What Is and How To Use Cron Jobs With GitHub

If you’ve ever needed to run a script automatically on a schedule — like every day at midnight or every hour — you’re looking for a cron job.

But did you know you can run cron jobs directly on GitHub, without any servers or infrastructure?

Here’s a simple, modern developer’s guide to cron jobs using GitHub Actions.

What Is a Cron Job?

A cron job is just a time-based task scheduler. It tells your system:

“Run this script at X time, every Y interval.”

Traditionally, you’d configure this on a Linux server using the crontab command. But in 2025, we can do better: serverless automation right inside GitHub.

Quick Guide to Cron Syntax in GitHub

When you define:

schedule:
  - cron: '0 0 * * *'

You’re telling GitHub Actions:

“Run this job at 00:00 UTC every day.”

Cron expressions follow this format:

┌───────────── minute (0 - 59)
│ ┌───────────── hour (0 - 23)
│ │ ┌───────────── day of month (1 - 31)
│ │ │ ┌───────────── month (1 - 12)
│ │ │ │ ┌───────────── day of week (0 - 6) (Sunday = 0)
│ │ │ │ │
│ │ │ │ │
* * * * *

Useful Examples

Why Use Cron Jobs With GitHub?

You get:

• Free compute (via GitHub Actions)

• No infrastructure to manage

• Native access to your repos, issues, APIs, etc.

• Logs, versioning, and PR-triggered logic

Perfect for:

• Running cleanup scripts

• Syncing data with APIs

• Sending reports or summaries

• Keeping dependencies updated

Real Use Case Examples

• Fetch and store latest API data daily

• Close stale GitHub issues every week

• Ping an endpoint to keep a server warm

• Post a Slack message every Monday

You can even integrate secrets, fetch remote content, and trigger workflows conditionally.

How To Set Up a GitHub Cron Job (Step-by-Step)

1. Create a .github/workflows/cron.yml file in your repo:

name: Run Scheduled Job

on:
  schedule:
    - cron: '0 0 * * *' # every day at midnight UTC
  workflow_dispatch: # optional: lets you trigger it manually

jobs:
  run-script:
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v4
      - name: Run My Script
        run: node ./scripts/my-script.js

🧠 Tip: Use crontab.guru to craft your cron expression.

2. Commit and push. GitHub will now run that job automatically on your schedule.

⚠️ GitHub Cron Jobs Are Not Precisely Timed

Here’s something many developers miss: GitHub Actions doesn’t guarantee exact execution time for scheduled workflows.

When you schedule a job for 0 0 * * * (midnight UTC), GitHub might not run it exactly at midnight. Instead, you could see a delay of several minutes, sometimes even longer, depending on how many scheduled jobs GitHub is processing at that time.

This happens because:

• GitHub queues thousands of cron-based workflows across all public and private repos.

• There’s no SLA (service-level agreement) for precise timing.

Workarounds & Alternatives

Use GitHub Enterprise / Premium Runners

With GitHub-hosted runners on a paid plan, especially self-hosted or enterprise-level runners, you may see:

• Reduced queue times

• More predictable scheduling

• Higher concurrency limits

But still, even GitHub Enterprise doesn’t promise second-level accuracy.

Use External Scheduling Services

If timing is critical (e.g., you must hit an API exactly at 03:00 UTC), consider using:

• cron-job.org — Free, simple cron-as-a-service

• AWS EventBridge Scheduler — Cloud-native, scalable, precise

• Zapier / n8n / Make — Great for no-code API automation

• Cloudflare Workers + Cron Triggers — Fast, serverless, highly reliable

These services hit your endpoint or trigger a GitHub workflow_dispatch event, giving you tighter control.

For real-time-sensitive or coordinated operations, consider external schedulers or a hybrid model (e.g., external trigger → GitHub Action via API).

Debugging + Best Practices

• Always add workflow_dispatch so you can test manually

• Use actions/setup-node if your script needs Node/npm

• Use GitHub cron jobs when timing isn’t critical, like:

  • Daily cleanup tasks

  • Weekly reports

  • API syncs with buffer room

Final Thoughts

GitHub Actions + cron is cron-as-a-service---a powerful, free tool for automation that lives next to your code. You don’t need to spin up servers or deploy functions. Just commit and let it run. Until next time!