If “CI/CD” sounds like something you should know but don’t know where to start, this guide is for you. GitHub Actions makes continuous integration and delivery accessible to everyone with a GitHub repository.
What is GitHub Actions?
GitHub Actions is a CI/CD platform built directly into GitHub. It lets you automate testing, building, and deploying right from your repository. Workflows trigger on pushes, pull requests, or scheduled events.
1. Workflow Basics
Place a YAML file inside .github/workflows/ to define your workflow.
.github/
└── workflows/
└── ci.yml
Here’s the basic structure:
name: CI
on:
push:
branches: [main]
pull_request:
branches: [main]
jobs:
test:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- name: Setup Node.js
uses: actions/setup-node@v4
with:
node-version: 20
- run: npm ci
- run: npm test
Key Elements
| Element | Description |
|---|---|
name | Workflow name shown on GitHub |
on | Trigger events (push, pull_request, schedule, etc.) |
jobs | Collection of jobs that can run in parallel |
runs-on | Runner environment (ubuntu-latest, windows-latest, macos-latest) |
steps | Individual tasks within a job |
uses | Reuse an existing action |
run | Execute a shell command directly |
2. Trigger Variations
# On push
on: push
# On pull request
on: pull_request
# Scheduled (cron)
on:
schedule:
- cron: '0 9 * * 1' # Every Monday at 9:00 UTC
# Manual trigger
on:
workflow_dispatch:
3. Using Marketplace Actions
Thousands of actions are available on GitHub Marketplace. Here are the most common ones:
- uses: actions/checkout@v4 # Checkout repository
- uses: actions/setup-node@v4 # Setup Node.js
- uses: actions/setup-python@v5 # Setup Python
- uses: docker/login-action@v3 # Login to Docker registry
- uses: actions/cache@v4 # Cache dependencies
- uses: actions/upload-artifact@v4 # Upload build artifacts
4. Matrix Builds for Parallel Testing
jobs:
test:
runs-on: ubuntu-latest
strategy:
matrix:
node-version: [18, 20, 22]
os: [ubuntu-latest, windows-latest]
runs-on: ${{ matrix.os }}
steps:
- uses: actions/checkout@v4
- uses: actions/setup-node@v4
with:
node-version: ${{ matrix.node-version }}
- run: npm ci
- run: npm test
That’s six combinations running automatically.
5. Secrets and Environment Variables
Store API keys and passwords in Settings → Secrets and variables → Actions on GitHub.
jobs:
deploy:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- run: deploy.sh
env:
API_KEY: ${{ secrets.API_KEY }}
DEPLOY_TOKEN: ${{ secrets.DEPLOY_TOKEN }}
Never write secrets directly into your YAML files.
6. Caching Dependencies
Caching node_modules or ~/.npm can significantly speed up your workflows.
- name: Cache Node Modules
uses: actions/cache@v4
with:
path: ~/.npm
key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
restore-keys: |
${{ runner.os }}-node-
7. Deployment Example (GitHub Pages)
name: Deploy to GitHub Pages
on:
push:
branches: [main]
permissions:
contents: read
pages: write
id-token: write
jobs:
deploy:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- uses: actions/setup-node@v4
with:
node-version: 20
- run: npm ci
- run: npm run build
- uses: actions/configure-pages@v4
- uses: actions/upload-pages-artifact@v3
with:
path: ./out
- uses: actions/deploy-pages@v4
Summary
GitHub Actions is one of the easiest CI/CD tools to get started with — just drop a YAML file into .github/workflows/. Start with a simple “run tests on push” workflow, then gradually explore matrix builds, caching, and automated deployments.