What Are GitHub Actions? A Quick Guide

GitHub runs over 71 million CI/CD jobs every single day. If you are still configuring a separate build server to test and deploy code, you are solving a problem that GitHub already solved for you.

So what are GitHub Actions, and why have millions of developers switched to them? GitHub Actions is an automation platform built directly into your repository. It handles everything from running automated tests on a pull request to deploying finished code to production, all triggered by events inside your workflow.

This guide covers how workflows actually work, what people use Actions for beyond basic CI/CD, how pricing breaks down, and the security risks your team needs to watch for. Whether you are setting up your first workflow or evaluating Actions against tools like Jenkins or GitLab CI/CD, the goal here is to give you the full picture without the fluff.

What Are GitHub Actions

GitHub Actions is a CI/CD and workflow automation platform built directly into GitHub repositories. It lets developers automate tasks like testing, building, and deploying code without leaving the platform where their codebase already lives.

Think of it this way. You push code to your repository, and GitHub Actions picks it up automatically, runs your tests, checks for errors, and deploys the result. No separate CI server to configure. No third-party tool to connect.

Microsoft acquired GitHub in 2018 for $7.5 billion and launched Actions shortly after. The platform now processes over 5 million workflow runs per day, according to CoinLaw’s 2026 GitHub statistics report. That number was up 40% year-over-year.

Workflows execute on GitHub-hosted runners (Ubuntu, Windows, macOS) or self-hosted runners for teams that need custom environments. The free tier gives public repositories unlimited minutes. Private repos get 2,000 minutes per month on the free plan, with additional minutes billed per-use on paid tiers.

GitHub Enterprise is now adopted by 92% of Fortune 100 companies, per CoinLaw. Actions is a big part of that adoption, especially as teams move toward automating their entire software development process.

The Marketplace passed 10,000 published actions in 2024, according to the GitHub Blog. That number has kept climbing, with the broader Marketplace tools count now exceeding 1,500 integrations across 32 categories.

And the bigger picture? The CI/CD tools market hit an estimated $8.17 billion in 2024, per Market Research Future. It is projected to reach $38.75 billion by 2035 at a 15.19% CAGR. GitHub Actions sits at the center of that growth because it removes the friction of setting up separate build infrastructure.

How GitHub Actions Workflows Work

A GitHub Actions workflow is a YAML file. You drop it into the .github/workflows/ directory inside your repository, and GitHub picks it up automatically.

Each workflow file defines one or more jobs. Each job runs on its own runner (a virtual machine or container). Inside each job, you define steps. Steps either run shell commands or call reusable actions from the Marketplace.

Jobs can run in parallel by default, or you can chain them sequentially using the needs keyword. That dependency system is actually one of the tricky parts. Getting it wrong means your deploy job starts before your test job finishes. Took me a while to get comfortable with that when I first set it up.

Here is the basic structure:

The Mordor Intelligence CI tools market report notes that enterprises are increasingly collapsing build, test, and deploy into a single automated workflow. GitHub Actions was designed for exactly that. One YAML file can cover your entire build pipeline, from linting through production deployment.

Workflow Triggers and Events

Workflows don’t run on their own. Something has to trigger them.

The most common triggers are push and pullrequest. But GitHub supports dozens of event types, and you can filter triggers by branch, file path, or tag. So if you only want tests to run when someone changes files in the /src directory, you set that up in the YAML.

Common trigger types:

• push and pullrequest for code changes
• schedule for cron-based runs (dependency updates, cleanup tasks)
• workflowdispatch for manual triggers with custom input parameters
• repositorydispatch for webhooks from external systems

The manual dispatch feature is underrated. You can set up input fields so team members trigger workflows with specific parameters without touching the command line. Good for one-off deployments or maintenance scripts.

Jobs, Steps, and Runners

GitHub-hosted runners come preconfigured with common tools and SDKs. Ubuntu runners are the cheapest per-minute. macOS runners cost roughly 10x more. Windows falls in between.

