,18 +581,16 @@ function newShiftSlot(options: { start?: DateTime, end?: DateTime } = {}) {
 		alert("Invalid start and/or end time");
 		return;
 	}
-	const change: ChangeRecord<ShiftSlot> = {
-		op: "set" as const,
-		data: {
-			type: "slot",
-			id: `$new-${Date.now()}`,
-			name,
-			origRole: role,
-			role,
-			assigned: [],
-			start,
-			end,
-		},
+	const change: ShiftSlot = {
+		type: "slot",
+		updatedAt: "",
+		id: Math.floor(Math.random() * -1000), // XXX this wont work.
+		name,
+		origRole: roleId,
+		roleId,
+		assigned: [],
+		start,
+		end,
 	};
 	newShiftName.value = "";
 	changes.value = replaceChange(change, changes.value);
@@ -581,7 +599,11 @@ async function saveShiftSlots() {
 	try {
 		await $fetch("/api/schedule", {
 			method: "PATCH",
-			body: { rota: shiftChanges.value },
+			body: {
+				id: 111,
+				updatedAt: "",
+				shifts: shiftChanges.value
+			} satisfies ApiSchedule,
 		});
 		changes.value = [];
 	} catch (err: any) {
@@ -601,9 +623,12 @@ function gapFormat(gap: Gap) {
 }
 
 const shiftSlots = computed(() => {
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
 	const data: (ShiftSlot | Gap)[] = [];
-	for (const shift of schedule.value.rota ?? []) {
-		if (props.role !== undefined && shift.role !== props.role)
+	for (const shift of schedule.value.shifts ?? []) {
+		if (shift.deleted || props.roleId !== undefined && shift.roleId !== props.roleId)
 			continue;
 		for (const slot of shift.slots) {
 			if (props.shiftSlotFilter && !props.shiftSlotFilter(slot))
@@ -611,18 +636,19 @@ const shiftSlots = computed(() => {
 			data.push({
 				type: "slot",
 				id: slot.id,
+				updatedAt: "",
 				shift,
 				slot,
 				name: shift.name,
-				role: shift.role,
+				roleId: shift.roleId,
 				assigned: slot.assigned ?? [],
-				origRole: shift.role,
+				origRole: shift.roleId,
 				start: DateTime.fromISO(slot.start, { zone: accountStore.activeTimezone, locale: "en-US" }),
 				end: DateTime.fromISO(slot.end, { zone: accountStore.activeTimezone, locale: "en-US" }),
 			});
 		}
 	}
-	applyChangeArray(changes.value.filter(change => change.op === "set"), data as ShiftSlot[]);
+	applyUpdatesToArray(changes.value.filter(c => !c.deleted), data as ShiftSlot[]);
 	data.sort((a, b) => a.start.toMillis() - b.start.toMillis() || a.end.toMillis() - b.end.toMillis());
 
 	// Insert gaps
@@ -633,7 +659,7 @@ const shiftSlots = computed(() => {
 		if (maxEnd < second.start.toMillis()) {
 			gaps.push([index, {
 				type: "gap",
-				role: props.role,
+				roleId: props.roleId,
 				start: DateTime.fromMillis(maxEnd, { locale: "en-US" }),
 				end: second.start,
 			}]);
diff --git a/components/ShiftsTable.vue b/components/ShiftsTable.vue
index eaa202a..3cd468a 100644
--- a/components/ShiftsTable.vue
+++ b/components/ShiftsTable.vue
@@ -1,5 +1,8 @@
 <template>
-	<div>
+	<div v-if="schedule.deleted">
+		Error: Unexpected deleted schedule.
+	</div>
+	<div v-else>
 		<table>
 			<thead>
 				<tr>
@@ -14,7 +17,7 @@
 			<tbody>
 				<template v-if="edit">
 					<tr
-						v-for="shift in shifts"
+						v-for="shift in shifts?.filter(s => !s.deleted)"
 						:key="shift.id"
 						:class="{ removed: removed.has(shift.id) }"
 					>
@@ -28,14 +31,14 @@
 						</td>
 						<td>
 							<select
-								:value="shift.role"
-								@change="editShift(shift, { role: ($event as any).target.value })"
+								:value="shift.roleId"
+								@change="editShift(shift, { roleId: ($event as any).target.value })"
 							>
 								<option
-									v-for="role in schedule.roles"
+									v-for="role in schedule.roles?.filter(r => !r.deleted)"
 									:key="role.id"
 									:value="role.id"
-									:selected="shift.role === role.id"
+									:selected="shift.roleId === role.id"
 								>{{ role.name }}</option>
 							</select>
 						</td>
@@ -54,14 +57,14 @@
 								@click="delShift(shift.id)"
 							>Delete</button>
 							<button
-								v-if="changes.some(c => c.data.id === shift.id)"
+								v-if="changes.some(c => c.id === shift.id)"
 								type="button"
 								@click="revertShift(shift.id)"
 							>Revert</button>
 						</td>
 					</tr>
 					<tr>
-						<td>{{ toId(newShiftName) }}</td>
+						<td>{{ newShiftId }}</td>
 						<td>
 							<input
 								type="text"
@@ -71,7 +74,7 @@
 						<td>
 							<select v-model="newShiftRole">
 								<option
-									v-for="role in schedule.roles"
+									v-for="role in schedule.roles?.filter(r => !r.deleted)"
 									:key="role.id"
 									:value="role.id"
 									:selected="role.id === newShiftRole"
@@ -100,12 +103,12 @@
 				</template>
 				<template v-else>
 					<tr
-						v-for="shift in shifts"
+						v-for="shift in shifts?.filter(s => !s.deleted)"
 						:key="shift.id"
 					>
 						<td>{{ shift.id }}</td>
 						<td>{{ shift.name }}</td>
-						<td>{{ shift.role }}</td>
+						<td>{{ shift.roleId }}</td>
 						<td>{{ shift.slots.length ? shift.slots.length : "" }}</td>
 						<td>{{ shift.description }}</td>
 					</tr>
@@ -131,25 +134,25 @@
 </template>
 
 <script lang="ts" setup>
-import type { ChangeRecord, Shift } from '~/shared/types/schedule';
-import { applyChangeArray } from '~/shared/utils/changes';
+import type { ApiSchedule, ApiScheduleShift } from '~/shared/types/api';
 import { toId } from '~/shared/utils/functions';
+import { applyUpdatesToArray } from '~/shared/utils/update';
 
 const props = defineProps<{
 	edit?: boolean,
-	role?: string,
+	roleId?: number,
 }>();
 
 const schedule = await useSchedule();
 
-const changes = ref<ChangeRecord<Shift>[]>([]);
-const removed = computed(() => new Set(changes.value.filter(c => c.op === "del").map(c => c.data.id)));
+const changes = ref<ApiScheduleShift[]>([]);
+const removed = computed(() => new Set(changes.value.filter(c => c.deleted).map(c => c.id)));
 function replaceChange(
-	change: ChangeRecord<Shift>,
-	changes: ChangeRecord<Shift>[],
+	change: ApiScheduleShift,
+	changes: ApiScheduleShift[],
 ) {
 	const index = changes.findIndex(item => (
-		item.op === change.op && item.data.id === change.data.id
+		item.deleted === change.deleted && item.id === change.id
 	));
 	const copy = [...changes];
 	if (index !== -1)
@@ -158,19 +161,29 @@ function replaceChange(
 		copy.push(change);
 	return copy;
 }
-function revertChange(id: string, changes: ChangeRecord<Shift>[]) {
-	return changes.filter(change => change.data.id !== id);
+function revertChange(id: number, changes: ApiScheduleShift[]) {
+	return changes.filter(change => change.id !== id);
 }
 
 const newShiftName = ref("");
-const newShiftRole = ref(props.role);
-watch(() => props.role, () => {
-	newShiftRole.value = props.role;
+const newShiftId = computed(() => {
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
+	return Math.max(
+		1,
+		...schedule.value.shifts?.map(r => r.id) ?? [],
+		...changes.value.map(c => c.id)
+	) + 1;
+});
+const newShiftRole = ref(props.roleId);
+watch(() => props.roleId, () => {
+	newShiftRole.value = props.roleId;
 });
 const newShiftDescription = ref("");
 function editShift(
-	shift: Shift,
-	edits: { name?: string, description?: string, role?: string }
+	shift: Extract<ApiScheduleShift, { deleted?: false }>,
+	edits: { name?: string, description?: string, roleId?: number }
 ) {
 	const copy = { ...shift };
 	if (edits.name !== undefined) {
@@ -179,24 +192,26 @@ function editShift(
 	if (edits.description !== undefined) {
 		copy.description = edits.description || undefined;
 	}
-	if (edits.role !== undefined) {
-		copy.role = edits.role;
+	if (edits.roleId !== undefined) {
+		copy.roleId = edits.roleId;
 	}
-	const change = { op: "set" as const, data: copy };
+	changes.value = replaceChange(copy, changes.value);
+}
+function delShift(id: number) {
+	const change = { id, updatedAt: "", deleted: true as const };
 	changes.value = replaceChange(change, changes.value);
 }
-function delShift(id: string) {
-	const change = { op: "del" as const, data: { id } };
-	changes.value = replaceChange(change, changes.value);
-}
-function revertShift(id: string) {
+function revertShift(id: number) {
 	changes.value = revertChange(id, changes.value);
 }
 function shiftExists(name: string) {
-	const id = toId(name);
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
+	name = toId(name);
 	return (
-		schedule.value.rota?.some(e => e.id === id)
-		|| changes.value.some(c => c.data.id === id)
+		schedule.value.shifts?.some(s => !s.deleted && toId(s.name) === name)
+		|| changes.value.some(c => !c.deleted && c.name === name)
 	);
 }
 function newShift() {
@@ -204,19 +219,20 @@ function newShift() {
 		alert(`Shift ${newShiftName.value} already exists`);
 		return;
 	}
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
 	if (!newShiftRole.value) {
 		alert(`Invalid role`);
 		return;
 	}
 	const change = {
-		op: "set" as const,
-		data: {
-			id: toId(newShiftName.value),
-			name: newShiftName.value,
-			role: newShiftRole.value,
-			description: newShiftDescription.value || undefined,
-			slots: [],
-		},
+		id: newShiftId.value,
+		updatedAt: "",
+		name: newShiftName.value,
+		roleId: newShiftRole.value,
+		description: newShiftDescription.value || undefined,
+		slots: [],
 	};
 	changes.value = replaceChange(change, changes.value);
 	newShiftName.value = "";
@@ -226,7 +242,11 @@ async function saveShifts() {
 	try {
 		await $fetch("/api/schedule", {
 			method: "PATCH",
-			body: { rota: changes.value },
+			body: {
+				id: 111,
+				updatedAt: "",
+				shifts: changes.value
+			} satisfies ApiSchedule,
 		});
 		changes.value = [];
 	} catch (err: any) {
@@ -236,8 +256,11 @@ async function saveShifts() {
 }
 
 const shifts = computed(() => {
-	const data = [...schedule.value.rota ?? []].filter(shift => !props.role || shift.role === props.role);
-	applyChangeArray(changes.value.filter(change => change.op === "set"), data);
+	if (schedule.value.deleted) {
+		throw new Error("Unexpected deleted schedule");
+	}
+	const data = [...schedule.value.shifts ?? []].filter(shift => !shift.deleted && (!props.roleId || shift.roleId === props.roleId));
+	applyUpdatesToArray(changes.value.filter(change => !change.deleted), data);
 	return data;
 });
 </script>
diff --git a/components/Timetable.vue b/components/Timetable.vue
index 2b62efb..c6bfd89 100644
--- a/components/Timetable.vue
+++ b/components/Timetable.vue
@@ -1,5 +1,10 @@
 <template>
-	<figure class="timetable">
+	<figure class="timetable" v-if="schedule.deleted">
+		<p>
+			Error: Schedule is deleted.
+		</p>
+	</figure>
+	<figure class="timetable" v-else>
 		<details>
 			<summary>Debug</summary>
 			<details>
@@ -56,7 +61,7 @@
 				</tr>
 			</thead>
 			<tbody>
-				<template v-for="location in schedule.locations" :key="location.id">
+				<template v-for="location in schedule.locations?.filter(l => !l.deleted)" :key="location.id">
 					<tr v-if="locationRows.has(location.id)">
 						<th>{{ location.name }}</th>
 						<td
@@ -75,7 +80,7 @@
 						<th>Shifts</th>
 						<td :colSpan="totalColumns"></td>
 					</tr>
-					<template v-for="role in schedule.roles" :key="role.id">
+					<template v-for="role in schedule.roles?.filter(r => !r.deleted)" :key="role.id">
 						<tr v-if="roleRows.has(role.id)">
 							<th>{{ role.name }}</th>
 							<td
@@ -97,7 +102,8 @@
 
