Introduction to CI/CD with GitHub Actions

CI/CD means that every change you push is built and tested automatically (continuous integration), and that every change which passes can be released by a script instead of by hand (continuous delivery and deployment). GitHub Actions is the CI/CD system built into GitHub: you describe the automation in YAML files in your repository, and GitHub runs them on machines called runners when something happens, such as a push or a pull request.

This guide teaches GitHub Actions by building one pipeline from the first line. The example app is a small Node.js site, a one-page command cheatsheet. By the last part, every pull request is linted and tested on Linux, Windows, macOS and arm64 runners, merges go through a merge queue, and every change on main is deployed to GitHub Pages after an approval and checked on the live site.

Every run log, timing, error message and gh output in this guide is real. It comes from the companion repository, where the workflows ran on 24 October 2026, so the outputs show its name, The-DevOps-Daily/guide-cicd-demo-2026-10-24. When you follow along in your own repository, your run IDs, times and names will differ.

What You Will Learn

Part	What you do
1. Your first workflow	Learn what CI/CD means, push a first workflow and read its logs
2. Workflow syntax	Use triggers, manual inputs, jobs, outputs, expressions and conditions
3. Build and test	Lint, test on three Node.js versions and build the app on every pull request
4. Caching and artifacts	Cache npm downloads and pass the built site between jobs
5. Variables, secrets and OIDC	Keep configuration and credentials out of the code, and replace cloud keys with OIDC
6. Deployments	Deploy to GitHub Pages through a protected environment, smoke test it and roll back
7. Matrices, reuse and merge queues	Test on Linux, Windows, macOS and arm64, share code with reusable workflows and use a merge queue
8. Debugging and speed	Read failures, re-run with debug logs, write job summaries and make runs faster
9. Security	Limit the token, avoid script injection and unsafe triggers, and pin actions to commits
10. The complete pipeline	Put it all together and see patterns for Docker images, Terraform and Kubernetes

What Changed Since This Guide Was First Written

The first version of this guide is from February 2025. GitHub Actions has changed a lot since then. If you have older workflows, these are the changes most likely to affect them:

Before	Now (October 2026)	Since
actions/checkout@v4, actions/setup-node@v4	checkout@v7 and setup-node@v7; JavaScript actions run on Node.js 24	June and July 2026
Actions that run on Node.js 20	Node.js 20 is removed from the runners; old actions must be upgraded	23 September 2026
upload-artifact@v3 and download-artifact@v3	v3 stopped working; current versions are upload-artifact@v7 and download-artifact@v8	30 January 2025
actions/cache on the old cache service	A new cache service; actions/cache older than v4.2.0 (or v3.4.0) fails	February to April 2025
ubuntu-latest is Ubuntu 24.04	ubuntu-latest moves to Ubuntu 26.04, gradually	19 October to 19 November 2026
x64 runners only	Linux and Windows arm64 runners (ubuntu-24.04-arm, windows-11-arm), in private repositories too	August 2025 and January 2026
Fork code checked out in pull_request_target workflows	checkout@v7 refuses to check out fork pull requests in pull_request_target and workflow_run	June 2026
Steps always run one after another	parallel and background steps	June 2026
./ to call an action from the same repository	$/ resolves to the commit that is running, with no checkout	July 2026
Linux 2-core minutes at $0.008	$0.006 per minute; a planned fee for self-hosted runners was postponed	1 January 2026

Each part explains the changes that belong to it, with links to GitHub's announcements.

What It Costs

Standard GitHub-hosted runners are free in public repositories. For private repositories, your account or organization gets a monthly allowance that all of them share: 2,000 minutes on GitHub Free and 3,000 on Pro and Team. After that you pay per minute, for example $0.006 for a Linux 2-core runner, $0.010 for Windows and $0.062 for macOS (GitHub's price list, October 2026). GitHub reduced these prices by up to 39% on 1 January 2026. It also announced a $0.002 per minute charge for self-hosted runners, then postponed it to re-evaluate; as of October 2026, self-hosted runners are still free to use. Everything in this guide runs on free runners in a public repository.

Prerequisites

• A GitHub account and a repository you can push to. A public repository keeps everything free.
• Git on your computer, and basic Git and pull request experience. The Git guide covers it.
• Node.js 24, or 22.13 and newer in the 22 line, to run the example app locally.
• The GitHub CLI (gh). The guide uses it to watch runs and read logs; every step also works in the web interface.

No CI/CD experience is needed. The example app is short, and Part 3 explains every file.

Practice Hands-On

Design a pipeline in your browser with the CI/CD Stack Generator, see why YAML surprises people in the YAML Parsing Simulator, then test yourself with the GitHub Actions Workflows Quiz and the CI/CD Concepts flashcards.

Keep Learning

• Jenkins vs GitHub Actions and GitLab CI vs GitHub Actions
• CI/CD Pipeline Setup Checklist
• Complete CI/CD Pipeline with GitHub Actions (exercise)
• Next guides: Introduction to Docker and Security Gates

Start with Part 1: What Is CI/CD? Your First GitHub Actions Workflow.