Self-hosted runners are for teams that need specific hardware, custom software, or want to avoid per-minute charges entirely. You install the runner agent on your own infrastructure, and GitHub sends jobs to it. A build engineer typically manages these in larger organizations.

Steps within a job share the same runner filesystem, so one step can produce a file and the next step can read it. But jobs are isolated. Passing data between jobs requires artifacts or output variables.

CoinLaw reports that containerization and Kubernetes usage in Actions workflows rose 45% recently, with roughly 1 million workflows now involving containerized applications.

What Are GitHub Actions Used For

The obvious answer is CI/CD. But honestly, that only covers about half of what people actually do with Actions.

Running automated tests on every push or pull request is the most common use case. You commit code, the workflow fires, your unit testing suite runs, and you get a green checkmark or a failure notification. That feedback loop changes how teams work.

Then there is continuous deployment. Actions can push builds to AWS, Azure, Google Cloud, Vercel, Netlify, or basically any hosting provider with an API. One push to the main branch, and your code is live.

But the less obvious stuff is where it gets interesting:

• Code quality enforcement: Linting, formatting checks, and static analysis run automatically on every PR
• Issue management: Auto-labeling issues, greeting first-time contributors, closing stale issues
• Scheduled maintenance: Dependency updates via Dependabot, database backups, certificate renewals
• Release automation: Generating changelogs, building build artifacts, publishing packages to npm or PyPI

Shopify, for example, uses GitHub Actions across its engineering organization for both code testing and operational automation. Their deployment pipeline runs thousands of workflows daily.

Electroiq’s 2025 GitHub report shows Actions has cut deployment times by an average of 30% for organizations using the platform, which makes sense when you consider how much time gets lost switching between disconnected tools.

GitHub Actions vs. Other CI/CD Tools

The CI/CD market is crowded. Jenkins, GitLab CI/CD, CircleCI, Travis CI. They all solve similar problems. The difference is in the trade-offs.

GitHub Actions wins on integration. If your code is on GitHub (and for 180+ million developers, it is), you already have CI/CD available. Zero external accounts. No webhook configuration. No API tokens to rotate between platforms.

Jenkins is still the go-to for teams that need total control over their build infrastructure. But it comes with post-deployment maintenance overhead that most small and mid-size teams do not want to deal with. You are running your own servers, managing plugins, handling security patches yourself.

GitLab CI/CD is the closest competitor in terms of approach. Similar YAML syntax. Similar runner model. But it only makes sense if your repos are on GitLab. Moving your entire source control management setup for CI/CD is rarely worth it.

CircleCI and Travis CI are solid SaaS options, but they add another vendor relationship. The CD Foundation’s 2024 State of CI/CD Report found that using multiple CI/CD tools of the same form actually worsens deployment performance, likely due to interoperability friction. Consolidating onto one platform tends to produce better results.

Where Actions falls short? Complex monorepo setups. If you are running something like Nx or Turborepo across a massive codebase, you might need more granular control over cache invalidation and task scheduling than Actions provides out of the box.

The GitHub Actions Marketplace

The Marketplace is what makes Actions more than just a CI/CD runner. It is a library of pre-built, reusable automation components that anyone can publish or consume.

GitHub announced in 2024 that the Marketplace had crossed 10,000 published actions. SQ Magazine’s research indicates the broader ecosystem (including apps and integrations) is expanding by roughly 41% annually.

You reference a Marketplace action in your workflow file using the uses: keyword. Like this:

uses: actions/checkout@v4

That pulls in the official checkout action at version 4. Simple.

Popular categories and actions:

• Code checkout: actions/checkout (used in nearly every workflow)
• Language setup: actions/setup-node, actions/setup-python, actions/setup-java
• Container builds: docker/build-push-action
• Security scanning: CodeQL, Snyk, Trivy
• Deployment: AWS, Azure, GCP, and Vercel deploy actions

Verification matters. Actions with a verified creator badge mean GitHub has confirmed the publisher is a legitimate partner organization. For everything else, you are trusting community-maintained code.