 <script setup lang="ts">
 import { DateTime } from "luxon";
-import type { Role, Schedule, ScheduleEvent, ScheduleLocation, Shift, ShiftSlot, TimeSlot } from "~/shared/types/schedule";
+import type { ApiSchedule, ApiScheduleEvent, ApiScheduleEventSlot, ApiScheduleLocation, ApiScheduleRole, ApiScheduleShift, ApiScheduleShiftSlot } from "~/shared/types/api";
+import type { Id } from "~/shared/types/common";
 import { pairs, setEquals } from "~/shared/utils/functions";
 
 const oneHourMs = 60 * 60 * 1000;
@@ -107,8 +113,8 @@ const oneMinMs = 60 * 1000;
 
 /** Point in time where a time slots starts or ends. */
 type Edge =
-	| { type: "start" | "end", source: "event", slot: TimeSlot }
-	| { type: "start" | "end", source: "shift", role: string, slot: ShiftSlot }
+	| { type: "start" | "end", source: "event", slot: ApiScheduleEventSlot }
+	| { type: "start" | "end", source: "shift", roleId: Id, slot: ApiScheduleShiftSlot }
 ;
 
 /** Point in time where multiple edges meet. */
@@ -118,8 +124,8 @@ type Junction = { ts: number, edges: Edge[] };
 type Span = {
 	start: Junction;
 	end: Junction,
-	locations: Map<string, Set<TimeSlot>>,
-	roles: Map<string, Set<ShiftSlot>>,
+	locations: Map<number, Set<ApiScheduleEventSlot>>,
+	roles: Map<number, Set<ApiScheduleShiftSlot>>,
 };
 
 /**
@@ -133,7 +139,10 @@ type Stretch = {
 	spans: Span[];
 }
 
-function* edgesFromEvents(events: Iterable<ScheduleEvent>, filter = (slot: TimeSlot) => true): Generator<Edge> {
+function* edgesFromEvents(
+	events: Iterable<Extract<ApiScheduleEvent, { deleted?: false }>>,
+	filter = (slot: ApiScheduleEventSlot) => true,
+): Generator<Edge> {
 	for (const event of events) {
 		for (const slot of event.slots.filter(filter)) {
 			if (slot.start > slot.end) {
@@ -145,14 +154,17 @@ function* edgesFromEvents(events: Iterable<ScheduleEvent>, filter = (slot: TimeS
 	}
 }
 
-function* edgesFromShifts(shifts: Iterable<Shift>, filter = (slot: ShiftSlot) => true): Generator<Edge> {
+function* edgesFromShifts(
+	shifts: Iterable<Extract<ApiScheduleShift, { deleted?: false }>>,
+	filter = (slot: ApiScheduleShiftSlot) => true,
+): Generator<Edge> {
 	for (const shift of shifts) {
 		for (const slot of shift.slots.filter(filter)) {
 			if (slot.start > slot.end) {
 				throw new Error(`Slot ${slot.id} ends before it starts.`);
 			}
-			yield { type: "start", source: "shift", role: shift.role, slot };
-			yield { type: "end", source: "shift", role: shift.role, slot };
+			yield { type: "start", source: "shift", roleId: shift.roleId, slot };
+			yield { type: "end", source: "shift", roleId: shift.roleId, slot };
 		}
 	}
 }
@@ -173,23 +185,25 @@ function junctionsFromEdges(edges: Iterable<Edge>) {
 }
 
 function* spansFromJunctions(
-	junctions: Iterable<Junction>, locations: ScheduleLocation[], roles: Role[] | undefined,
+	junctions: Iterable<Junction>,
+	locations: Extract<ApiScheduleLocation, { deleted?: false }>[],
+	roles: Extract<ApiScheduleRole, { deleted?: false }>[],
 ): Generator<Span> {
 	const activeLocations = new Map(
-		locations.map(location => [location.id, new Set<TimeSlot>()])
+		locations.map(location => [location.id, new Set<ApiScheduleEventSlot>()])
 	);
 	const activeRoles = new Map(
-		roles?.map(role => [role.id, new Set<ShiftSlot>()])
+		roles?.map(role => [role.id, new Set<ApiScheduleShiftSlot>()])
 	);
 	for (const [start, end] of pairs(junctions)) {
 		for (const edge of start.edges) {
 			if (edge.type === "start") {
 				if (edge.source === "event") {
-					for (const location of edge.slot.locations) {
-						activeLocations.get(location)?.add(edge.slot)
+					for (const id of edge.slot.locationIds) {
+						activeLocations.get(id)?.add(edge.slot)
 					}
 				} else if (edge.source === "shift") {
-					activeRoles.get(edge.role)?.add(edge.slot)
+					activeRoles.get(edge.roleId)?.add(edge.slot)
 				}
 			}
 		}
@@ -210,11 +224,11 @@ function* spansFromJunctions(
 		for (const edge of end.edges) {
 			if (edge.type === "end") {
 				if (edge.source === "event") {
-					for (const location of edge.slot.locations) {
-						activeLocations.get(location)?.delete(edge.slot)
+					for (const id of edge.slot.locationIds) {
+						activeLocations.get(id)?.delete(edge.slot)
 					}
 				} else if (edge.source === "shift") {
-					activeRoles.get(edge.role)?.delete(edge.slot);
+					activeRoles.get(edge.roleId)?.delete(edge.slot);
 				}
 			}
 		}
@@ -325,24 +339,24 @@ function padStretch(stretch: Stretch, timezone: string): Stretch {
 
 function tableElementsFromStretches(
 	stretches: Iterable<Stretch>,
-	events: ScheduleEvent[],
-	locations: ScheduleLocation[],
-	rota: Shift[] | undefined,
-	roles: Role[] | undefined,
+	events: Extract<ApiScheduleEvent, { deleted?: false }>[],
+	locations: Extract<ApiScheduleLocation, { deleted?: false }>[],
+	shifts: Extract<ApiScheduleShift, { deleted?: false }>[],
+	roles: Extract<ApiScheduleRole, { deleted?: false }>[],
 	timezone: string,
 ) {
 	type Col = { minutes?: number };
 	type DayHead = { span: number, content?: string }
 	type HourHead = { span: number, content?: string }
-	type LocationCell = { span: number, slots: Set<TimeSlot>, title: string, crew?: boolean }
-	type RoleCell = { span: number, slots: Set<ShiftSlot>, title: string };
+	type LocationCell = { span: number, slots: Set<ApiScheduleEventSlot>, title: string, crew?: boolean }
+	type RoleCell = { span: number, slots: Set<ApiScheduleShiftSlot>, title: string };
 	const columnGroups: { className?: string, cols: Col[] }[] = [];
 	const dayHeaders: DayHead[] = [];
 	const hourHeaders: HourHead[]= [];
-	const locationRows = new Map<string, LocationCell[]>(locations.map(location => [location.id, []]));
-	const roleRows = new Map<string, RoleCell[]>(roles?.map?.(role => [role.id, []]));
+	const locationRows = new Map<number, LocationCell[]>(locations.map(location => [location.id, []]));
+	const roleRows = new Map<number, RoleCell[]>(roles.map(role => [role.id, []]));
 	const eventBySlotId = new Map(events.flatMap(event => event.slots.map(slot => [slot.id, event])));
-	const shiftBySlotId = new Map(rota?.flatMap?.(shift => shift.slots.map(slot =>[slot.id, shift])))
+	const shiftBySlotId = new Map(shifts?.flatMap?.(shift => shift.slots.map(slot =>[slot.id, shift])))
 	let totalColumns = 0;
 
 	function startColumnGroup(className?: string) {
@@ -354,7 +368,7 @@ function tableElementsFromStretches(
 	function startHour(content?: string) {
 		hourHeaders.push({ span: 0, content })
 	}
-	function startLocation(id: string, slots = new Set<TimeSlot>()) {
+	function startLocation(id: number, slots = new Set<ApiScheduleEventSlot>()) {
 		const rows = locationRows.get(id)!;
 		if (rows.length) {
 			const row = rows[rows.length - 1];
@@ -363,7 +377,7 @@ function tableElementsFromStretches(
 		}
 		rows.push({ span: 0, slots, title: "" });
 	}
-	function startRole(id: string, slots = new Set<ShiftSlot>()) {
+	function startRole(id: number, slots = new Set<ApiScheduleShiftSlot>()) {
 		const rows = roleRows.get(id)!;
 		if (rows.length) {
 			const row = rows[rows.length - 1];
@@ -487,21 +501,35 @@ function tableElementsFromStretches(
 }
 
 const props = defineProps<{
-	schedule: Schedule,
-	eventSlotFilter?: (slot: TimeSlot) => boolean,
-	shiftSlotFilter?: (slot: ShiftSlot) => boolean,
+	schedule: ApiSchedule,
+	eventSlotFilter?: (slot: ApiScheduleEventSlot) => boolean,
+	shiftSlotFilter?: (slot: ApiScheduleShiftSlot) => boolean,
 }>();
 const schedule = computed(() => props.schedule);
-const junctions = computed(() => junctionsFromEdges([
-	...edgesFromEvents(schedule.value.events, props.eventSlotFilter),
-	...edgesFromShifts(schedule.value.rota ?? [], props.shiftSlotFilter),
-]));
-const stretches = computed(() => [
-	...stretchesFromSpans(
-		spansFromJunctions(junctions.value, schedule.value.locations, schedule.value.roles),
-		oneHourMs * 5
-	)
-])
+const junctions = computed(() => {
+	if (schedule.value.deleted) {
+		throw Error("Unhandled deleted schedule");
+	}
+	return junctionsFromEdges([
+		...edgesFromEvents(schedule.value.events?.filter(e => !e.deleted) ?? [], props.eventSlotFilter),
+		...edgesFromShifts(schedule.value.shifts?.filter(s => !s.deleted) ?? [], props.shiftSlotFilter),
+	])
+});
+const stretches = computed(() => {
+	if (schedule.value.deleted) {
+		throw Error("Unhandled deleted schedule");
+	}
+	return [
+		...stretchesFromSpans(
+			spansFromJunctions(
+				junctions.value,
+				schedule.value.locations?.filter(l => !l.deleted) ?? [],
+				schedule.value.roles?.filter(r => !r.deleted) ?? [],
+			),
+			oneHourMs * 5
+		)
+	]
+})
 
 const accountStore = useAccountStore();
 const timezone = computed({
@@ -509,9 +537,19 @@ const timezone = computed({
 	set: (value: string) => { accountStore.timezone = value },
 });
 
