Compare software

Claws Mail vs The Bat!: catalog facts
Claws Mail	The Bat!
Free Free and open source under the GPL 3.0 or later.	Paid Commercial software from Ritlabs; prices are not listed on the product page.
Windows, macOS, Linux	Windows
Opens and searches enormous mail folders without stalling Plugins for PGP, spam filtering, RSS and calendars ship with it	Optional encryption of the local message base Blocks tracking pixels and malicious code in mail
Composes plain text by default; HTML mail sending is deliberately limited The interface is functional and looks like it was designed in 2004	Windows only Commercial license required
Downloadable app	Downloadable app
Open source	Closed source
License: GPL-3.0-or-later	License not stated
No account needed	No account needed
Works offline	Works offline
Official website Full listing and sources Checked September 21, 2026	Official website Full listing and sources Checked September 23, 2026

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