Next.js Cron Guide

This guide covers deploying an API endpoint to Vercel and triggering it once every hour using Slater.

Create an API endpoint

To create a new endpoint in Next.js, simply add a file to the /api folder.

If you don't have an existing Next.js app, use npx create-next-app to get started quickly.

Here's an example:

// /api/crons/expire.js
export default function handler(req, res) {
  try {
    // delete this for your business logic instead
    const result = db.updateMany({
      where: { date: { lte: new Date().toISOString() } },
      data: { expired: true },
    });
 
    return status(200).json({
      data: result.map((x) => x.id),
      message: `expired ${result.length} records`,
    });
  } catch (err) {
    res.status(500).json({ error: "internal error", message: err });
    console.log(err);
  }
}

Deployment

Add environment variables

Come up with what your process.env.SLATER_SECRET will be and set it as an environment variable in Vercel. After setting the value, you might need to trigger a redeployment so the latest value is live.

Read more

Deploy to Vercel

To deploy your application to Vercel, you can either:

1. Connect your GitHub repository (recommended)
2. Use the CLI to manually push up and deploy the application

For path number one, simply click "new project" in the Vercel dashboard and select your existing GitHub repository.

For path number two, install the Vercel CLI in your terminal and run vercel --prod.

Set up Slater

After deploying to Vercel, you'll have a production domain. Test the endpoint is working by manually visiting https://YOUR_SUBDOMAIN.vercel.app/api/crons/expire. With the above example code, if you get back a result of {data: [1,2,3], message: 'expired 3 records'} then you're good to go.

Next, create an application in Slater.

Free tier

For a limited time, all new Slater accounts come with 2,000 executions for free. This means no credit card is required to get started. Once you run out of executions, you'll get an email asking you to buy more.

Sign in with Github to claim your 2,000 free executions.

Determining your cron schedule

Using crontab.guru, figure out the cron expression that relates to the interval you want to trigger your function at.

Confirming it's working

Slater schedules it's tasks five minutes prior to executing them, so check back prior to your cron executing. We're working to add manual triggers as well in an upcoming release.

Gray jobs are scheduled but yet to be run, red jobs have errored in some way, and green jobs were processed successfully.