GitHub Actions vs GitLab CI vs Jenkins: CI/CD Tools Compared

The short answer

All three tools do the core job: build the project, run tests and deploy on every change. The real difference is where your code lives and how much time you are willing to spend maintaining the CI system itself.

• GitHub Actions is built into GitHub, nothing to install. The best choice if your repositories are already there.
• GitLab CI is built into GitLab (cloud or self-hosted). Convenient when you want one tool for code, issues, container registry and CI.
• Jenkins is a standalone open-source server. Extremely flexible, works with any Git host, but needs constant care.

Side-by-side comparison

Hosting model

GitHub Actions and cloud GitLab CI are SaaS: the provider runs the CI service, you only write configuration. Both let you attach your own runners, for example when a build needs access to an internal network or powerful hardware.

Jenkins is always yours to run: controller, agents, updates, backups. That is a plus for companies with strict data residency rules and a minus for a small team without a DevOps engineer.

Self-hosted GitLab sits in the middle: the whole stack is on your server, but CI is already integrated and does not have to be assembled from plugins.

Configuration syntax

GitHub Actions and GitLab CI use YAML stored in the repository next to your code. A simple GitHub Actions pipeline:

name: CI
on: [push]
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: 20
      - run: npm ci
      - run: npm test

The GitLab CI equivalent:

test:
  image: node:20
  script:
    - npm ci
    - npm test

Jenkins pipelines live in a Jenkinsfile written in a Groovy DSL. It handles complex logic well, but the learning curve is steeper and errors often show up only at runtime.

Runners and pricing

Exact plans change, so focus on cost factors rather than numbers from blog posts:

• Hosted minutes. GitHub and GitLab include a free allowance, then bill for runner time. The rate depends on the OS and machine size.
• Self-hosted runners. You pay only for your own servers, which pays off at high build volume.
• Jenkins is free software, but you pay for servers and, above all, engineer time to maintain it.
• Platform tier. Some features (advanced access rules, audit logs, protected environments with approvals) are only on paid plans.

Ecosystem and extensions

• GitHub Actions Marketplace offers thousands of ready steps: cloud deploys, notifications, scanners. Pin versions and check who maintains them.
• GitLab bets on built-in features: container registry, security scanning, environments, review apps. Configs are reused through include and components.
• Jenkins has the largest plugin library, but plugins update at different paces, conflict with each other and are a common source of vulnerabilities.

What small and large teams should choose

Small team or startup:

• Code on GitHub: GitHub Actions.
• Code on GitLab: GitLab CI.
• Jenkins is rarely worth it: maintenance time costs more than any savings.

Large company:

• Everything must stay inside the perimeter: self-hosted GitLab or GitHub Enterprise with your own runners.
• Lots of legacy processes, unusual builds and existing expertise: Jenkins remains a valid option.
• Repositories spread across several hosts: Jenkins, or one platform after a migration.

Common mistakes

• Choosing CI separately from your Git host. Tight pull/merge request integration is the main benefit of built-in tools.
• Storing secrets in YAML. Use the built-in secrets and variables storage.
• Not caching dependencies. Builds become slow and expensive.
• Installing Jenkins "just in case" with nobody responsible for updating it.