And that trust issue is real. The tj-actions/changed-files supply chain attack in March 2025 (CVE-2025-30066) compromised over 23,000 repositories by injecting malicious code through modified version tags. CISA issued a formal advisory. The attack exposed secrets like access keys, GitHub PATs, and npm tokens through workflow logs.

Best practice? Pin actions to full commit SHAs instead of version tags. Version tags can be modified after the fact. A SHA cannot. This is the kind of thing your team’s code review process should catch before merging workflow changes.

How to Create a Custom GitHub Action

Sometimes the Marketplace does not have what you need. Or the existing action does too much, or not enough. That is when you build your own.

Every custom action starts with an action.yml file. This metadata file defines your action’s name, description, inputs, outputs, and how it runs.

There are three types of custom actions, and picking the right one matters more than most guides let on.

JavaScript actions run directly on the runner without any container overhead. They are fast, cross-platform, and the best choice for most use cases. If your action needs to interact with the GitHub API, parse files, or run logic, start here.

Docker container actions package your code inside a container. Full environment control. You can install any dependencies, use any runtime. The trade-off is startup time. Pulling and building a container on every run adds seconds (or minutes, depending on image size). But for teams already deep into containerization, this model keeps everything consistent.

Composite actions combine multiple steps into a single reusable unit. No code to write. You are just grouping existing steps and actions together. Perfect for standardizing workflows across repos without duplicating YAML everywhere.

The DevOps Institute’s 2024 report found that over 57% of organizations struggle to fill qualified CI/CD roles. Building custom actions well requires understanding YAML syntax, the GitHub Actions API, and configuration management principles. It is not hard, but it is not trivial either.

Once your action is ready, you can keep it private within your organization or publish it to the Marketplace. Publishing follows a straightforward process through the repository settings, and you will want to use semantic versioning for your releases so consumers can pin to stable versions.

If your team follows test-driven development, you can apply the same approach to custom actions. Write tests for your action logic, run them in a workflow, and validate behavior before publishing updates. Your mileage may vary on how thorough this needs to be, but at least basic smoke tests prevent embarrassing breakages.

GitHub Actions Pricing and Usage Limits

Pricing is where GitHub Actions gets a bit tricky. The free tier is generous. But once you are running private repos at scale, costs add up faster than most teams expect.

Public repositories get unlimited free minutes on standard GitHub-hosted runners. That is a huge deal for open-source projects. Private repos are where billing kicks in.

Once you burn through your free minutes, you pay per-minute based on the runner OS. Linux is the cheapest. macOS costs roughly 10x more per minute than Linux. Windows is about 2x.

GitHub Docs confirm that storage limits are shared between Actions artifacts, Actions caches, and GitHub Packages. So your total storage across all three cannot exceed what your plan includes.

In January 2026, GitHub reduced hosted runner prices by up to 39% depending on machine type, according to their official changelog. That made larger runners more accessible for heavy CI workloads and build automation.

Here is the part that caught a lot of developers off guard. GitHub also announced a $0.002 per-minute platform charge for self-hosted runners in private repos, effective March 2026. After significant community backlash (The Register covered the controversy), GitHub postponed the change to re-evaluate.

WarpBuild’s analysis notes that developers used 11.5 billion total Actions minutes in public projects during 2025, representing roughly $184 million in free compute. That gives you a sense of the scale GitHub is operating at and why pricing adjustments keep happening.

Billing tip: Set spending limits on your GitHub organization. If you do not, a runaway workflow (say, one stuck in a loop) can burn through minutes overnight. GitHub rounds every job up to the nearest whole minute, so short jobs with frequent triggers can cost more than you would expect.

Security Considerations for GitHub Actions

Security in GitHub Actions is not optional. It is the thing that will burn you if you treat it as an afterthought.

The March 2025 supply chain attack on tj-actions/changed-files (CVE-2025-30066) proved that. CISA issued a formal alert. Over 23,000 repositories were compromised. The attack exposed secrets like AWS access keys, GitHub Personal Access Tokens, and npm tokens through public workflow logs.

