How to Contribute to Open Source (Step-by-Step Guide)

Contributing to open source is the fastest way to build real-world engineering skills: reading unfamiliar code, following team conventions, validating changes with CI, and communicating clearly in public. It can also be intimidating—especially when your first PR is reviewed by strangers.

This guide removes guesswork with a simple, repeatable workflow you can reuse across projects. The goal is not “ship the biggest change,” but “ship the smallest change that’s clearly useful,” then learn from review and repeat.

Key Takeaways #

• Contributions are more than code: documentation, tests, triage, and reviews are legitimate contributions.
• Project health matters: choose active repos with clear contribution docs to avoid stalled PRs.
• Start small and verifiable: small PRs with evidence (“how to test”) get merged faster.
• Follow CONTRIBUTING.md exactly: most “rejected PRs” are process misses, not technical failures.
• Treat review as collaboration: your communication quality is part of the contribution.

What Counts as an Open Source Contribution? #

An open source contribution is any work that moves a public project forward. That includes:

• writing or improving documentation,
• fixing bugs or adding small features,
• adding tests,
• reporting issues with clear reproduction steps,
• reviewing PRs,
• helping users in discussions,
• translations, examples, and tutorial improvements.

If you’re new, pick contribution types that are easy to verify. Documentation and examples are often ideal because you can validate them immediately (“the doc is clearer,” “the command now works,” “the screenshot matches the UI”).

Open Source Guides captures the social challenge well:

“Contributing to open source is like walking up to a group of strangers at a party.” — Open Source Guides (GitHub)

The trick is to use the project’s existing workflows—issues, labels, PR templates, CI—so you don’t have to guess what’s expected.

Step-by-Step: How to Contribute to Open Source on GitHub #

Use this process as your default. It works for documentation, bug fixes, and small features.

1. Pick a healthy project (activity + docs + maintainer responsiveness).
2. Find a beginner-friendly issue (labels like good first issue, documentation, help wanted).
3. Confirm intent and scope in the issue thread (a short plan prevents duplicate work).
4. Set up locally using the repository’s official instructions.
5. Make a small change on a branch and run the project’s checks.
6. Open a PR with evidence (what changed, why, how to test, screenshots/logs).
7. Handle review and keep scope tight until it’s merged.

Choose a Project That Won’t Waste Your Time #

For a first contribution, “healthy” beats “famous.” A healthy project usually has:

• recent commits or merged PRs,
• maintainers who reply to issues,
• a CONTRIBUTING.md and code of conduct,
• automated checks (CI) or at least documented commands,
• clear issue templates or PR templates.

If the repo is inactive, your PR may never be reviewed no matter how good it is.

Read the Project’s Rules (Before You Touch Code) #

Many first PRs fail for a boring reason: the contributor solved the “technical” problem but skipped the project’s required process. Before you start, spend 5–10 minutes reading the repo’s rules. It prevents 80% of avoidable back-and-forth.

Look for these files (names vary by project):

• CONTRIBUTING.md: how to build, test, format, and submit changes.
• CODE_OF_CONDUCT.md: community standards for communication.
• Issue templates / PR templates: the checklist maintainers expect you to follow.
• SECURITY.md: where to report security issues (don’t file public issues for vulnerabilities).
• License files (LICENSE, COPYING): how the project is licensed and what you’re agreeing to when you contribute.

Two common “paperwork” requirements:

1. CLA (Contributor License Agreement): some projects require you to sign a CLA before maintainers can merge your PR. If a bot comments “CLA required,” do it early so your PR doesn’t stall.
2. DCO / sign-off: some projects require commits to include a “Signed-off-by” line. This is usually a simple commit option, but it’s easy to miss if you don’t read CONTRIBUTING.

None of this is bureaucracy for its own sake. Maintainers use these rules to protect the project (legal clarity, predictable quality checks, respectful communication) and to keep review time reasonable.

Quick Setup Checklist (So Your PR Doesn’t Fail CI) #

Before making any change, confirm you can run the project locally. A surprisingly high percentage of stalled PRs start with “CI is failing and I don’t know why.”

Use this checklist:

• Use the versions the project expects (language runtime, package manager, toolchain).
• Install dependencies exactly as documented.
• Run the test suite once before your change (baseline).
• Run lint/format commands if they exist (baseline).
• Make your change and re-run the same checks.
• If checks are slow, at least run the smallest “pre-commit” subset locally.

If setup fails, that’s still a valid contribution: improve setup docs, pin a dependency, or add a “known issues” section—after confirming with maintainers what they want.

Find the Right Issue (Beginner-Friendly, Not Just Easy) #

Start with labels because they reflect maintainer intent.

