💡 Best Practices for GitHub Actions in JavaScript/TypeScript Monorepos

Working with monorepos can be awesome — but without the right CI/CD setup, things can quickly get slow, messy, and error-prone.

Here are a few lessons I’ve learned while building such a system using GitHub Actions.

🔹 1. Test CI/CD pipeline locally using Act CLI

Act CLI allows you to run GitHub Actions pipelines locally before pushing to GitHub. ACT repo: https://github.com/nektos/act

🔹 2. Only build what changes

Instead of rebuilding the whole monorepo on every push, configure workflows to detect which services/packages actually changed. This keeps pipelines fast and efficient.

🔹 3. Reuse workflows

Don’t duplicate logic across services. Use workflow_call and reusable templates so every service follows the same process while keeping configs DRY.

🔹 4. Leverage caching

Node.js projects can speed up builds significantly with dependency caching (actions/cache). A properly tuned cache saves minutes on every run.

🔹 5. Modular architecture

Organize your monorepo so services live in services/ and shared code in packages/. This separation encourages reuse and makes CI rules easier to manage.

The result? ✅ Faster deployments, fewer broken builds, and a developer experience that scales with your repo.

If you’re working with GitHub Actions and JS/TS monorepos, check out the repo

— would love feedback and ideas on how you approach CI/CD in your projects.

Here is the GitHub Actions repo: https://github.com/olivernaaris/tether-ci-cd/tree/main