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Subfinder vs Fierce: catalog facts
Subfinder	Fierce
Free The open-source software is available without a license fee. Hosting, hardware and…	Free Free and open source under the GPL-3.0 license.
Windows, macOS, Linux, Command line	Command line
Combines results from multiple discovery services.	Finds hostnames and related IP space through DNS reconnaissance Can traverse nearby IP addresses
Some data sources require API credentials or impose limits.	Intended for authorized testing Command-line interface only
Downloadable app	Downloadable app
Open source	Open source
License: MIT	License: GPL-3.0
Not stated if an account is needed	Not stated if an account is needed
Not stated if it works offline	Not stated if it works offline
Official website Full listing and sources Checked September 22, 2026	Official website Full listing and sources Checked October 8, 2026

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