GitHub Actions vs GitLab CI: A Practical Comparison

# GitHub Actions vs GitLab CI: A Practical Comparison

I've spent the last two years working with both GitHub Actions and GitLab CI across multiple projects. Here's what I've learned about each platform, minus the marketing fluff.

The Context

Our team manages about 50 microservices across different repositories. Some are on GitHub, some on GitLab. This gave me a unique perspective on both platforms under real production workloads.

Syntax & Configuration

GitHub Actions

name: CI Pipeline
on:
  push:
    branches: [main]
  pull_request:

  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

• *Pros:**

• YAML is straightforward and readable
• Reusable actions from marketplace
• Matrix builds are elegant

• *Cons:**

• Nested structure can get verbose
• Environment variables handling is quirky

GitLab CI

stages:
  - test
  - build

  stage: test
  image: node:20
  script:
    - npm ci
    - npm test
  only:
    - main
    - merge_requests

• *Pros:**

• Flatter YAML structure
• Built-in Docker support
• Stages concept is intuitive

• *Cons:**

• Less reusable components
• Needs more manual configuration

Performance & Speed

Build Times

In my experience:

• **GitHub Actions**: ~3-5 minutes for typical Node.js app
• **GitLab CI**: ~4-6 minutes for same app

GitHub Actions edges ahead slightly, but the difference is marginal.

Parallelization

Both handle parallel jobs well. GitHub Actions has cleaner syntax for matrix builds:

strategy:
  matrix:
    node-version: [18, 20, 22]
    os: [ubuntu-latest, windows-latest]

GitLab requires more manual setup for the same result.

Ecosystem & Marketplace

GitHub Actions Marketplace

This is where GitHub shines. Over 20,000 actions available:

- uses: actions/cache@v4
  with:
    path: ~/.npm
    key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}

One line, and you have intelligent caching. Beautiful.

GitLab's Approach

GitLab doesn't have a marketplace. Instead, you write more scripts or use Docker images:

test:
  image: node:20
  cache:
    key: ${CI_COMMIT_REF_SLUG}
    paths:
      - node_modules/
  script:
    - npm ci
    - npm test

More control, but more work.

Docker Integration

GitLab CI Wins Here

GitLab CI was built with Docker in mind:

build:
  image: docker:latest
  services:
    - docker:dind
  script:
    - docker build -t myapp .
    - docker push myapp

It just works. No weird permissions issues.

GitHub Actions

Needs more setup for Docker:

- name: Set up Docker Buildx
  uses: docker/setup-buildx-action@v3
- name: Build and push
  uses: docker/build-push-action@v5
  with:
    context: .
    push: true
    tags: myapp:latest

Works fine, but requires more marketplace actions.

Secrets Management

GitHub

env:
  API_KEY: ${{ secrets.API_KEY }}

Simple. Secrets are org/repo scoped. Works well.

GitLab

variables:
  API_KEY: $CI_DEPLOY_TOKEN

More flexible with group-level variables and environments. Better for complex setups.

Cost

GitHub Actions

• 2,000 minutes/month free for private repos
• Public repos: unlimited
• Additional minutes: $0.008/minute

GitLab CI

• 400 minutes/month free (SaaS)
• Self-hosted runners: unlimited
• Additional minutes: $10/1000 minutes

• *Winner:** If you can self-host, GitLab CI is cheaper at scale.

Self-Hosted Runners

GitHub

./config.sh --url https://github.com/org/repo --token TOKEN
./run.sh

Setup is straightforward. Runners are repo or org-scoped.

GitLab

gitlab-runner register
gitlab-runner run

More flexible. Can be project, group, or instance-wide. Better for large organizations.

Debugging Experience

GitHub Actions

• Logs are clear and searchable
• Re-run individual jobs
• Debug mode available with secrets
• Can SSH into runners (with action)

GitLab CI

• Excellent log viewer
• Can retry individual jobs
• **Interactive debugging**: SSH or web terminal
• Artifacts browsing is superior

• *Winner:** GitLab's interactive debugging is a game-changer.

Real World Decision Matrix

• *Choose GitHub Actions if:**

• You're already on GitHub
• You want extensive marketplace integrations
• You prefer minimal configuration
• Your team is small to medium

• *Choose GitLab CI if:**

• You need advanced Docker workflows
• You want self-hosted runners at scale
• You need complex deployment strategies
• You require better debugging tools

My Setup

I use both:

• **GitHub Actions** for open-source projects and frontend apps
• **GitLab CI** for infrastructure code and complex deployments

Common Pitfalls

GitHub Actions

1. **Workflow file limits**: Max 3 hours per job
2. **Artifact retention**: Only 90 days
3. **Concurrent jobs**: Limited on free tier

GitLab CI

1. **Shared runners**: Can be slow during peak times
2. **Docker socket**: Needs `docker:dind` service
3. **Variables**: Complex precedence rules

Migration Tips

GitHub → GitLab

# GitHub
- uses: actions/checkout@v4

GitLab equivalent git clone $CI_REPOSITORY_URL cd $CI_PROJECT_NAME ```

GitLab → GitHub

Most scripts translate directly, but marketplace actions can simplify a lot.

Final Thoughts

Both are excellent CI/CD platforms. GitHub Actions wins on simplicity and ecosystem. GitLab CI wins on flexibility and debugging.

My advice? If you're starting fresh, go with your git platform. The integration is seamless, and you avoid context switching.

• *Pro tip:** Regardless of choice, invest time in making your pipelines fast. A slow CI/CD is worse than no CI/CD.

What's your experience? Any gotchas I missed? Let me know!