In the modern web, we've been trained to think that even a simple cron job requires a server. Whether it's a Lambda function, a Heroku dyno, or a DigitalOcean droplet, the costs (and maintenance) add up.

But for many Micro-SaaS products, GitHub Actions can serve as the entire backend infrastructure for $0/month.

The "Action-First" Architecture

The core idea is simple: GitHub repository events and scheduled triggers are effectively serverless entry points.

1. The Scheduled Worker (The Cron Replacement)

If your app depends on data that changes once an hour—like pricing, weather, or news—you don't need a running server.

• Setup: A .github/workflows/fetch-data.yml runs every hour.
• Action: It fetches data from an API, parses it, and commits it back to a data.json file in your repo.
• Frontend: Your Next.js app fetches the static data.json on the client or during build time. This is "Static Data Injection" at its finest.

2. The API Trigger (The Webhook Replacement)

GitHub allows you to trigger a workflow via a simple POST request (the repository_dispatch event).

• Setup: A user interacts with your UI.
• Action: Your frontend sends a request to the GitHub API. GitHub spins up a runner, executes your business logic (e.g., generating a PDF, processing an image), and stores the result.
• Result: You've just performed "serverless compute" without a dedicated cloud provider.

Case Study: The "0-Cost" News Aggregator

I once built a small news aggregator that tracked obscure tech blogs.

• Input: A list of RSS feeds.
• Logic: A GH Action ran every 6 hours, scraped new entries, and used a small script to summarize them using an LLM API.
• Output: It pushed a new .md file to a posts/ folder and triggered a Vercel rebuild.
• Cost: $0. Total maintenance: 0 hours per month.

When NOT to use this

GitHub Actions is powerful, but it's not a real-time API. Latency for a cold-start runner can be 10-30 seconds. If your user is waiting for a response in their browser, this is the wrong tool. But if your task is asynchronous (e.g., "We'll email you when your report is ready"), it's perfect.

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In our next tutorial, we'll dive into how to secure these workflows so you don't accidentally leak your business secrets.