Compare software

Zopfli vs crabz: catalog facts
Zopfli	crabz
Free Free and open source from Google.	Free Free and open source, dual-licensed under MIT and the Unlicense.
Command line	macOS, Linux, Command line
Smaller output than standard gzip at its highest level Output readable by any gzip, zlib or deflate decoder	Multi-threaded compression in the style of pigz Supports Gzip, Zlib, BGZF, Mgzip, raw Deflate and Snap
Much slower than ordinary compressors Compresses only; decompression uses standard tools	Described by its author as a proof of concept Handles single streams, not archive formats like ZIP or 7z
Downloadable app	Downloadable app
Open source	Open source
License not stated	License: MIT OR Unlicense
No account needed	No account needed
Works offline	Works offline
Official website Full listing and sources Checked October 2, 2026	Official website Full listing and sources Checked September 23, 2026

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