And that was not an isolated incident. Dark Reading reported at Black Hat Europe 2025 that supply chain attacks targeting GitHub Actions increased throughout 2025, with researchers from Wiz presenting multiple cases where attackers exploited misconfigured workflows to steal credentials.

Secrets Management

Repository secrets are encrypted and only exposed to workflows at runtime. GitHub automatically redacts secret values from workflow logs. But that redaction is not foolproof.

StepSecurity’s security guide recommends using OpenID Connect (OIDC) instead of storing static credentials as secrets. With OIDC, your workflows generate short-lived identity tokens for AWS, Azure, or GCP, removing the need for long-lived access keys entirely.

Environment secrets add another layer. You can require manual approval before a workflow accesses production credentials. That stops a compromised workflow from deploying to your production environment without a human in the loop.

GITHUBTOKEN Permissions

Every workflow job gets an auto-generated GITHUBTOKEN. It expires when the job finishes.

GitHub Docs recommend setting the default permission to read-only, then increasing permissions per-job as needed. The principle of least privilege applies directly here. A job that only needs to read code should not have write access to your repository.

GitGuardian’s security cheat sheet warns that broad GITHUBTOKEN permissions remain the number one cause of token-based leakage in CI/CD pipelines. Prior to February 2023, the default permission was set to read-write, which GitHub has since changed for new repositories.

Third-Party Action Risks

A CNCF Security SIG survey found that 34% of CI/CD incidents traced back to unpinned or outdated dependencies, according to MoldStud’s analysis of common GitHub Actions mistakes.

Pinning actions to full commit SHAs is the only truly immutable reference. Version tags can be rewritten (which is exactly what happened in the tj-actions attack). A tag like v4 can point to different commits over time. A SHA cannot be changed.

Wiz’s hardening guide puts it bluntly: minimize use of third-party actions entirely. When you do use them, check contributor count, code complexity, and whether the action follows its own development best practices.

Common Mistakes and Limitations of GitHub Actions

GitHub Actions has real limitations. Knowing them upfront saves you from hitting walls mid-project.

YAML Syntax Errors

YAML is sensitive to indentation. A single wrong space can break an entire workflow, and the error messages are not always helpful.

The frustrating part? There is no built-in way to validate a workflow file before pushing it. You push, it breaks, you fix, you push again. Tools like linters and the YAML Validator help, but they do not catch every Actions-specific issue. GitHub finally added YAML anchor support in September 2025, but without merge key support, the feature feels incomplete.

Minute Overruns on Private Repos

MoldStud’s research shows that workflows using parallelization reduce run time by up to 47% on average. The flip side: more parallel jobs means more minutes consumed simultaneously.

Teams running frequent CI on private repos often blow through their free minutes by mid-month without realizing it. macOS runners are the worst offenders because of the minute multiplier. One 10-minute macOS job costs the same as roughly 100 minutes of Linux time.

Monorepo Challenges

This is where GitHub Actions gets genuinely painful.

A developer at Ninkovic.dev published a detailed breakdown of the problem in early 2025. In a monorepo setup, you typically want to run different workflows for different subdirectories. GitHub’s paths filter handles triggering. But the required status checks system does not play well with conditional workflows.

If a required check only runs when certain files change, and a PR does not touch those files, the check never runs. The PR gets stuck waiting for a status that will never arrive. You end up needing workaround workflows that just report “skipped” status so the PR can merge. Tools like Nx and Turborepo handle monorepo CI natively and do not have this problem.

No Local Execution

You cannot run GitHub Actions locally. There is a community tool called act that tries to simulate the runner environment on your machine, but support is limited and it does not replicate every GitHub-hosted runner behavior.

That means your feedback loop for workflow debugging is: edit YAML, commit, push, wait for the run, check logs, repeat. For complex workflows (especially ones involving matrix builds or deployment pipelines), this cycle gets slow. A lot of teams working with DevOps practices have flagged this as their biggest pain point.

Concurrency and Resource Conflicts

Multiple workflows triggered by the same event can step on each other. Two deploys to the same environment at once. Two workflows writing to the same artifact store.

