# Scheduled Tasks (Cron)

Recurring tasks using cron. For one-off future runs, use the **delay** option.

## Define a Scheduled Task

```ts
import { schedules } from "@trigger.dev/sdk";

export const task = schedules.task({
  id: "first-scheduled-task",
  run: async (payload) => {
    payload.timestamp; // Date (scheduled time, UTC)
    payload.lastTimestamp; // Date | undefined
    payload.timezone; // IANA, e.g. "America/New_York" (default "UTC")
    payload.scheduleId; // string
    payload.externalId; // string | undefined
    payload.upcoming; // Date[]

    payload.timestamp.toLocaleString("en-US", { timeZone: payload.timezone });
  },
});
```

> Scheduled tasks need at least one schedule attached to run.

## Attach Schedules

**Declarative (sync on dev/deploy):**

```ts
schedules.task({
  id: "every-2h",
  cron: "0 */2 * * *", // UTC
  run: async () => {},
});

schedules.task({
  id: "tokyo-5am",
  cron: { pattern: "0 5 * * *", timezone: "Asia/Tokyo", environments: ["PRODUCTION", "STAGING"] },
  run: async () => {},
});
```

**Imperative (SDK or dashboard):**

```ts
await schedules.create({
  task: task.id,
  cron: "0 0 * * *",
  timezone: "America/New_York", // DST-aware
  externalId: "user_123",
  deduplicationKey: "user_123-daily", // updates if reused
});
```

### Dynamic / Multi-tenant Example

```ts
// /trigger/reminder.ts
export const reminderTask = schedules.task({
  id: "todo-reminder",
  run: async (p) => {
    if (!p.externalId) throw new Error("externalId is required");
    const user = await db.getUser(p.externalId);
    await sendReminderEmail(user);
  },
});
```

```ts
// app/reminders/route.ts
export async function POST(req: Request) {
  const data = await req.json();
  return Response.json(
    await schedules.create({
      task: reminderTask.id,
      cron: "0 8 * * *",
      timezone: data.timezone,
      externalId: data.userId,
      deduplicationKey: `${data.userId}-reminder`,
    })
  );
}
```

## Cron Syntax (no seconds)

```
* * * * *
| | | | └ day of week (0–7 or 1L–7L; 0/7=Sun; L=last)
| | | └── month (1–12)
| | └──── day of month (1–31 or L)
| └────── hour (0–23)
└──────── minute (0–59)
```

## When Schedules Won't Trigger

- **Dev:** only when the dev CLI is running.
- **Staging/Production:** only for tasks in the **latest deployment**.

## SDK Management

```ts
await schedules.retrieve(id);
await schedules.list();
await schedules.update(id, { cron: "0 0 1 * *", externalId: "ext", deduplicationKey: "key" });
await schedules.deactivate(id);
await schedules.activate(id);
await schedules.del(id);
await schedules.timezones(); // list of IANA timezones
```
