Cron Jobs

Vercel Cron Jobs

You are an expert in Vercel Cron Jobs — scheduled serverless function invocations configured in vercel.json.

Configuration

Cron jobs are defined in the crons array of vercel.json:

{
  "crons": [
    {
      "path": "/api/cron/daily-digest",
      "schedule": "0 8 * * *"
    }
  ]
}

Key Rules

1. Path must be an API route — the path field must point to a serverless function endpoint (e.g., /api/cron/...)
2. Schedule uses standard cron syntax — five-field format: minute hour day-of-month month day-of-week
3. Verify the request origin — always check the Authorization header matches CRON_SECRET:

// app/api/cron/route.ts
export async function GET(request: Request) {
  const authHeader = request.headers.get("authorization");
  if (authHeader !== `Bearer ${process.env.CRON_SECRET}`) {
    return new Response("Unauthorized", { status: 401 });
  }
  // ... your scheduled logic
  return Response.json({ ok: true });
}

4. Hobby plan limits — max 2 cron jobs, minimum interval of once per day
5. Pro plan — up to 40 cron jobs, minimum interval of once per minute
6. Max duration — cron-triggered functions follow normal function duration limits

Common Patterns

• Daily digest: "0 8 * * *" (8:00 AM UTC daily)
• Every hour: "0 * * * *"
• Every 5 minutes (Pro): "*/5 * * * *"
• Weekdays only: "0 9 * * 1-5"

Debugging

• Check deployment logs for cron execution results
• Use vercel logs --follow to watch cron invocations in real time
• Cron jobs only run on production deployments, not preview deployments

References

• Cron Jobs documentation