-const elements = computed(() => tableElementsFromStretches(
-	stretches.value, schedule.value.events, schedule.value.locations, schedule.value.rota, schedule.value.roles, accountStore.activeTimezone
-));
+const elements = computed(() => {
+	if (schedule.value.deleted) {
+		throw Error("Unhandled deleted schedule");
+	}
+	return tableElementsFromStretches(
+		stretches.value,
+		schedule.value.events?.filter(e => !e.deleted) ?? [],
+		schedule.value.locations?.filter(l => !l.deleted) ?? [],
+		schedule.value.shifts?.filter(s => !s.deleted) ?? [],
+		schedule.value.roles?.filter(r => !r.deleted) ?? [],
+		accountStore.activeTimezone
+	);
+});
 const totalColumns = computed(() => elements.value.totalColumns);
 const columnGroups = computed(() => elements.value.columnGroups);
 const dayHeaders = computed(() => elements.value.dayHeaders);
diff --git a/composables/event-source.ts b/composables/event-source.ts
index 924a99c..fbc7c89 100644
--- a/composables/event-source.ts
+++ b/composables/event-source.ts
@@ -1,9 +1,9 @@
-import type { Schedule } from "~/shared/types/schedule";
+import type { ApiEvent } from "~/shared/types/api";
 
 interface AppEventMap {
 	"open": Event,
 	"message": MessageEvent<string>,
-	"update": MessageEvent<Schedule>,
+	"update": MessageEvent<ApiEvent>,
 	"error": Event,
 	"close": Event,
 }
diff --git a/composables/schedule.ts b/composables/schedule.ts
index 497eb88..035c34c 100644
--- a/composables/schedule.ts
+++ b/composables/schedule.ts
@@ -1,5 +1,3 @@
-import type { Schedule } from '~/shared/types/schedule';
-
 export const useSchedule = () => {
 	useEventSource();
 	const schedulesStore = useSchedulesStore();
diff --git a/package.json b/package.json
index 36d42c5..555f5bf 100644
--- a/package.json
+++ b/package.json
@@ -16,7 +16,8 @@
 		"pinia": "^3.0.2",
 		"vue": "latest",
 		"vue-router": "latest",
-		"web-push": "^3.6.7"
+		"web-push": "^3.6.7",
+		"zod": "^3.25.30"
 	},
 	"packageManager": "pnpm@10.5.2+sha512.da9dc28cd3ff40d0592188235ab25d3202add8a207afbedc682220e4a0029ffbff4562102b9e6e46b4e3f9e8bd53e6d05de48544b0c57d4b0179e22c76d1199b",
 	"pnpm": {
diff --git a/pages/edit.vue b/pages/edit.vue
index 71832f1..3c81a19 100644
--- a/pages/edit.vue
+++ b/pages/edit.vue
@@ -1,5 +1,11 @@
 <template>
-	<main>
+	<main v-if="schedule.deleted">
+		<h1>Error</h1>
+		<p>
+			Schedule has been deleted.
+		</p>
+	</main>
+	<main v-else>
 		<h1>Edit</h1>
 		<label>
 			Crew Filter:
@@ -31,7 +37,7 @@
 					:selected="locationFilter === undefined"
 				>&lt;All locations&gt;</option>
 				<option
-					v-for="location in schedule.locations"
+					v-for="location in schedule.locations?.filter(l => !l.deleted)"
 					:key="location.id"
 					:value="location.id"
 					:selected="locationFilter === location.id"
@@ -54,21 +60,21 @@
 					:selected="roleFilter === undefined"
 				>&lt;All roles&gt;</option>
 				<option
-					v-for="role in schedule.roles"
+					v-for="role in schedule.roles?.filter(r => !r.deleted)"
 					:key="role.id"
 					:value="role.id"
 					:selected="roleFilter === role.id"
 				>{{ role.name }}</option>
 			</select>
 		</label>
-		<ShiftScheduleTable :edit="true" :role="roleFilter" :eventSlotFilter :shiftSlotFilter />
+		<ShiftScheduleTable :edit="true" :roleId="roleFilter" :eventSlotFilter :shiftSlotFilter />
 		<h2>Shifts</h2>
-		<ShiftsTable :edit="true" :role="roleFilter" />
+		<ShiftsTable :edit="true" :roleId="roleFilter" />
 	</main>
 </template>
 
 <script lang="ts" setup>
-import type { ShiftSlot, TimeSlot } from '~/shared/types/schedule';
+import type { ApiScheduleEventSlot, ApiScheduleShiftSlot } from '~/shared/types/api';
 
 definePageMeta({
 	middleware: ["authenticated"],
@@ -95,29 +101,29 @@ const eventSlotFilter = computed(() => {
 		return () => true;
 	}
 	const cid = parseInt(crewFilter.value);
-	return (slot: TimeSlot) => slot.assigned?.some(id => id === cid) || false;
+	return (slot: ApiScheduleEventSlot) => slot.assigned?.some(id => id === cid) || false;
 });
 const shiftSlotFilter = computed(() => {
 	if (crewFilter.value === undefined || !accountStore.valid) {
 		return () => true;
 	}
 	const cid = parseInt(crewFilter.value);
-	return (slot: ShiftSlot) => slot.assigned?.some(id => id === cid) || false;
+	return (slot: ApiScheduleShiftSlot) => slot.assigned?.some(id => id === cid) || false;
 });
 
 const locationFilter = computed({
-	get: () => queryToString(route.query.location),
-	set: (value: string | undefined) => navigateTo({
+	get: () => queryToNumber(route.query.location),
+	set: (value: number | undefined) => navigateTo({
 		path: route.path,
 		query: {
 			...route.query,
-			location: value,
+			location: value !== undefined ? String(value) : undefined,
 		},
 	}),
 });
 
 const roleFilter = computed({
-	get: () => queryToString(route.query.role),
+	get: () => queryToNumber(route.query.role),
 	set: (value: string | undefined) => navigateTo({
 		path: route.path,
 		query: {
diff --git a/pages/schedule.vue b/pages/schedule.vue
index 60ac4b5..843ceb7 100644
--- a/pages/schedule.vue
+++ b/pages/schedule.vue
@@ -1,5 +1,11 @@
 <template>
-	<main>
+	<main v-if="schedule.deleted">
+		<h1>Error</h1>
+		<p>
+			Schedule has been deleted.
+		</p>
+	</main>
+	<main v-else>
 		<h1>Schedule & Events</h1>
 		<p>
 			Study carefully, we only hold these events once a year.
@@ -42,10 +48,10 @@
 		</label>
 		<Timetable :schedule :eventSlotFilter :shiftSlotFilter />
 		<h2>Events</h2>
-		<EventCard v-for="event in schedule.events.filter(e => e.slots.some(eventSlotFilter))" :event/>
+		<EventCard v-for="event in schedule.events?.filter(e => !e.deleted && e.slots.some(eventSlotFilter))" :event/>
 		<h2>Locations</h2>
 		<ul>
-			<li v-for="location in schedule.locations" :key="location.id">
+			<li v-for="location in schedule.locations?.filter(l => !l.deleted)" :key="location.id">
 				<h3>{{ location.name }}</h3>
 				{{ location.description ?? "No description provided" }}
 			</li>
@@ -54,7 +60,7 @@
 </template>
 
 <script setup lang="ts">
-import type { ShiftSlot, TimeSlot } from '~/shared/types/schedule';
+import type { ApiScheduleShiftSlot, ApiScheduleEventSlot } from '~/shared/types/api';
 
 const accountStore = useAccountStore();
 const { data: accounts } = await useAccounts();
@@ -73,27 +79,27 @@ const filter = computed({
 });
 
 const eventSlotFilter = computed(() => {
-	if (filter.value === undefined || !accountStore.valid) {
+	if (filter.value === undefined || !accountStore.valid || schedule.value.deleted) {
 		return () => true;
 	}
 	const aid = accountStore.id;
 	if (filter.value === "my-schedule") {
-		const ids = new Set(accountStore.interestedIds);
-		for (const event of schedule.value.events) {
-			if (ids.has(event.id)) {
+		const slotIds = new Set(accountStore.interestedEventSlotIds);
+		for (const event of schedule.value.events ?? []) {
+			if (!event.deleted && accountStore.interestedEventIds.has(event.id)) {
 				for (const slot of event.slots) {
-					ids.add(slot.id);
+					slotIds.add(slot.id);
 				}
 			}
 		}
-		return (slot: TimeSlot) => ids.has(slot.id) || slot.assigned?.some(id => id === aid) || false;
+		return (slot: ApiScheduleEventSlot) => slotIds.has(slot.id) || slot.assigned?.some(id => id === aid) || false;
 	}
 	if (filter.value === "assigned") {
-		return (slot: TimeSlot) => slot.assigned?.some(id => id === aid) || false;
+		return (slot: ApiScheduleEventSlot) => slot.assigned?.some(id => id === aid) || false;
 	}
 	if (filter.value.startsWith("crew-")) {
 		const cid = parseInt(filter.value.slice(5));
-		return (slot: TimeSlot) => slot.assigned?.some(id => id === cid) || false;
+		return (slot: ApiScheduleEventSlot) => slot.assigned?.some(id => id === cid) || false;
 	}
 	return () => false;
 });
@@ -103,11 +109,11 @@ const shiftSlotFilter = computed(() => {
 	}
 	if (filter.value === "my-schedule" || filter.value === "assigned") {
 		const aid = accountStore.id;
-		return (slot: ShiftSlot) => slot.assigned?.some(id => id === aid) || false;
+		return (slot: ApiScheduleShiftSlot) => slot.assigned?.some(id => id === aid) || false;
 	}
 	if (filter.value.startsWith("crew-")) {
 		const cid = parseInt(filter.value.slice(5));
-		return (slot: ShiftSlot) => slot.assigned?.some(id => id === cid) || false;
+		return (slot: ApiScheduleShiftSlot) => slot.assigned?.some(id => id === cid) || false;
 	}
 	return () => false;
 });
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 884bd87..14443d0 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -29,6 +29,9 @@ importers:
       web-push:
         specifier: ^3.6.7
         version: 3.6.7
+      zod:
+        specifier: ^3.25.30
+        version: 3.25.30
     devDependencies:
       '@types/luxon':
         specifier: ^3.4.2
@@ -3498,8 +3501,8 @@ packages:
     resolution: {integrity: sha512-zK7YHHz4ZXpW89AHXUPbQVGKI7uvkd3hzusTdotCg1UxyaVtg0zFJSTfW/Dq5f7OBBVnq6cZIaC8Ti4hb6dtCA==}
     engines: {node: '>= 14'}
 
