Compare software

WhoisThisDomain vs OpenRDAP: catalog facts
WhoisThisDomain	OpenRDAP
Free Freeware from NirSoft, free to use and redistribute unmodified.	Free Free and open source under the MIT License.
Windows	Windows, Linux, Command line
Chooses the WHOIS server automatically by TLD Batch lookups and name-and-extension combinations	Supports domain, IP, autonomous system, nameserver, and entity queries. Outputs results as text or JSON, with WHOIS-style output for domain queries.
Only queries WHOIS servers on port 43, not web-based WHOIS Proxy authentication with a user name and password is not supported	Limitations not stated
Downloadable app	Downloadable app
Closed source	Open source
License: Freeware	License: MIT
No account needed	Not stated if an account is needed
Needs internet	Not stated if it works offline
Official website Full listing and sources Checked October 8, 2026	Official website Full listing and sources Checked October 6, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.