Use GitHub search qualifiers to filter issues #

Examples you can adapt:

is:issue is:open label:"good first issue"
is:issue is:open label:documentation
repo:OWNER/REPO is:issue is:open label:"help wanted"

If you’re unsure whether an issue is still available, comment before you start:

Hi! I’d like to work on this. My plan:
1) Reproduce the issue on the latest version
2) Add/adjust a test to capture expected behavior
3) Implement a minimal fix and run the test suite
I’ll share progress here if I hit blockers.

This is polite, avoids duplicated work, and signals that you understand the workflow.

Make the Change: Fork, Branch, Validate #

Most projects accept contributions through forks. The standard workflow:

1. Fork the repository to your account.
2. Clone your fork locally.
3. Create a feature branch.
4. Make a small change and run tests/lint.
5. Push the branch to your fork.
6. Open a PR from your fork to the upstream repo.

If your fork falls behind, sync it periodically. This reduces merge conflicts and keeps your PR aligned with current code.

Paraphrased: For many projects, you contribute by creating changes in a fork and opening a pull request back to the original repository. — GitHub Docs, adapted

Keep Your Fork and Branch Up to Date (Without Breaking Review) #

When your PR is open for more than a day or two, the upstream repository may move forward. If your branch is far behind, CI can fail and merge conflicts become more likely. That’s why “syncing your fork” is a normal maintenance step for contributors.

A practical approach:

1. Sync your fork’s default branch with upstream (often main or master).
2. Update your feature branch only when needed:
   • If there are no conflicts, updating can fix CI failures caused by upstream changes.
   • If updating introduces conflicts, resolve them carefully and re-run tests.

One caution: changing history can confuse reviewers. In many projects, rebasing and force-pushing after review has started can invalidate review comments and make it harder to follow what changed. If you must rewrite history, explain why in the PR thread and keep the diff as small as possible.

If you’re not sure what the project prefers, follow CONTRIBUTING.md. Some maintainers prefer “merge upstream into your branch,” others prefer “rebase,” and many don’t care as long as the PR stays reviewable and CI stays green.

After you sync, treat it like a new change: re-run the project’s test and lint commands locally (or at least check the CI results) and update your PR description if anything about “how to test” changed. This habit prevents “it worked yesterday” surprises.

Open a PR That Maintainers Can Review Quickly #

A high-quality PR has three properties: clarity, verification, and scope control.

PR description template (recommended) #

## Summary
What changed?

## Motivation
Why is this change needed? Link to the issue.

## How to test
Commands you ran, expected output, screenshots/logs.

## Notes
Trade-offs, edge cases, follow-ups (if any).

If your PR fixes a bug, a regression test is one of the strongest trust signals you can provide.

Handle Code Review Like a Pro #

Review is where most learning happens. A few habits make review smoother:

• Respond to comments promptly (even if it’s “I’m working on it”).
• Keep changes focused on the original scope until merge.
• If you disagree, explain trade-offs and ask what the maintainer prefers.
• Don’t take comments personally—review is collaboration, not judgment.

If CI is failing, fix it quickly or explain why it’s failing. Unattended failing PRs are often deprioritized or closed.

Comparison Table: Common Ways to Contribute #

Common Mistakes (And How to Avoid Them) #

1. Not reading CONTRIBUTING.md: missing formatting rules, test commands, or CLA/DCO requirements.
2. Starting too big: large PRs are hard to review and easy to reject.
3. No verification evidence: maintainers need “how to test,” not “trust me.”
4. Changing unrelated files: “while I’m here” refactors make review harder.
5. Poor communication: vague descriptions and slow responses stall PRs.

Frequently Asked Questions #

What counts as an open source contribution? #

Any work that moves a public project forward: code, docs, tests, triage, bug reports, reviews, translations, and community support.

Do I need permission before contributing? #

Usually you can start by opening an issue or PR, but you should read CONTRIBUTING.md first. Some projects require CLAs, DCO sign-offs, or specific tooling before changes can be merged.

What’s the easiest first contribution? #

Documentation fixes, broken examples, and small test improvements are often the fastest first contributions because they’re low risk and easy to verify.

Why do PRs get stuck or rejected? #

Most rejections are process and clarity problems: unclear scope, missing verification, not following guidelines, or low-context communication.

What if nobody reviews my PR? #

First, make sure CI is green and your PR description includes “how to test.” Then politely ping after a reasonable wait. If the repository is inactive, it’s OK to close your PR and choose a healthier project.

Conclusion #

To contribute successfully, optimize for maintainer time: pick healthy projects, choose well-scoped issues, follow the contribution docs, and ship small changes with strong verification. Do that consistently, and your first PR becomes a repeatable skill—not a one-time milestone.

References #

1. Open Source Guides (GitHub): How to Contribute to Open Source
2. GitHub Docs: Finding ways to contribute to open source on GitHub
3. GitHub Docs: Creating a pull request from a fork
4. GitHub Docs: Syncing a fork
5. GitHub Docs: About pull request reviews
6. GitHub Docs: Using search to filter issues and pull requests