-  zod@3.25.23:
-    resolution: {integrity: sha512-Od2bdMosahjSrSgJtakrwjMDb1zM1A3VIHCPGveZt/3/wlrTWBya2lmEh2OYe4OIu8mPTmmr0gnLHIWQXdtWBg==}
+  zod@3.25.30:
+    resolution: {integrity: sha512-VolhdEtu6TJr/fzGuHA/SZ5ixvXqA6ADOG9VRcQ3rdOKmF5hkmcJbyaQjUH5BgmpA9gej++zYRX7zjSmdReIwA==}
 
 snapshots:
 
@@ -3929,7 +3932,7 @@ snapshots:
       unixify: 1.0.0
       urlpattern-polyfill: 8.0.2
       yargs: 17.7.2
-      zod: 3.25.23
+      zod: 3.25.30
     transitivePeerDependencies:
       - encoding
       - rollup
@@ -7318,4 +7321,4 @@ snapshots:
       compress-commons: 6.0.2
       readable-stream: 4.7.0
 
-  zod@3.25.23: {}
+  zod@3.25.30: {}
diff --git a/server/api/auth/account.patch.ts b/server/api/auth/account.patch.ts
index 0b3ded2..948392c 100644
--- a/server/api/auth/account.patch.ts
+++ b/server/api/auth/account.patch.ts
@@ -1,39 +1,28 @@
-import { Account } from "~/shared/types/account";
 import { readAccounts, writeAccounts } from "~/server/database";
 import { DateTime } from "luxon";
+import { apiAccountPatchSchema } from "~/shared/types/api";
+import { z } from "zod/v4-mini";
+
 
 export default defineEventHandler(async (event) => {
 	const session = await requireServerSession(event);
-	const body: Pick<Account, "interestedIds" | "timezone"> = await readBody(event);
-	if (
-		body.interestedIds !== undefined
-		&& (
-			!(body.interestedIds instanceof Array)
-			|| !body.interestedIds.every(id => typeof id === "string")
-		)
-	) {
+	const { success, error, data: patch } = apiAccountPatchSchema.safeParse(await readBody(event));
+	if (!success) {
 		throw createError({
 			status: 400,
-			message: "Invalid interestedIds",
+			statusText: "Bad Request",
+			message: z.prettifyError(error),
 		});
 	}
 
-	if (body.timezone !== undefined) {
-		if (typeof body.timezone !== "string") {
+	if (patch.timezone?.length) {
+		const zonedTime = DateTime.local({ locale: "en-US" }).setZone(patch.timezone);
+		if (!zonedTime.isValid) {
 			throw createError({
 				status: 400,
-				message: "Invalid timezone",
+				message: "Invalid timezone: " + zonedTime.invalidExplanation,
 			});
 		}
-		if (body.timezone.length) {
-			const zonedTime = DateTime.local({ locale: "en-US" }).setZone(body.timezone);
-			if (!zonedTime.isValid) {
-				throw createError({
-					status: 400,
-					message: "Invalid timezone: " + zonedTime.invalidExplanation,
-				});
-			}
-		}
 	}
 
 	const accounts = await readAccounts();
@@ -42,16 +31,23 @@ export default defineEventHandler(async (event) => {
 		throw Error("Account does not exist");
 	}
 
-	if (body.interestedIds !== undefined) {
-		if (body.interestedIds.length) {
-			sessionAccount.interestedIds = body.interestedIds;
+	if (patch.interestedEventIds !== undefined) {
+		if (patch.interestedEventIds.length) {
+			sessionAccount.interestedEventIds = patch.interestedEventIds;
 		} else {
-			delete sessionAccount.interestedIds;
+			delete sessionAccount.interestedEventIds;
 		}
 	}
-	if (body.timezone !== undefined) {
-		if (body.timezone)
-			sessionAccount.timezone = body.timezone;
+	if (patch.interestedEventSlotIds !== undefined) {
+		if (patch.interestedEventSlotIds.length) {
+			sessionAccount.interestedEventSlotIds = patch.interestedEventSlotIds;
+		} else {
+			delete sessionAccount.interestedEventSlotIds;
+		}
+	}
+	if (patch.timezone !== undefined) {
+		if (patch.timezone)
+			sessionAccount.timezone = patch.timezone;
 		else
 			delete sessionAccount.timezone;
 	}
diff --git a/server/api/auth/account.post.ts b/server/api/auth/account.post.ts
index 6603a4e..90ff820 100644
--- a/server/api/auth/account.post.ts
+++ b/server/api/auth/account.post.ts
@@ -1,5 +1,5 @@
 import { readAccounts, writeAccounts, nextAccountId } from "~/server/database";
-import { Account } from "~/shared/types/account";
+import type { ApiAccount } from "~/shared/types/api";
 
 export default defineEventHandler(async (event) => {
 	let session = await getServerSession(event);
@@ -14,7 +14,7 @@ export default defineEventHandler(async (event) => {
 	const name = formData.get("name");
 
 	const accounts = await readAccounts();
-	let account: Account;
+	let account: ApiAccount;
 	if (typeof name === "string") {
 		if (name === "") {
 			throw createError({
diff --git a/server/api/auth/session.get.ts b/server/api/auth/session.get.ts
index 03c1d43..74ca737 100644
--- a/server/api/auth/session.get.ts
+++ b/server/api/auth/session.get.ts
@@ -1,7 +1,7 @@
 import { readAccounts, readSubscriptions } from "~/server/database";
-import { AccountSession } from "~/shared/types/account";
+import type { ApiSession } from "~/shared/types/api";
 
-export default defineEventHandler(async (event): Promise<AccountSession | undefined> => {
+export default defineEventHandler(async (event): Promise<ApiSession | undefined> => {
 	const session = await getServerSession(event);
 	if (!session)
 		return;
diff --git a/server/api/schedule.patch.ts b/server/api/schedule.patch.ts
index 4401168..26c2fee 100644
--- a/server/api/schedule.patch.ts
+++ b/server/api/schedule.patch.ts
@@ -1,41 +1,8 @@
-import type { SchedulePatch } from "~/shared/types/schedule";
+import { z } from "zod/v4-mini";
 import { readAccounts, readSchedule, writeSchedule } from "~/server/database";
-import { broadcastUpdate } from "~/server/streams";
-import { applyChangeArray } from "~/shared/utils/changes";
-
-function isChange(change: unknown) {
-	return (
-		typeof change === "object"
-		&& change !== null
-		&& "op" in change
-		&& (
-			change.op === "set" || change.op === "del"
-		)
-		&& "data" in change
-		&& typeof change.data === "object"
-		&& change.data !== null
-		&& "id" in change.data
-		&& typeof change.data.id === "string"
-	)
-}
-
-function isChangeArray(data: unknown) {
-	return data instanceof Array && data.every(item => isChange(item));
-}
-
-function isPatch(data: unknown): SchedulePatch {
-	if (
-		typeof data !== "object"
-		|| data === null
-		|| data instanceof Array
-		|| "locations" in data && !isChangeArray(data.locations)
-		|| "events" in data && !isChangeArray(data.events)
-		|| "roles" in data && !isChangeArray(data.roles)
-		|| "rota" in data && !isChangeArray(data.rota)
-	)
-		throw new Error("Invalid patch data")
-	return data // TODO: Actually validate the whole structure with e.g ajv or zod
-}
+import { broadcastEvent } from "~/server/streams";
+import { apiScheduleSchema } from "~/shared/types/api";
+import { applyUpdatesToArray } from "~/shared/utils/update";
 
 export default defineEventHandler(async (event) => {
 	const session = await requireServerSession(event);
@@ -53,22 +20,43 @@ export default defineEventHandler(async (event) => {
 		});
 	}
 
+	const { success, error, data: update } = apiScheduleSchema.safeParse(await readBody(event));
+	if (!success) {
+		throw createError({
+			status: 400,
+			statusText: "Bad Request",
+			message: z.prettifyError(error),
+		});
+	}
+
+	if (update.deleted) {
+		throw createError({
+			statusCode: 400,
+			statusMessage: "Not implemented",
+		});
+	}
+
 	const schedule = await readSchedule();
-	const patch = await readValidatedBody(event, isPatch);
+
+	if (schedule.deleted) {
+		throw createError({
+			statusCode: 400,
+			statusMessage: "Not implemented",
+		});
+	}
 
 	// Validate edit restrictions for crew
 	if (account.type === "crew") {
-		if (patch.locations?.length) {
+		if (update.locations?.length) {
 			throw createError({
 				status: 403,
 				statusMessage: "Forbidden",
 				message: "Only admin accounts can edit locations.",
 			});
 		}
-		for (const event of patch.events ?? []) {
-			const id = event.op === "set" ? event.data.id : event.id;
-			const original = schedule.events.find(e => e.id === id);
-			if (original && !original.crew) {
+		for (const event of update.events ?? []) {
+			const original = schedule.events?.find(e => e.id === event.id);
+			if (original && !original.deleted && !original.crew) {
 				throw createError({
 					status: 403,
 					statusMessage: "Forbidden",
@@ -78,11 +66,30 @@ export default defineEventHandler(async (event) => {
 		}
 	}
 
-	if (patch.events) applyChangeArray(patch.events, schedule.events);
-	if (patch.locations) applyChangeArray(patch.locations, schedule.locations);
-	if (patch.roles) applyChangeArray(patch.roles, schedule.roles = schedule.roles ?? []);
-	if (patch.rota) applyChangeArray(patch.rota, schedule.rota = schedule.rota ?? []);
+	// Update schedule
+	const updatedFrom = schedule.updatedAt;
+	update.updatedAt = new Date().toISOString();
+	if (update.events) {
+		for (const event of update.events) event.updatedAt = update.updatedAt;
+		applyUpdatesToArray(update.events, schedule.events = schedule.events ?? []);
+	}
+	if (update.locations) {
+		for (const location of update.locations) location.updatedAt = update.updatedAt;
+		applyUpdatesToArray(update.locations, schedule.locations = schedule.locations ?? []);
+	}
+	if (update.roles) {
+		for (const role of update.roles) role.updatedAt = update.updatedAt;
+		applyUpdatesToArray(update.roles, schedule.roles = schedule.roles ?? []);
+	}
+	if (update.shifts) {
+		for (const shift of update.shifts) shift.updatedAt = update.updatedAt;
+		applyUpdatesToArray(update.shifts, schedule.shifts = schedule.shifts ?? []);
+	}
 
 	await writeSchedule(schedule);
-	await broadcastUpdate(schedule);
+	await broadcastEvent({
+		type: "schedule-update",
+		updatedFrom,
+		data: update,
+	});
 })
diff --git a/server/api/schedule.ts b/server/api/schedule.ts
index 33dc8dc..fa0e6c9 100644
--- a/server/api/schedule.ts
+++ b/server/api/schedule.ts
@@ -1,14 +1,14 @@
 import { readAccounts, readSchedule } from "~/server/database";
-import { Account } from "~/shared/types/account";
+import type { ApiAccount } from "~/shared/types/api";
 import { canSeeCrew } from "../utils/schedule";
 
