As your organization grows, so does your GitHub bill. CI/CD developers often treat compute as infinite, but at scale, every unnecessary second of execution time translates into thousands of dollars of wasted revenue.

Here is how we tune GitHub Actions for maximum performance at GitTech.

1. The Power of Selective Execution

The fastest Action is the one that doesn't run.

• The Filter: Use on: push: paths: to ensure that backend tests only run when backend code changes.
• The Result: You eliminate 40-60% of unnecessary build runs, drastically reducing your concurrency bottlenecks.

2. Master the Matrix

If you need to test against 10 different Node.js versions or 5 different operating systems, don't run them sequentially.

• The Strategy: Use the strategy: matrix: property. GitHub will spin up parallel runners for every combination.
• The Result: A build that would take 50 minutes sequentially now takes 5 minutes in parallel.

3. Advanced Caching Strategies

GitHub's standard actions/cache is good, but for high-scale apps, you need more.

• Layered Docker Caching: Use the type=gha cache backend for Docker builds. This ensures that even heavy container builds can reuse previous layers directly from the GitHub Action cache.
• Dependency Locking: Always use lockfiles (package-lock.json, bun.lock) to ensure that your "Install" steps are deterministic and can be cached effectively.

4. Resource Allocation

Don't use a sledgehammer to crack a nut.

• The Runner Choice: Large runners (with more CPU/RAM) are available for enterprise accounts. For heavy compilation tasks (like Rust or C++ builds), these pay for themselves by reducing execution time.
• The Cleanup: Ensure your workflows include cleanup steps to remove temporary artifacts and free up runner disk space, preventing "Disk Full" errors in long-running jobs.

Performance is a feature. In our next post, we'll see how to use these high-speed workflows to keep your customers happy.