Freedom251 › Open Source License Compliance Software
ClearlyDefined
What ClearlyDefined is
ClearlyDefined is an open source project that gathers and improves licensing, security, and other information about free and open source software. It links harvested and contributor-curated data to source code or packages. Definitions can include declared and discovered licenses, attribution parties, file details, and source information; harvesting can use tools such as ScanCode and FOSSology. Users can browse the data on the web or connect systems through a REST API. Documented providers include GitHub, Maven Central, NpmJS, NuGet, GitLab, and crates.io. Contributors submit curation changes through the API, where they ultimately appear as pull requests in the configured curation repository. The project assigns components unique coordinates and allows links between them, but does not attempt to resolve component identity. Its source code is licensed under MIT, and its data is distributed under CC0. The Open Source Initiative manages the project, which welcomes participation through GitHub and Discord. All data is available for everyone to see and use; the ClearlyDefined plan costs nothing. Production API POST requests to definitions, curations, and notices are limited to 250 per minute; other endpoints allow up to 2,000 requests per minute.
Who it suits
ClearlyDefined suits people and teams that need licensing and related information about free and open source components. It offers both a web interface and a REST API, with a route for contributors to propose curated changes.
What it does well
- Web interface and REST API provide access to data.
- Definitions include license and attribution details.
- Harvesting can use ScanCode and FOSSology.
- Source code uses the MIT license; data uses CC0.
- Data is available for everyone to see and use.
What to know first
- Does not attempt to resolve component identity.
- POST requests to specified production endpoints are limited to 250 per minute.
Plans
| Plan | Billed and limits | Price |
|---|---|---|
| ClearlyDefined | All data is available for everyone to see and use | Free |
As clearlydefined.io lists them, read 4 Oct 2026. The maker's own page has the final word.
Verdict
ClearlyDefined offers public component data, curation, and API access under open source terms. Its stated scope excludes solving component identity, and API users should account for endpoint-specific request limits.
Facts from ClearlyDefined's own pages
- Access
- Users can browse the data in a web UI or connect their systems through the REST API. · docs.clearlydefined.io, 4 Oct 2026
- API limits
- On the production API, POST requests to definitions, curations, and notices are limited to 250 per minute, while other endpoints allow up to 2,000 requests per minute. · docs.clearlydefined.io, 4 Oct 2026
- Community support
- The project invites participation through its GitHub community and Discord forum. · docs.clearlydefined.io, 4 Oct 2026
- Curation
- Contributors can submit curation changes through the API, where they ultimately surface as pull requests in the configured curation repository. · docs.clearlydefined.io, 4 Oct 2026
- Data
- The project manages harvested data, curated data, and a merge of both, relating data to source code or packages. · docs.clearlydefined.io, 4 Oct 2026
- Governance
- The FAQ says ClearlyDefined is managed by the Open Source Initiative. · docs.clearlydefined.io, 4 Oct 2026
- Harvesting
- ClearlyDefined can harvest component data using tools such as ScanCode and FOSSology. · docs.clearlydefined.io, 4 Oct 2026
- Integrations
- The documented provider list includes GitHub, Maven Central, NpmJS, NuGet, GitLab, crates.io, and other package providers. · docs.clearlydefined.io, 4 Oct 2026
- License information
- Definitions can include declared and discovered licenses, attribution parties, file details, and source information. · docs.clearlydefined.io, 4 Oct 2026
- Open source terms
- The source code is licensed under MIT and the data is distributed under CC0. · docs.clearlydefined.io, 4 Oct 2026
- Purpose
- ClearlyDefined is an open source project that crowdsources the gathering, curation, and upstreaming of licensing, security, and other data about free and open source projects. · docs.clearlydefined.io, 4 Oct 2026
- Scope limit
- ClearlyDefined assigns unique coordinates to components and allows links between them, but says it is not attempting to solve the identity problem. · docs.clearlydefined.io, 4 Oct 2026