 export default defineEventHandler(async (event) => {
 	const session = await getServerSession(event);
-	let account: Account | undefined;
+	let account: ApiAccount | undefined;
 	if (session) {
 		const accounts = await readAccounts()
 		account = accounts.find(account => account.id === session.accountId);
 	}
 	const schedule = await readSchedule();
 	return canSeeCrew(account?.type) ? schedule : filterSchedule(schedule);
-})
+});
diff --git a/server/api/subscribe.post.ts b/server/api/subscribe.post.ts
index 4d04fe0..a5594f4 100644
--- a/server/api/subscribe.post.ts
+++ b/server/api/subscribe.post.ts
@@ -1,14 +1,26 @@
 import { readSubscriptions, writeSubscriptions } from "~/server/database";
-import { Subscription } from "~/shared/types/account";
+import { type ApiSubscription, apiSubscriptionSchema } from "~/shared/types/api";
+import { z } from "zod/v4-mini";
+
+const subscriptionSchema = z.strictObject({
+	subscription: apiSubscriptionSchema.def.shape.push,
+});
 
 export default defineEventHandler(async (event) => {
 	const session = await requireServerSession(event);
-	const body: { subscription: PushSubscriptionJSON } = await readBody(event);
+	const { success, error, data: body } = subscriptionSchema.safeParse(await readBody(event));
+	if (!success) {
+		throw createError({
+			status: 400,
+			statusText: "Bad Request",
+			message: z.prettifyError(error),
+		});
+	}
 	const subscriptions = await readSubscriptions();
 	const existingIndex = subscriptions.findIndex(
 		sub => sub.type === "push" && sub.sessionId === session.id
 	);
-	const subscription: Subscription = {
+	const subscription: ApiSubscription = {
 		type: "push",
 		sessionId: session.id,
 		push: body.subscription
diff --git a/server/database.ts b/server/database.ts
index aebc4d1..b43bddc 100644
--- a/server/database.ts
+++ b/server/database.ts
@@ -1,6 +1,5 @@
 import { readFile, unlink, writeFile } from "node:fs/promises";
-import { Schedule } from "~/shared/types/schedule";
-import { Account, Subscription } from "~/shared/types/account";
+import type { ApiAccount, ApiSchedule, ApiSubscription } from "~/shared/types/api";
 import { generateDemoSchedule, generateDemoAccounts } from "./generate-demo-schedule";
 
 export interface ServerSession {
@@ -51,12 +50,12 @@ export async function readSchedule() {
 	return readJson(schedulePath, generateDemoSchedule);
 }
 
-export async function writeSchedule(schedule: Schedule) {
+export async function writeSchedule(schedule: ApiSchedule) {
 	await writeFile(schedulePath, JSON.stringify(schedule, undefined, "\t") + "\n", "utf-8");
 }
 
 export async function readSubscriptions() {
-	let subscriptions = await readJson<Subscription[]>(subscriptionsPath, []);
+	let subscriptions = await readJson<ApiSubscription[]>(subscriptionsPath, []);
 	if (subscriptions.length && "keys" in subscriptions[0]) {
 		// Discard old format
 		subscriptions = [];
@@ -64,7 +63,7 @@ export async function readSubscriptions() {
 	return subscriptions;
 }
 
-export async function writeSubscriptions(subscriptions: Subscription[]) {
+export async function writeSubscriptions(subscriptions: ApiSubscription[]) {
 	await writeFile(subscriptionsPath, JSON.stringify(subscriptions, undefined, "\t") + "\n", "utf-8");
 }
 
@@ -81,7 +80,7 @@ export async function readAccounts() {
 	return await readJson(accountsPath, generateDemoAccounts);
 }
 
-export async function writeAccounts(accounts: Account[]) {
+export async function writeAccounts(accounts: ApiAccount[]) {
 	await writeFile(accountsPath, JSON.stringify(accounts, undefined, "\t") + "\n", "utf-8");
 }
 
diff --git a/server/generate-demo-schedule.ts b/server/generate-demo-schedule.ts
index 7c35e3a..a75a165 100644
--- a/server/generate-demo-schedule.ts
+++ b/server/generate-demo-schedule.ts
@@ -1,30 +1,41 @@
-import { Account } from "~/shared/types/account";
-import { Role, Schedule, Shift, ShiftSlot, TimeSlot } from "~/shared/types/schedule";
+import type { ApiAccount, ApiSchedule, ApiScheduleEventSlot, ApiScheduleShiftSlot } from "~/shared/types/api";
 import { toId } from "~/shared/utils/functions";
 
 const locations = [
 	{
+		id: 1,
 		name: "Stage",
-		description: "Inside the main building."
+		description: "Inside the main building.",
+		updatedAt: "d0 18:21",
 	},
 	{
+		id: 2,
 		name: "Clubhouse",
-		description: "That big red building in the middle of the park."
+		description: "That big red building in the middle of the park.",
+		updatedAt: "d0 18:25",
 	},
 	{
+		id: 4,
 		name: "Summerhouse",
-		description: "Next to the campfire by the lake"
+		description: "Next to the campfire by the lake",
+		updatedAt: "d0 18:22",
 	},
 	{
+		id: 6,
 		name: "Campfire",
-		description: "Next to the big tree by the lake."
+		description: "Next to the big tree by the lake.",
+		updatedAt: "d0 18:41",
 	},
 	{
+		id: 7,
 		name: "Outside",
-		description: "Takes place somewhere outside."
+		description: "Takes place somewhere outside.",
+		updatedAt: "d0 18:37",
 	}
 ]
 
+let slotId = 1;
+let eventId = 1;
 const events = [
 	{
 		name: "Arcade",
@@ -133,17 +144,24 @@ const events = [
 	{ name: "Artist Alley", slots: ["d4 12:00 4h clubhouse"]},
 	{ name: "Teardown Artist Alley", crew: true, slots: ["d4 16:00 1h clubhouse"]},
 	{ name: "Feedback Panel", slots: ["d5 12:00 1h clubhouse"]},
-];
+].map(({ slots, ...rest }) => ({
+	...rest,
+	id: eventId++,
+	slots: slots.map(slot => `${slot} ${slotId++}`),
+}));
 
-const roles: Role[] = [
-	{ id: "medic", name: "Medic" },
-	{ id: "security", name: "Security" },
+
+const idMedic = 1;
+const idSecurity = 2;
+const roles = [
+	{ id: idMedic, name: "Medic", updatedAt: "d1 12:34" },
+	{ id: idSecurity, name: "Security", updatedAt: "d1 12:39" },
 ]
 
-const rota = [
+const shifts = [
 	{
 		name: "Medic Early",
-		role: "medic",
+		roleId: idMedic,
 		slots: [
 			"d1 12:00 4h",
 			"d2 12:00 4h",
@@ -154,7 +172,7 @@ const rota = [
 	},
 	{
 		name: "Medic Late",
-		role: "medic",
+		roleId: idMedic,
 		slots: [
 			"d1 16:00 7h",
 			"d2 16:00 6h",
@@ -164,7 +182,7 @@ const rota = [
 	},
 	{
 		name: "Security Early",
-		role: "security",
+		roleId: idSecurity,
 		slots: [
 			"d1 12:00 6h",
 			"d2 12:00 6h",
@@ -175,7 +193,7 @@ const rota = [
 	},
 	{
 		name: "Security Late",
-		role: "security",
+		roleId: idSecurity,
 		slots: [
 			"d1 18:00 5h",
 			"d2 18:00 4h",
@@ -183,13 +201,17 @@ const rota = [
 			"d4 18:00 5h",
 		],
 	},
-]
+].map(({ slots, ...rest }) => ({
+	...rest,
+	id: eventId++,
+	slots: slots.map(slot => `${slot} ${slotId++}`),
+}));
 
 function toIso(date: Date) {
 	return date.toISOString().replace(":00.000Z", "Z");
 }
 
-function toDates(origin: Date, day: string, start: string, duration: string) {
+function toDate(origin: Date, day: string, start: string) {
 	const [startHours, startMinutes] = start.split(":").map(time => parseInt(time, 10));
 	const dayNumber = parseInt(day.slice(1));
 
@@ -198,6 +220,11 @@ function toDates(origin: Date, day: string, start: string, duration: string) {
 	startDate.setUTCHours(startDate.getUTCHours() + startHours);
 	startDate.setUTCMinutes(startDate.getUTCMinutes() + startMinutes);
 
+	return startDate;
+}
+
+function toDates(origin: Date, day: string, start: string, duration: string) {
+	const startDate = toDate(origin, day, start);
 	const [_, durationHours, durationMinutes] = /(?:(\d+)h)?(?:(\d+)m)?/.exec(duration)!;
 	const durationTotal = parseInt(durationHours ?? "0") * 60 + parseInt(durationMinutes ?? "0")
 	const endDate = new Date(startDate.getTime() + durationTotal * 60e3);
@@ -205,33 +232,35 @@ function toDates(origin: Date, day: string, start: string, duration: string) {
 	return [startDate, endDate];
 }
 
-function toSlot(origin: Date, id: string, shorthand: string, index: number, counts: Map<string, number>, idToAssigned: Map<string, number[]>): TimeSlot {
-	const [day, start, duration, location] = shorthand.split(" ");
+function toSlot(origin: Date, shorthand: string, counts: Map<number, number>, idToAssigned: Map<number, number[]>): ApiScheduleEventSlot {
+	const [day, start, duration, location, idStr] = shorthand.split(" ");
 	const [startDate, endDate] = toDates(origin, day, start, duration);
+	const id = parseInt(idStr, 10);
 
 	return {
-		id: `${id}-${index}`,
+		id,
 		start: toIso(startDate),
 		end: toIso(endDate),
-		locations: [location],
-		assigned: idToAssigned.get(`${id}-${index}`),
-		interested: counts.get(`${id}-${index}`),
+		locationIds: [locations.find(l => toId(l.name) === location)!.id],
+		assigned: idToAssigned.get(id),
+		interested: counts.get(id),
 	};
 }
 
-function toShift(origin: Date, id: string, shorthand: string, index: number, idToAssigned: Map<string, number[]>): ShiftSlot {
-	const [day, start, duration] = shorthand.split(" ");
+function toShift(origin: Date, shorthand: string, idToAssigned: Map<number, number[]>): ApiScheduleShiftSlot {
+	const [day, start, duration, idStr] = shorthand.split(" ");
 	const [startDate, endDate] = toDates(origin, day, start, duration);
+	const id = parseInt(idStr, 10);
 
 	return {
-		id: `${id}-${index}`,
+		id,
 		start: toIso(startDate),
 		end: toIso(endDate),
-		assigned: idToAssigned.get(`${id}-${index}`),
+		assigned: idToAssigned.get(id),
 	};
 }
 
