CI/CD (Continuous Integration & Continuous Deployment)

What is CI/CD?

CI/CD is a software development practice that automates the process of testing, integrating, and deploying code. Instead of manually running tests and deploying updates, CI/CD pipelines do it automatically whenever code changes.

Continuous Integration (CI): Automatically test code every time developers push changes. Catch bugs early before they reach production.

Continuous Deployment (CD): Automatically deploy passing code to production. Ship features and fixes faster.

The Problem CI/CD Solves

Without CI/CD: Developers push code, someone manually runs tests, if tests pass, someone manually deploys to servers. This takes hours or days, and human error causes bugs.

With CI/CD: Push code → Tests run automatically → If tests pass, deploy automatically. This takes minutes, and automation eliminates human error.

How It Works

1. Developer pushes code to GitHub
2. CI server (Jenkins, GitHub Actions) detects the change
3. Runs automated tests (unit tests, integration tests)
4. If tests pass, builds the application
5. Deploys to staging or production automatically

All of this happens in minutes without manual intervention.

Real-World Impact

Netflix deploys thousands of times per day using CI/CD. When a bug is found, they fix and deploy within minutes.

Amazon deploys code every 11.6 seconds on average. CI/CD enables this velocity while maintaining quality.