In modern software development—especially open source—trust, attribution, and legality matter. One common tool to ensure proper contribution practices is the Developer Certificate of Origin (DCO).
But when exactly should you use DCO, and when is it unnecessary overhead?
Let’s break it down.
The Developer Certificate of Origin (DCO) is a simple legal statement:
" “I certify that I wrote this code or have the right to contribute it under the project's license.”
To comply with the DCO, each commit must include a line like:
Copy Signed-off-by: Your Name < you@example.co m > This line verifies authorship and intent, and it’s added using:
You’re Contributing to an Open Source Project
Many open source maintainers require it (e.g., Linux kernel, CNCF, OpenAPI, Public APIs)
GitHub bots can reject pull requests without a proper DCO sign-off
Your Project Accepts External Contributions
Corporate or Collaborative Teams with Compliance Needs
When multiple people or organizations are contributing, sign-offs create a paper trail
Especially useful in regulated environments
Participating in Programs Like GSoC
Google Summer of Code and similar programs often require DCO-compliant commits
You're Building a Personal or Private Project
If you're the only contributor, there's no legal risk
You can track your work without needing formal sign-offs
You’re in a Small Team and Trust Is High
For tight-knit teams, you might rely on GitHub attribution or internal agreements instead
You're Not Planning to Accept External Contributions
If your project is "read-only" for the public, you may skip DCO enforcement.
Pitfall How to Avoid Wrong author email in Git config Run git config user.email "your@email.com " Forgot to sign commit Use git commit -s Manual Signed-off-by mismatch Let Git auto-generate it via -s flag
If you decide to use DCO, here’s how to enforce it:
Enable the DCO GitHub App
Link: https://github.com/apps/dco
Add contribution instructions
In CONTRIBUTING.md:
Copy
## DCO Notice
## All contributions must be signed off using:
git commit -s This adds a Signed-off-by: line to your commit.
Reject unsigned commits in CI (optional)
Some teams automate this with scripts or GitHub Actions.
Scenario Use DCO? Open source contribution Yes Accepting PRs from others Yes Personal/private project No Team of trusted devs Optional GSoC or community projects Required
Using DCO is about clarity and accountability. It's a simple practice that becomes powerful when you're part of something bigger—especially in open source communities.
If you're building alone? Skip it.
If you're building for the world? Sign it.