OpenCallbook is a free, fast lookup service for FCC-licensed call signs across Amateur Radio and GMRS. We pull the FCC's official Universal Licensing System (ULS) public release every Sunday and serve it through a clean web interface and a documented public REST API.
Why it exists
Most call sign lookup services cover amateur radio only, hide features behind paywalls, or don't expose a developer-friendly API. OpenCallbook covers both amateur and GMRS, is free, and ships with first-class OpenAPI 3.1 docs so anyone can build on top of it.
Where the data comes from
The FCC publishes the ULS public release weekly, in the public domain.
OpenCallbook ingests l_amat.zip and l_gmrs.zip from
the FCC's official downloads page.
We don't scrape any other site.
Privacy
We don't track you. No analytics, no third-party scripts. License data is shown exactly as the FCC publishes it — including addresses, which are part of the public ULS file. Licensees who request P.O. Box redaction at the FCC will appear with their P.O. Box, not their home address. See the privacy policy for details.
Open source
OpenCallbook is licensed under Apache 2.0.