-export function generateDemoSchedule(): Schedule {
+export function generateDemoSchedule(): ApiSchedule {
 	const origin = new Date();
 	const utcOffset = 1;
 	origin.setUTCDate(origin.getUTCDate() - origin.getUTCDay() + 1); // Go to Monday
@@ -240,101 +269,98 @@ export function generateDemoSchedule(): Schedule {
 	origin.setUTCSeconds(0);
 	origin.setUTCMilliseconds(0);
 
-	const counts = new Map<string, number>()
+	const eventCounts = new Map<number, number>()
+	const slotCounts = new Map<number, number>()
 	const accounts = generateDemoAccounts();
 	for (const account of accounts) {
-		for (const id of account.interestedIds ?? []) {
-			counts.set(id, (counts.get(id) ?? 0) + 1);
+		for (const id of account.interestedEventIds ?? []) {
+			eventCounts.set(id, (eventCounts.get(id) ?? 0) + 1);
+		}
+		for (const id of account.interestedEventSlotIds ?? []) {
+			slotCounts.set(id, (slotCounts.get(id) ?? 0) + 1);
 		}
 	}
 
-	seed = 2;
-	const idToAssigned = new Map<string, number[]>();
-	for (const account of accounts.filter(a => a.type === "crew" || a.type === "admin")) {
-		const assignedIds: string[] = [];
-		const slotsToAdd = Math.floor(random() * 20);
-		while (assignedIds.length < slotsToAdd) {
-			const event = events[Math.floor(random() * events.length)];
-			const eventId = toId(event.name);
-			if (assignedIds.some(id => id.replace(/-\d+$/, "") === eventId)) {
-				continue;
-			}
-			if (event.slots.length === 1 || random() < 0.8) {
-				for (const index of event.slots.map((_, index) => index)) {
-					assignedIds.push(toId(`${toId(event.name)}-${index}`));
+	function assignSlots(events: { id: number, slots: string[] }[], count: number) {
+		const idToAssigned = new Map<number, number[]>();
+		for (const account of accounts.filter(a => a.type === "crew" || a.type === "admin")) {
+			const assignedIds = new Set<number>;
+			const usedEvents = new Set<number>;
+			const slotsToAdd = Math.floor(random() * count);
+			while (assignedIds.size < slotsToAdd) {
+				const event = events[Math.floor(random() * events.length)];
+				if (usedEvents.has(event.id)) {
+					continue;
 				}
-			} else {
-				for (const index of event.slots.map((_, index) => index)) {
-					if (random() < 0.5) {
-						assignedIds.push(toId(`${toId(event.name)}-${index}`));
+				if (event.slots.length === 1 || random() < 0.8) {
+					for (const slot of event.slots) {
+						const id = parseInt(slot.split(" ").slice(-1)[0]);
+						assignedIds.add(id);
+						usedEvents.add(event.id);
+					}
+				} else {
+					for (const slot of event.slots) {
+						if (random() < 0.5) {
+							const id = parseInt(slot.split(" ").slice(-1)[0]);
+							assignedIds.add(id);
+							usedEvents.add(event.id);
+						}
 					}
 				}
 			}
-		}
-		for (const id of assignedIds) {
-			const assigned = idToAssigned.get(id);
-			if (assigned) {
-				assigned.push(account.id);
-			} else {
-				idToAssigned.set(id, [account.id]);
+			for (const id of assignedIds) {
+				const assigned = idToAssigned.get(id);
+				if (assigned) {
+					assigned.push(account.id);
+				} else {
+					idToAssigned.set(id, [account.id]);
+				}
 			}
 		}
+		return idToAssigned;
 	}
+	seed = 2;
+	const eventSlotIdToAssigned = assignSlots(events, 20);
 
 	seed = 5;
-	for (const account of accounts.filter(a => a.type === "crew" || a.type === "admin")) {
-		const assignedIds: string[] = [];
-		const slotsToAdd = Math.floor(random() * 3);
-		while (assignedIds.length < slotsToAdd) {
-			const shift = rota[Math.floor(random() * rota.length)];
-			const shiftId = toId(shift.name);
-			if (assignedIds.some(id => id.replace(/-\d+$/, "") === shiftId)) {
-				continue;
-			}
-			if (shift.slots.length === 1 || random() < 0.8) {
-				for (const index of shift.slots.map((_, index) => index)) {
-					assignedIds.push(toId(`${toId(shift.name)}-${index}`));
-				}
-			} else {
-				for (const index of shift.slots.map((_, index) => index)) {
-					if (random() < 0.5) {
-						assignedIds.push(toId(`${toId(shift.name)}-${index}`));
-					}
-				}
-			}
-		}
-		for (const id of assignedIds) {
-			const assigned = idToAssigned.get(id);
-			if (assigned) {
-				assigned.push(account.id);
-			} else {
-				idToAssigned.set(id, [account.id]);
-			}
-		}
-	}
-
+	const shiftSlotIdToAssigned = assignSlots(shifts, 3);
 
 	return {
+		id: 111,
+		updatedAt: toIso(toDate(origin, "d2", "10:01")),
 		events: events.map(
-			({ name, crew, description, slots }) => ({
-				id: toId(name),
+			({ id, name, crew, description, slots }) => ({
+				id,
 				name,
 				crew,
 				description,
-				interested: counts.get(toId(name)),
-				slots: slots.map((shorthand, index) => toSlot(origin, toId(name), shorthand, index, counts, idToAssigned))
+				interested: eventCounts.get(id),
+				slots: slots.map(shorthand => toSlot(origin, shorthand, slotCounts, eventSlotIdToAssigned)),
+				updatedAt: toIso(toDate(origin, "d0", "15:11")),
 			})
 		),
 		locations: locations.map(
-			({ name, description }) => ({ id: toId(name), name, description })
-		),
-		roles,
-		rota: rota.map(
-			({ name, role, slots }) => ({
-				id: toId(name),
+			({ id, name, description, updatedAt }) => ({
+				id,
 				name,
-				role,
-				slots: slots.map((shorthand, index) => toShift(origin, toId(name), shorthand, index, idToAssigned))
+				description,
+				updatedAt: toIso(toDate(origin, ...(updatedAt.split(" ")) as [string, string])),
+			})
+		),
+		roles: roles.map(
+			({ id, name, updatedAt }) => ({
+				id,
+				name,
+				updatedAt: toIso(toDate(origin, ...(updatedAt.split(" ")) as [string, string])),
+			})
+		),
+		shifts: shifts.map(
+			({ id, name, roleId, slots }) => ({
+				id,
+				name,
+				roleId,
+				slots: slots.map(shorthand => toShift(origin, shorthand, shiftSlotIdToAssigned)),
+				updatedAt: toIso(toDate(origin, "d0", "13:23")),
 			})
 		)
 	};
@@ -364,9 +390,9 @@ function random() {
 	return (seed = (a * seed + c) % m | 0) / 2 ** 31;
 }
 
-export function generateDemoAccounts(): Account[] {
+export function generateDemoAccounts(): ApiAccount[] {
 	seed = 1;
-	const accounts: Account[] = [];
+	const accounts: ApiAccount[] = [];
 
 	for (const name of names) {
 		accounts.push({
@@ -378,38 +404,45 @@ export function generateDemoAccounts(): Account[] {
 
 	seed = 1;
 	// These have a much higher probability of being in someone's interested list.
-	const desiredEvent = ["opening", "closing", "fursuit-games"];
+	const desiredEvent = ["opening", "closing", "fursuit-games"].map(
+		id => events.find(e => toId(e.name) === id)!.id
+	);
 	const nonCrewEvents = events.filter(event => !event.crew);
 
 	for (const account of accounts) {
-		const interestedIds: string[] = [];
+		const interestedEventIds = new Set<number>;
+		const interestedSlotIds = new Set<number>;
+		const usedEvents = new Set<number>;
 		for (const id of desiredEvent) {
 			if (random() < 0.5) {
-				interestedIds.push(id);
+				interestedEventIds.add(id);
 			}
 		}
 
 		const eventsToAdd = Math.floor(random() * 10);
-		while (interestedIds.length < eventsToAdd) {
+		while (interestedEventIds.size + interestedSlotIds.size < eventsToAdd) {
 			const event = nonCrewEvents[Math.floor(random() * nonCrewEvents.length)];
-			const eventId = toId(event.name);
-			if (interestedIds.some(id => id.replace(/-\d+$/, "") === eventId)) {
+			if (usedEvents.has(event.id)) {
 				continue;
 			}
 
 			if (event.slots.length === 1 || random() < 0.8) {
-				interestedIds.push(toId(event.name))
+				interestedEventIds.add(event.id)
 			} else {
-				for (const index of event.slots.map((_, index) => index)) {
+				for (const slot of event.slots) {
 					if (random() < 0.5) {
-						interestedIds.push(toId(`${toId(event.name)}-${index}`));
+						const id = parseInt(slot.split(" ")[4], 10);
+						interestedSlotIds.add(id);
 					}
 				}
 			}
 		}
 
-		if (interestedIds.length) {
-			account.interestedIds = interestedIds;
+		if (interestedEventIds.size) {
+			account.interestedEventIds = [...interestedEventIds];
+		}
+		if (interestedSlotIds.size) {
+			account.interestedEventSlotIds = [...interestedSlotIds];
 		}
 	}
 	return accounts;
diff --git a/server/streams.ts b/server/streams.ts
index 867fa1e..82c2488 100644
--- a/server/streams.ts
+++ b/server/streams.ts
@@ -1,6 +1,6 @@
-import { Schedule } from "~/shared/types/schedule"
 import { readAccounts } from "~/server/database";
 import { canSeeCrew } from "./utils/schedule";
+import type { ApiAccount, ApiEvent } from "~/shared/types/api";
 
 function sendMessage(
 	stream: WritableStream<string>,
@@ -65,22 +65,58 @@ export function cancelSessionStreams(sessionId: number) {
 	}
 }
 
-export async function broadcastUpdate(schedule: Schedule) {
+const encodeEventCache = new WeakMap<ApiEvent, Map<ApiAccount["type"] | undefined, string>>();
+function encodeEvent(event: ApiEvent, accountType: ApiAccount["type"] | undefined) {
+	const cache = encodeEventCache.get(event);
+	const cacheEntry = cache?.get(accountType);
+	if (cacheEntry) {
+		return cacheEntry;
+	}
+
+	let data: string;
+	if (event.type === "schedule-update") {
+		if (!canSeeCrew(accountType)) {
+			event = {
+				type: event.type,
+				updatedFrom: event.updatedFrom,
+				data: filterSchedule(event.data),
+			};
+		}
+		data = JSON.stringify(event);
+	} else {
+		throw Error(`encodeEvent cannot encode ${event.type} event`);
+	}
+
+	if (cache) {
+		cache.set(accountType, data);
+	} else {
+		encodeEventCache.set(event, new Map([[accountType, data]]));
+	}
+	return data;
+}
+
+export async function broadcastEvent(event: ApiEvent) {
 	const id = Date.now();
 	console.log(`broadcasting update to ${streams.size} clients`);
 	if (!streams.size) {
 		return;
 	}
 	const accounts = await readAccounts();
-	const filteredSchedule = filterSchedule(schedule);
 	for (const [stream, streamData] of streams) {
-		let accountType: string | undefined;
-		if (streamData.accountId !== undefined) {
-			accountType = accounts.find(a => a.id === streamData.accountId)?.type
+		// Account events are specially handled and only sent to the account they belong to.
+		if (event.type === "account-update") {
+			if (streamData.accountId === event.data.id) {
+				sendMessage(stream, `id: ${id}\nevent: update\ndata: ${JSON.stringify(event)}\n\n`);
+			}
+
+		} else {
+			let accountType: ApiAccount["type"] | undefined;
+			if (streamData.accountId !== undefined) {
+				accountType = accounts.find(a => a.id === streamData.accountId)?.type
+			}
+			const data = encodeEvent(event, accountType)
+			sendMessage(stream, `id: ${id}\nevent: update\ndata: ${data}\n\n`);
 		}
-		const data = JSON.stringify(canSeeCrew(accountType) ? schedule : filteredSchedule);
-		const message = `id: ${id}\nevent: update\ndata: ${data}\n\n`
-		sendMessage(stream, message);
 	}
 }
 
diff --git a/server/utils/schedule.ts b/server/utils/schedule.ts
index 7e1f1dc..2e6d5d0 100644
--- a/server/utils/schedule.ts
+++ b/server/utils/schedule.ts
@@ -1,24 +1,61 @@
-import { Account } from '~/shared/types/account';
-import { Schedule } from '~/shared/types/schedule';
 import { readSchedule, writeSchedule } from '~/server/database';
-import { broadcastUpdate } from '~/server/streams';
+import { broadcastEvent } from '~/server/streams';
+import type { ApiAccount, ApiSchedule } from '~/shared/types/api';
 
