When to Use DCO (Developer Certificate of Origin) – And When You Don’t Need To

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.

What Is a DCO?

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:

Signed-off-by: Your Name <you@example.com>

This line verifies authorship and intent, and it’s added using:

git commit -s

When You Should Use DCO

1. 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

2. Your Project Accepts External Contributions

• Enforcing DCO ensures all contributions are traceable and legally clear

• It protects both the contributors and the maintainers

3. 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

4. Participating in Programs Like GSoC

• Google Summer of Code and similar programs often require DCO-compliant commits

When You Don’t Need DCO

1. 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

2. You’re in a Small Team and Trust Is High

• For tight-knit teams, you might rely on GitHub attribution or internal agreements instead

3. You're Not Planning to Accept External Contributions

• If your project is "read-only" for the public, you may skip DCO enforcement

Common Pitfalls to Avoid

How to Enforce DCO in Your Project

If you decide to use DCO, here’s how to enforce it:

1. Enable the DCO GitHub App
   Link: https://github.com/apps/dco

2. Add contribution instructions
   In CONTRIBUTING.md:

    ## DCO Notice
   
    All contributions must be signed off using:
   

   git commit -s

   
    This adds a `Signed-off-by:` line to your commit.
   

3. Reject unsigned commits in CI (optional)
   Some teams automate this with scripts or GitHub Actions.

Summary: DCO vs No DCO

Final Thoughts

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.