CI vs CD (Continuous Integration vs Continuous Deployment) — What's the Difference?

Continuous Integration (CI) automatically builds and tests every code change when it is merged; Continuous Delivery or Deployment (CD) automatically releases the tested build, to a staging environment or all the way to production.

The concept

CI catches integration bugs early by running tests on each push. CD removes manual deployment steps so releases are small, frequent and low-risk.

Continuous delivery keeps a manual approval before production; continuous deployment ships every passing change automatically.

Pipeline

Push code → CI builds the project
CI runs tests and linters
CD packages and deploys to staging
Approval (delivery) or auto-release (deployment) to production

Practical examples

GitHub Actions CI

name: CI
on: [push]
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: npm ci
      - run: npm test

Deploy on main

deploy:
  needs: test
  if: github.ref == 'refs/heads/main'
  runs-on: ubuntu-latest
  steps:
    - run: ./deploy.sh

Protect main

Require status checks to pass before merge

Common mistakes

CI that nobody fixes when red.
Slow pipelines that discourage commits.
Deploying without rollback.

Key takeaways

CI = build + test every change.
CD = automated release.
Delivery needs approval, deployment does not.

FAQ

Do I need both?

CI is the foundation; add CD as your tests become trustworthy.

Popular tools?

GitHub Actions, GitLab CI, Jenkins, CircleCI.