-export async function updateScheduleInterestedCounts(accounts: Account[]) {
-	const counts = new Map();
-	for (const account of accounts)
-		if (account.interestedIds)
-			for (const id of account.interestedIds)
-				counts.set(id, (counts.get(id) ?? 0) + 1);
+export async function updateScheduleInterestedCounts(accounts: ApiAccount[]) {
+	const eventCounts = new Map<number, number>();
+	const eventSlotCounts = new Map<number, number>();
+	for (const account of accounts) {
+		if (account.interestedEventIds)
+			for (const id of account.interestedEventIds)
+				eventCounts.set(id, (eventCounts.get(id) ?? 0) + 1);
+		if (account.interestedEventSlotIds)
+			for (const id of account.interestedEventSlotIds)
+				eventSlotCounts.set(id, (eventSlotCounts.get(id) ?? 0) + 1);
+	}
 
 	const schedule = await readSchedule();
-	for (const event of schedule.events) {
-		event.interested = counts.get(event.id);
+	if (schedule.deleted) {
+		throw new Error("Deleted schedule not implemented");
+	}
+	const update: ApiSchedule = {
+		id: schedule.id,
+		updatedAt: new Date().toISOString(),
+		events: [],
+	};
+	const updatedFrom = schedule.updatedAt;
+	for (const event of schedule.events ?? []) {
+		let modified = false;
+		if (event.deleted)
+			continue;
+
+		let count = eventCounts.get(event.id);
+		if (count !== event.interested) {
+			event.interested = eventCounts.get(event.id);
+			modified = true;
+		}
 		for (const slot of event.slots) {
-			slot.interested = counts.get(slot.id);
+			let slotCount = eventSlotCounts.get(slot.id);
+			if (slotCount !== slot.interested) {
+				slot.interested = slotCount;
+				modified = true;
+			}
+		}
+		if (modified) {
+			event.updatedAt = update.updatedAt;
+			update.events!.push(event);
 		}
 	}
+	if (!update.events!.length) {
+		return; // No changes
+	}
+	schedule.updatedAt = updatedFrom;
 	await writeSchedule(schedule);
-	await broadcastUpdate(schedule);
+	await broadcastEvent({
+		type: "schedule-update",
+		updatedFrom,
+		data: update,
+	});
 }
 
 export function canSeeCrew(accountType: string | undefined) {
@@ -26,17 +63,28 @@ export function canSeeCrew(accountType: string | undefined) {
 }
 
 /** Filters out crew visible only parts of schedule */
-export function filterSchedule(schedule: Schedule): Schedule {
+export function filterSchedule(schedule: ApiSchedule): ApiSchedule {
+	if (schedule.deleted) {
+		return schedule;
+	}
 	return {
+		id: schedule.id,
+		updatedAt: schedule.updatedAt,
 		locations: schedule.locations,
-		events: schedule.events
-			.filter(event => !event.crew)
-			.map(event => ({
-				...event,
-				slots: event.slots.map(slot => ({
-					...slot,
-					assigned: undefined,
-				})),
+		events: (schedule.events ?? [])
+			.map(event => (
+				event.deleted
+					? event
+					: event.crew
+						// Pretend crew events are deleted.
+						? { id: event.id, deleted: true, updatedAt: event.updatedAt }
+						: {
+							...event,
+							slots: event.slots.map(slot => ({
+								...slot,
+								assigned: undefined,
+						}
+				)),
 			})),
 	}
 }
diff --git a/server/utils/session.ts b/server/utils/session.ts
index 51c0423..29ea6de 100644
--- a/server/utils/session.ts
+++ b/server/utils/session.ts
@@ -1,5 +1,5 @@
 import type { H3Event } from "h3";
-import { nextSessionId, readSessions, readSubscriptions, ServerSession, writeSessions, writeSubscriptions } from "~/server/database";
+import { nextSessionId, readSessions, readSubscriptions, type ServerSession, writeSessions, writeSubscriptions } from "~/server/database";
 
 const oneYearSeconds = 365 * 24 * 60 * 60;
 
diff --git a/shared/types/account.d.ts b/shared/types/account.d.ts
deleted file mode 100644
index 8662628..0000000
--- a/shared/types/account.d.ts
+++ /dev/null
@@ -1,25 +0,0 @@
-export interface Account {
-	id: number,
-	type: "anonymous" | "regular" | "crew" | "admin",
-	/** Name of the account. Not present on anonymous accounts */
-	name?: string,
-	interestedIds?: string[],
-	timezone?: string,
-}
-
-export interface Subscription {
-	type: "push",
-	sessionId: number,
-	push: PushSubscriptionJSON,
-}
-
-export interface Session {
-	id: number,
-	accountId: number,
-}
-
-export interface AccountSession {
-	id: number,
-	account: Account,
-	push: boolean,
-}
diff --git a/shared/types/api.ts b/shared/types/api.ts
new file mode 100644
index 0000000..9ff31bc
--- /dev/null
+++ b/shared/types/api.ts
@@ -0,0 +1,111 @@
+import { z } from "zod/v4-mini";
+import { defineEntity, idSchema, type Id } from "~/shared/types/common";
+
+export interface ApiAccount {
+	id: Id,
+	type: "anonymous" | "regular" | "crew" | "admin",
+	/** Name of the account. Not present on anonymous accounts */
+	name?: string,
+	interestedEventIds?: number[],
+	interestedEventSlotIds?: number[],
+	timezone?: string,
+}
+
+export const apiAccountPatchSchema = z.object({
+	name: z.optional(z.string()),
+	interestedEventIds: z.optional(z.array(z.number())),
+	interestedEventSlotIds: z.optional(z.array(z.number())),
+	timezone: z.optional(z.string()),
+});
+export type ApiAccountPatch = z.infer<typeof apiAccountPatchSchema>;
+
+export const apiSubscriptionSchema = z.object({
+	type: z.literal("push"),
+	sessionId: z.number(),
+	push: z.object({
+		endpoint: z.optional(z.string()),
+		expirationTime: z.nullish(z.number()),
+		keys: z.record(z.string(), z.string()),
+	}),
+});
+export type ApiSubscription = z.infer<typeof apiSubscriptionSchema>;
+
+export interface ApiSession {
+	id: Id,
+	account?: ApiAccount,
+	push: boolean,
+}
+
+export const apiScheduleLocationSchema = defineEntity({
+	name: z.string(),
+	description: z.optional(z.string()),
+});
+export type ApiScheduleLocation = z.infer<typeof apiScheduleLocationSchema>;
+
+export const apiScheduleEventSlotSchema = z.object({
+	id: idSchema,
+	start: z.string(),
+	end: z.string(),
+	locationIds: z.array(idSchema),
+	assigned: z.optional(z.array(z.number())),
+	interested: z.optional(z.number()),
+});
+export type ApiScheduleEventSlot = z.infer<typeof apiScheduleEventSlotSchema>;
+
+export const apiScheduleEventSchema = defineEntity({
+	name: z.string(),
+	crew: z.optional(z.boolean()),
+	host: z.optional(z.string()),
+	cancelled: z.optional(z.boolean()),
+	description: z.optional(z.string()),
+	interested: z.optional(z.number()),
+	slots: z.array(apiScheduleEventSlotSchema),
+});
+export type ApiScheduleEvent = z.infer<typeof apiScheduleEventSchema>;
+
+export const apiScheduleRoleSchema = defineEntity({
+	name: z.string(),
+	description: z.optional(z.string()),
+});
+export type ApiScheduleRole = z.infer<typeof apiScheduleRoleSchema>;
+
+export const apiScheduleShiftSlotSchema = z.object({
+	id: idSchema,
+	start: z.string(),
+	end: z.string(),
+	assigned: z.optional(z.array(z.number())),
+});
+export type ApiScheduleShiftSlot = z.infer<typeof apiScheduleShiftSlotSchema>;
+
+export const apiScheduleShiftSchema = defineEntity({
+	roleId: idSchema,
+	name: z.string(),
+	description: z.optional(z.string()),
+	slots: z.array(apiScheduleShiftSlotSchema),
+});
+export type ApiScheduleShift = z.infer<typeof apiScheduleShiftSchema>;
+
+export const apiScheduleSchema = defineEntity({
+	id: z.literal(111),
+	locations: z.optional(z.array(apiScheduleLocationSchema)),
+	events: z.optional(z.array(apiScheduleEventSchema)),
+	roles: z.optional(z.array(apiScheduleRoleSchema)),
+	shifts: z.optional(z.array(apiScheduleShiftSchema)),
+});
+export type ApiSchedule = z.infer<typeof apiScheduleSchema>;
+
+export interface ApiAccountUpdate {
+	type: "account-update",
+	data: ApiAccount,
+}
+
+export interface ApiScheduleUpdate {
+	type: "schedule-update",
+	updatedFrom?: string,
+	data: ApiSchedule,
+}
+
+export type ApiEvent =
+	| ApiAccountUpdate
+	| ApiScheduleUpdate
+;
diff --git a/shared/types/common.ts b/shared/types/common.ts
new file mode 100644
index 0000000..061e713
--- /dev/null
+++ b/shared/types/common.ts
@@ -0,0 +1,25 @@
+import { z } from "zod/v4-mini";
+
+export const idSchema = z.number();
+export type Id = z.infer<typeof idSchema>;
+
+export const entityLivingSchema = z.object({
+	id: idSchema,
+	updatedAt: z.string(),
+	deleted: z.optional(z.literal(false)),
+});
+export type EnityLiving = z.infer<typeof entityLivingSchema>;
+
+export const entityToombstoneSchema = z.object({
+	id: idSchema,
+	updatedAt: z.string(),
+	deleted: z.literal(true),
+});
+export type EntityToombstone = z.infer<typeof entityToombstoneSchema>;
+
+export const entitySchema = z.discriminatedUnion("deleted", [entityLivingSchema, entityToombstoneSchema]);
+export type Entity = z.infer<typeof entitySchema>;
+
+export function defineEntity<T extends {}>(fields: T) {
+	return z.discriminatedUnion("deleted", [z.extend(entityLivingSchema, fields), entityToombstoneSchema]);
+}
diff --git a/shared/types/schedule.d.ts b/shared/types/schedule.d.ts
deleted file mode 100644
index cdad137..0000000
--- a/shared/types/schedule.d.ts
+++ /dev/null
@@ -1,65 +0,0 @@
-export interface ScheduleEvent {
-	name: string,
-	id: string,
-	crew?: boolean,
-	host?: string,
-	cancelled?: boolean,
-	description?: string,
-	interested?: number,
-	slots: TimeSlot[],
-}
-
-export interface ScheduleLocation {
-	name: string,
-	id: string,
-	description?: string,
-}
-
-export interface TimeSlot {
-	id: string,
-	start: string,
-	end: string,
-	locations: string[],
-	assigned?: number[],
-	interested?: number,
-}
-
-export interface Shift {
-	name: string,
-	id: string,
-	role: string,
-	description?: string,
-	slots: ShiftSlot[],
-}
-
-export interface Role {
-	name: string,
-	id: string,
-	description?: string,
-}
-
-export interface ShiftSlot {
-	id: string,
-	start: string,
-	end: string,
-	assigned?: number[],
-}
-
-export interface Schedule {
-	locations: ScheduleLocation[],
-	events: ScheduleEvent[],
-	roles?: Role[],
-	rota?: Shift[],
-}
-
-export type ChangeRecord<T extends { id: string }> =
-	| { op: "set", data: T }
-	| { op: "del", data: { id: string }}
-;
-
-export interface SchedulePatch {
-	locations?: ChangeRecord<ScheduleLocation>[],
-	events?: ChangeRecord<ScheduleEvent>[],
-	roles?: ChangeRecord<Role>[],
-	rota?: ChangeRecord<Shift>[],
-}
diff --git a/shared/utils/changes.ts b/shared/utils/changes.ts
deleted file mode 100644
index facb2d7..0000000
--- a/shared/utils/changes.ts
+++ /dev/null
@@ -1,21 +0,0 @@
-import type { ChangeRecord } from "~/shared/types/schedule";
-
-export function applyChange<T extends { id: string }>(change: ChangeRecord<T>, data: T[]) {
-	const index = data.findIndex(item => item.id === change.data.id);
-	if (change.op === "del") {
-		if (index !== -1)
-			data.splice(index, 1);
-	} else if (change.op === "set") {
-		if (index !== -1)
-			data.splice(index, 1, change.data);
-		else
-			data.push(change.data)
-	}
-}
-
-export function applyChangeArray<T extends { id: string }>(changes: ChangeRecord<T>[], data: T[]) {
-	// Note: quadratic complexity due to findIndex in applyChange
-	for (const change of changes) {
-		applyChange(change, data);
-	}
-}
diff --git a/shared/utils/functions.ts b/shared/utils/functions.ts
index b11db7d..22cf208 100644
--- a/shared/utils/functions.ts
+++ b/shared/utils/functions.ts
@@ -6,6 +6,15 @@ export function* enumerate<T>(iterable: Iterable<T>) {
 	}
 }
 
