diff --git a/typescript/types/sched.d.ts b/typescript/types/sched.d.ts
new file mode 100644
index 000000000..0b520c367
--- /dev/null
+++ b/typescript/types/sched.d.ts
@@ -0,0 +1,70 @@
+declare module Sched {
+  const enum Dow {
+    SUN = 1,
+    MON = 2,
+    TUE = 4,
+    WED = 8,
+    THU = 16,
+    FRI = 32,
+    SAT = 64,
+  }
+
+  type VibratePattern = "." | "," | "-" | ":" | ";" | "=";
+
+  type Sched = {
+    id?: string,
+    appid?: string,
+    on: boolean,
+    dow?: number,
+    date?: `${number}-${number}-${number}`,
+    msg: string,
+    last: number,
+    rp: boolean, // repeat
+    vibrate?: VibratePattern,
+    hidden?: boolean,
+    as?: boolean, // auto snooze
+    del?: boolean,
+    js?: string,
+    data?: unknown,
+  } & (
+    {
+      t: number, // time of day since midnight (in ms, set automatically when timer starts)
+    } | {
+      timer: number, // this is a timer - the time in ms
+    }
+  );
+
+  type SchedSettings = {
+    unlockAtBuzz: boolean,
+    defaultSnoozeMillis: number,
+    defaultAutoSnooze: boolean,
+    defaultDeleteExpiredTimers: boolean,
+    buzzCount: number,
+    buzzIntervalMillis: number,
+    defaultAlarmPattern: string,
+    defaultTimerPattern: string,
+  };
+
+  function getAlarms(): Sched[];
+
+  function setAlarms(alarms: readonly Sched[]): void;
+
+  function getAlarm(id: string): Sched | undefined;
+
+  function getActiveAlarms (alarms: Sched[], time?: Date): Sched[];
+
+  function setAlarm(id: string, alarm?: Sched): void;
+
+  function getTimeToAlarm(alarm: Sched, time?: Date): number | undefined;
+  function getTimeToAlarm(alarm?: undefined | null, time?: Date): undefined;
+
+  function reload(): void;
+
+  function newDefaultAlarm(): Sched;
+
+  function newDefaultTimer(): Sched;
+
+  function getSettings(): SchedSettings;
+
+  function setSettings(settings: SchedSettings): void;
+}