What is CI/CD pipelines?

CI/CD transforms software deployment from a terrifying, manual, once-a-quarter event into an automated, multiple-times-per-day routine. Continuous Integration (CI) triggers automatically when a developer pushes code: the pipeline clones the repository, installs dependencies, compiles the code, runs the full test suite (unit tests, integration tests, end-to-end tests), checks code quality (linting, type checking), and reports results within minutes. If any check fails, the merge is blocked. Continuous Deployment (CD) extends this: when all CI checks pass on the main branch, the pipeline automatically builds a production artifact, deploys it to staging for smoke tests, and promotes it to production with zero-downtime rolling updates. Modern CI/CD pipelines on platforms like GitHub Actions or Vercel handle the entire lifecycle in under 3 minutes. Advanced implementations include: preview deployments (every pull request gets its own URL for visual review), canary releases (deploying to 5% of traffic first and monitoring error rates before full rollout), and automatic rollback (reverting to the previous deployment if error rates spike). For AI-native applications, CI/CD also includes prompt regression testing and embedding model validation.