Prerequisites

Before we start, make sure you have:

• A Vercel account.
• A Next.js project ready to deploy.
• Familiarity with cron expressions.

Video Tutorial

Step 1: Create a New Next.js App

First, if you haven't already created a Next.js app, use the following command to create one:

npx create-next-app next-cronjob

Step 2: Create the Cron Job API Route

Create a serverless API route that will be triggered by Vercel's cron job scheduler to execute the desired functionality.

// app/api/cron/route.ts
import { type NextRequest, NextResponse } from 'next/server'
		
export async function GET(
  req: NextRequest
) {
  return new NextResponse.json(
    { message: 'Cron job executed successfully' }),
    { status: 200 }
  );
}

Step 3: Configure the Cron Job in vercel.json

In the vercel.json file, add your cron job configuration:

// vercel.json
{
  "crons": [
    {
      "path": "/api/cron",
      "schedule": "0 5 * * *"
    }
  ]
}

This will run the cron job every day at 5:00 AM UTC.

Step 4 (Optional): Secure Your Cron Job

Add a CRON_SECRET environment variable to your Vercel project for extra security. Use this command to generate a secret:

node -e "console.log(require('crypto').randomBytes(32).toString('hex'))"

Command Output:

c2b61cc7507a0b46dc893455e1647276be63782bab0270556c32e928906f4e68

Then, update your API route:

// app/api/cron/route.ts
import { type NextRequest, NextResponse } from 'next/server'
		
export async function GET(
  req: NextRequest
) {
  // If token is valid, proceed with the API logic
  const authToken = req.headers.get('authorization')?.replace('Bearer ', '');
    
  if (authToken !== process.env.CRON_SECRET) {
    return NextResponse.json(
      { error: 'Unauthorized access. Invalid token.' },
      { status: 401 }
    );
  }
		
  return new NextResponse.json(
    { message: 'Secure API accessed successfully' }),
    { status: 200 }
  );
}

Step 5: Deploy to Vercel

Deploy your app by connecting your Git repository to Vercel or using the Vercel CLI:

vercel deploy --prod

Once deployed, your cron job will be scheduled automatically.

Step 6: Monitor Cron Jobs

In the Vercel dashboard:

• Go to Settings > Cron Jobs.
• You can view, run manually, and check logs for cron jobs.

Cron Job Usage & Limits on Plans

Cron jobs are available on all Vercel plans and invoke Serverless or Edge Functions, adhering to the same usage and pricing limits.

Plan Limits:

Each project has a hard limit of 20 cron jobs.

Conclusion

With Vercel's cron jobs, you can easily automate tasks like data syncing or email sending in your Next.js app. Simply set up an API route, configure it in vercel.json, and deploy. You can also secure and monitor your cron jobs directly from the Vercel dashboard.