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muffet vs W3C Link Checker: catalog facts
muffet	W3C Link Checker
Free Free and open source.	Free Free to use on the W3C website.
Windows, macOS, Linux, Command line	Web
Fast concurrent crawling Fits easily into CI pipelines	Checks anchors as well as full URLs Recursive crawling with a configurable depth
Command line only, no graphical interface Focused on links rather than wider SEO or markup checks	Plain interface with a text-heavy report Works best when the pages already have valid markup
Downloadable app	Web application
Open source	Closed source
License not stated	License not stated
No account needed	No account needed
Not stated if it works offline	Needs internet
Official website Full listing and sources Checked September 23, 2026	Official website Full listing and sources Checked September 23, 2026

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