GitHub Actions vs GitLab CI vs Jenkins: Key Lessons for Reliable CI/CD Pipelines

A software developer compared three major CI/CD platforms—GitHub Actions, GitLab CI, and Jenkins—after struggling with slow, unreliable build pipelines. The core insight was that effective pipelines depend less on the tool chosen and more on applying consistent principles across any platform. The developer identified four key rules: start every build from a clean slate, restore dependencies deterministically, run tests in parallel, and publish artifacts only after all checks pass. Practical improvements included using npm ci instead of npm install, caching dependencies based on lockfile hashes, and uploading build artifacts only on success. Applying these patterns to all three platforms significantly reduced build times and improved pipeline reliability.