Cron Jobs Agent Skill

---
description: Scheduled tasks with Vercel Cron, Inngest, node-cron, crontab syntax, and error handling.
homepage: https://yepapi.com/skills/cron-jobs
metadata:
  tags: [cron, scheduling, jobs, automation]
---

# Cron Jobs

## Rules

- Vercel Cron: define in `vercel.json` with `{ "crons": [{ "path": "/api/cron/task", "schedule": "0 * * * *" }] }`
- Secure cron endpoints: verify `Authorization: Bearer ${CRON_SECRET}` header — prevent unauthorized invocations
- Idempotent handlers — cron jobs can fire twice; always check if work was already done
- Timeout awareness: Vercel functions timeout at 10s (hobby) / 60s (pro) — offload long tasks to queues
- Inngest for complex scheduling: `inngest.createFunction({ id: "...", cron: "0 9 * * *" }, handler)`
- node-cron for self-hosted: `cron.schedule("*/5 * * * *", task)` — only for persistent servers
- Crontab syntax: `minute hour day month weekday` — use https://crontab.guru to verify
- Log every run with start time, end time, success/failure, items processed
- Error handling: wrap in try/catch, report failures to logging/alerting, don't let one failure stop the next run

## Patterns

```json
// vercel.json
{
  "crons": [
    { "path": "/api/cron/daily-report", "schedule": "0 9 * * *" },
    { "path": "/api/cron/cleanup", "schedule": "0 0 * * 0" }
  ]
}
```

```ts
// Cron route handler
export async function GET(req: Request) {
  const authHeader = req.headers.get("authorization");
  if (authHeader !== `Bearer ${process.env.CRON_SECRET}`) {
    return new Response("Unauthorized", { status: 401 });
  }

  try {
    const result = await runScheduledTask();
    return Response.json({ success: true, processed: result.count });
  } catch (error) {
    console.error("Cron job failed:", error);
    return Response.json({ success: false, error: String(error) }, { status: 500 });
  }
}
```

## Common Schedules

| Schedule | Cron | Description |
|----------|------|-------------|
| Every hour | `0 * * * *` | Top of each hour |
| Daily 9am UTC | `0 9 * * *` | Morning reports |
| Weekly Sunday | `0 0 * * 0` | Cleanup tasks |
| Every 5 min | `*/5 * * * *` | Polling/sync |

## Avoid

- Exposing cron endpoints without auth — anyone could trigger them
- Long-running work inside the handler — offload to a queue for tasks > 10s
- Assuming exact timing — cron jobs can be delayed; design for idempotency
- Forgetting error handling — one uncaught error should not break the schedule