clocktower

Cron jobs for Next.js. Serverless-native.

Zero runtime dependencies. TypeScript-first. Works with Vercel Cron out of the box.

npm install croncall

// lib/jobs.ts
import { createClockTower } from "croncall";

export const tower = createClockTower({
  jobs: {
    syncUsers: {
      schedule: "0 * * * *", // every hour
      handler: async () => {
        await db.syncUsersFromExternalAPI();
      },
      description: "Sync users from external API",
      retry: { maxAttempts: 3, backoff: "exponential" },
      timeout: 30_000,
    },
    sendDigest: {
      schedule: "0 9 * * 1", // Mondays at 9 AM UTC
      handler: async () => {
        await email.sendWeeklyDigest();
      },
      description: "Send weekly digest email",
    },
    cleanupSessions: {
      schedule: "@daily",
      handler: async () => {
        await db.deleteExpiredSessions();
      },
    },
  },
  secret: process.env.CRON_SECRET,
});

// app/api/cron/route.ts
import { createCronHandler } from "croncall/next";
import { tower } from "@/lib/jobs";

export const GET = createCronHandler(tower);

Add cron schedules to vercel.json:

{
  "crons": [
    { "path": "/api/cron?job=syncUsers", "schedule": "0 * * * *" },
    { "path": "/api/cron?job=sendDigest", "schedule": "0 9 * * 1" },
    { "path": "/api/cron?job=cleanupSessions", "schedule": "0 0 * * *" }
  ]
}

Or generate it programmatically:

import { generateVercelCron } from "croncall/next";
import { tower } from "./lib/jobs";

console.log(JSON.stringify(generateVercelCron(tower, "/api/cron"), null, 2));

Each job has:

| Field | Type | Required | Description | |---------------|--------------------------------|----------|--------------------------------------| | schedule | string