About OpenCallbook

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) weekly dump 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 tags, no third-party scripts beyond the Bootstrap and HTMX library files we serve from a CDN. Individual licensees' street addresses are suppressed in API responses, mirroring the FCC's own privacy posture for personal addresses. See Privacy for the full policy.

Open source

OpenCallbook is licensed under Apache 2.0.