+/** Filters an iterable based on the passed predicate function */
+export function* filter<T, S extends T>(it: Iterable<T>, predicate: (value: T) => value is S) {
+	for (const value of it) {
+		if (predicate(value)) {
+			yield value;
+		}
+	}
+}
+
 /** Converts a name to an id */
 export function toId(name: string) {
 	return name.toLowerCase().replace(/[^a-z0-9]+/g, "-");
diff --git a/shared/utils/update.ts b/shared/utils/update.ts
new file mode 100644
index 0000000..9a8a040
--- /dev/null
+++ b/shared/utils/update.ts
@@ -0,0 +1,14 @@
+import type { Entity } from "~/shared/types/common";
+
+export function applyUpdatesToArray<T extends Entity>(updates: T[], entities: T[]) {
+	const idMap = new Map(entities.map((e, i) => [e.id, i]));
+	for (const update of updates) {
+		const index = idMap.get(update.id);
+		if (index !== undefined) {
+			entities[index] = update;
+		} else {
+			idMap.set(update.id, entities.length);
+			entities.push(update);
+		}
+	}
+}
diff --git a/stores/account.ts b/stores/account.ts
index 624ce8f..e1f4c03 100644
--- a/stores/account.ts
+++ b/stores/account.ts
@@ -1,4 +1,4 @@
-import type { Account } from "~/shared/types/account";
+import type { ApiAccount, ApiAccountPatch } from "~/shared/types/api";
 
 export const useAccountStore = defineStore("account", () => {
 	const runtimeConfig = useRuntimeConfig();
@@ -8,8 +8,9 @@ export const useAccountStore = defineStore("account", () => {
 		id: ref<number>(),
 		name: ref<string>(),
 		timezone: ref<string>(),
-		type: ref<Account["type"]>(),
-		interestedIds: ref<Set<string>>(new Set()),
+		type: ref<ApiAccount["type"]>(),
+		interestedEventIds: ref<Set<number>>(new Set()),
+		interestedEventSlotIds: ref<Set<number>>(new Set()),
 	};
 
 	watchEffect(() => {
@@ -19,7 +20,8 @@ export const useAccountStore = defineStore("account", () => {
 		state.name.value = account?.name;
 		state.timezone.value = account?.timezone;
 		state.type.value = account?.type;
-		state.interestedIds.value = new Set(account?.interestedIds ?? []);
+		state.interestedEventIds.value = new Set(account?.interestedEventIds ?? []);
+		state.interestedEventSlotIds.value = new Set(account?.interestedEventSlotIds ?? []);
 	});
 
 	const getters = {
@@ -31,23 +33,34 @@ export const useAccountStore = defineStore("account", () => {
 	};
 
 	const actions = {
-		async toggleInterestedId(id: string, slotIds?: string[]) {
-			if (!state.interestedIds.value) {
-				throw Error("accountStore.toggleInterestedId: Invalid state")
-			}
-			let newIds = [...state.interestedIds.value ?? []];
-			if (state.interestedIds.value.has(id)) {
-				newIds = newIds.filter(newId => newId !== id);
-			} else {
-				newIds.push(id);
-				if (slotIds) {
-					const filterIds = new Set(slotIds);
-					newIds = newIds.filter(newId => !filterIds.has(newId));
+		async toggleInterestedId(type: "event" | "slot", id: number, slotIds?: number[]) {
+			let newEventIds = new Set(state.interestedEventIds.value);
+			let newSlotIds = new Set(state.interestedEventSlotIds.value);
+			if (type === "event") {
+				if (newEventIds.has(id)) {
+					newEventIds.delete(id)
+				} else {
+					newEventIds.add(id);
+					if (slotIds) {
+						for (const slotId of slotIds) {
+							newSlotIds.delete(slotId)
+						}
+					}
 				}
+			} else if (type === "slot") {
+				if (newSlotIds.has(id)) {
+					newSlotIds.delete(id);
+				} else {
+					newSlotIds.add(id);
+				}
+			}
+			const patch: ApiAccountPatch = {
+				interestedEventIds: [...newEventIds],
+				interestedEventSlotIds: [...newSlotIds],
 			}
 			await $fetch("/api/auth/account", {
 				method: "PATCH",
-				body: { interestedIds: newIds },
+				body: patch,
 			})
 			await sessionStore.fetch();
 		},
diff --git a/stores/schedules.ts b/stores/schedules.ts
index f7d8ab1..a29cd2d 100644
--- a/stores/schedules.ts
+++ b/stores/schedules.ts
@@ -1,8 +1,9 @@
-import type { Schedule } from "~/shared/types/schedule";
+import type { ApiSchedule } from "~/shared/types/api";
+import { applyUpdatesToArray } from "~/shared/utils/update";
 
 interface SyncOperation {
 	controller: AbortController,
-	promise: Promise<Ref<Schedule>>,
+	promise: Promise<Ref<ApiSchedule>>,
 }
 
 export const useSchedulesStore = defineStore("schedules", () => {
@@ -10,7 +11,7 @@ export const useSchedulesStore = defineStore("schedules", () => {
 
 	const state = {
 		activeScheduleId: ref<number | undefined>(111),
-		schedules: ref<Map<number, Ref<Schedule>>>(new Map()),
+		schedules: ref<Map<number, Ref<ApiSchedule>>>(new Map()),
 		pendingSyncs: ref<Map<number, SyncOperation>>(new Map()),
 	};
 
@@ -82,9 +83,25 @@ export const useSchedulesStore = defineStore("schedules", () => {
 	})
 
 	appEventSource?.addEventListener("update", (event) => {
+		if (event.data.type !== "schedule-update") {
+			return;
+		}
 		const schedule = state.schedules.value.get(111);
-		if (schedule) {
-			schedule.value = event.data;
+		const update = event.data.data;
+		// XXX validate updatedFrom/updatedAt here
+		if (schedule && !schedule.value.deleted && !update.deleted) {
+			if (update.locations) {
+				applyUpdatesToArray(update.locations, schedule.value.locations = schedule.value.locations ?? []);
+			}
+			if (update.events) {
+				applyUpdatesToArray(update.events, schedule.value.events = schedule.value.events ?? []);
+			}
+			if (update.roles) {
+				applyUpdatesToArray(update.roles, schedule.value.roles = schedule.value.roles ?? []);
+			}
+			if (update.shifts) {
+				applyUpdatesToArray(update.shifts, schedule.value.shifts = schedule.value.shifts ?? []);
+			}
 		}
 	});
 
diff --git a/stores/session.ts b/stores/session.ts
index cb01564..7b91538 100644
--- a/stores/session.ts
+++ b/stores/session.ts
@@ -1,6 +1,6 @@
 import { appendResponseHeader } from "h3";
 import type { H3Event } from "h3";
-import type { Account } from "~/shared/types/account";
+import type { ApiAccount } from "~/shared/types/api";
 
 const fetchSessionWithCookie = async (event?: H3Event) => {
 	// Client side
@@ -21,7 +21,7 @@ const fetchSessionWithCookie = async (event?: H3Event) => {
 
 export const useSessionStore = defineStore("session", () => {
 	const state = {
-		account: ref<Account>(),
+		account: ref<ApiAccount>(),
 		id: ref<number>(),
 		push: ref<boolean>(false),
 	};
diff --git a/utils/functions.ts b/utils/functions.ts
index 1b69c0d..2fdafd8 100644
--- a/utils/functions.ts
+++ b/utils/functions.ts
@@ -7,3 +7,11 @@ export function queryToString(item?: null | LocationQueryValue | LocationQueryVa
 		return queryToString(item[0])
 	return item;
 }
+
+export function queryToNumber(item?: null | LocationQueryValue | LocationQueryValue[]) {
+	if (item === null || item === undefined)
+		return undefined;
+	if (item instanceof Array)
+		return queryToNumber(item[0])
+	return Number.parseInt(item, 10);
+}