What is who-dat?

who-dat is a free and open-source domain lookup service that queries RDAP first and falls back to WHOIS, returning normalized JSON for any domain. It discovers the correct RDAP server per TLD via IANA bootstrap, parses nested jCard contact data, and provides a single consistent API response. The service includes a lightweight web interface built with Alpine.js, API documentation, health check endpoint, in-memory caching, optional rate limiting, and optional API key authentication. It can be self-hosted via Docker (lissy93/who-dat), pre-built binaries for multiple architectures, 1-click Vercel deployment, or built from source with Go. The public demo runs at who-dat.as93.net.

Should you self-host who-dat?

who-dat scores 53/100 on selfhost.directory (how scoring works) and ranks #19 of 41 in DNS. It has 323 GitHub stars.

There was no stable release in the past 12 months, so check the repository's recent activity before you rely on it.

Setup is easy: most people get it running in one sitting. An official Docker image is available. It is MIT-licensed and written mostly in Go.

Its closest alternative on selfhost.directory is Pi-hole (87/100, 61 522 stars). It scores higher overall, so compare the two before you pick. See who-dat vs Pi-hole side by side.