GitHub provides a concurrency key in YAML to handle this. You group workflows by a concurrency identifier, and GitHub cancels or queues duplicate runs. But most teams do not set this up until after something breaks. Part of the software configuration management discipline is getting these controls in place before they are needed, not after.

GitHub’s own architecture modernization has helped here. Their 2025 re-architecture now handles 71 million jobs per day (up from 23 million in early 2024), and individual enterprises can start 7x more jobs per minute than before. Scale is less of a bottleneck now. But workflow logic errors are still on you.

FAQ on What Are GitHub Actions

What are GitHub Actions in simple terms?

GitHub Actions is an automation platform built into GitHub. It runs tasks like testing, building, and deploying code automatically when specific events happen in your repository. Think of it as CI/CD without a separate tool.

Are GitHub Actions free to use?

Public repositories get unlimited free minutes on standard runners. Private repos include a monthly free tier (2,000 minutes on the Free plan). After that, you pay per-minute based on runner OS.

What language are GitHub Actions workflows written in?

Workflows use YAML configuration files stored in your repository’s .github/workflows/ directory. Each file defines triggers, jobs, steps, and runner environments. No proprietary scripting language needed.

Can GitHub Actions replace Jenkins?

For most teams, yes. GitHub Actions handles CI/CD without the overhead of managing your own build server. Jenkins still makes sense if you need deep plugin customization or run entirely on-premises infrastructure.

What triggers a GitHub Actions workflow?

Common triggers include push, pullrequest, cron schedules, and manual dispatch. GitHub supports dozens of webhook events, and you can filter triggers by branch, file path, or tag.

What is the GitHub Actions Marketplace?

A library of over 10,000 pre-built, reusable actions published by GitHub, verified partners, and the open-source community. You reference them in your workflow file using the uses: keyword.

How do GitHub-hosted and self-hosted runners differ?

GitHub-hosted runners are managed virtual machines (Ubuntu, Windows, macOS) that GitHub maintains. Self-hosted runners run on your own infrastructure, giving you full control over the environment but requiring your own maintenance.

Is GitHub Actions secure?

It includes encrypted secrets, scoped token permissions, and environment protection rules. But third-party actions carry supply chain risk. Always pin actions to commit SHAs and follow the principle of least privilege for tokens.

Can GitHub Actions deploy to cloud providers?

Yes. There are official and community-maintained actions for deploying to AWS, Azure, Google Cloud, Vercel, and Netlify. Most cloud providers also support OIDC authentication for credentialless deployments from Actions.

What are the main limitations of GitHub Actions?

No local execution for debugging workflows. Limited native monorepo support. YAML syntax errors fail silently. macOS runners are expensive. And the 6-hour maximum job execution time can block long-running tasks.

Conclusion

Understanding what are GitHub Actions comes down to one thing: automation that lives where your code already lives. No external CI server. No extra vendor. Just YAML files in your repository that handle everything from running test suites to pushing releases to production.

The platform handles over 71 million jobs daily across millions of repositories. The Marketplace gives you access to thousands of reusable workflow components. And the pricing model works for solo developers and enterprise teams alike.

But it is not without trade-offs. Security demands attention, especially around third-party actions and secrets management. Monorepo support still has rough edges. YAML debugging remains slow without local execution.

Start with a simple workflow. Automate your test suite on every pull request. Build from there. The release cycle gets faster once your pipeline runs itself.

• Author
• Recent Posts

Bogdan Sandu

Bogdan Sandu specializes in web design, focusing on creating user-friendly websites, and innovative UI kits.

Many of his resources are available on various design marketplaces and for free on Codepen.

Over the years, he's worked with a range of clients and contributed to design publications like Design Your Way, Designmodo, WebDesignerDepot, WPDean, and Speckyboy, and Slider Revolution among others.

Latest posts by Bogdan Sandu (see all)

• Ai Pair Programming: The New Way To Write Code - April 12, 2026
• What Is Agentic Coding? The Next AI Dev Workflow - April 10, 2026
• From Setup To Monitoring: Why A DMARC Service Matters - April 10, 2026