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eM Client vs Claws Mail: catalog facts
eM Client	Claws Mail
Freemium Free licence for personal, non-commercial use with up to two accounts; Personal from…	Free Free and open source under the GPL 3.0 or later.
Windows, macOS, Android, iOS	Windows, macOS, Linux
Handles Gmail, Microsoft 365, Outlook, Exchange and plain IMAP without plugins Email, calendar, tasks, contacts, notes and chat in one polished window	Opens and searches enormous mail folders without stalling Plugins for PGP, spam filtering, RSS and calendars ship with it
No Linux version The free licence is capped at two accounts and forbids any commercial use	Composes plain text by default; HTML mail sending is deliberately limited The interface is functional and looks like it was designed in 2004
Downloadable app	Downloadable app
Closed source	Open source
License not stated	License: GPL-3.0-or-later
Account needed	No account needed
Works offline	Works offline
Official website Full listing and sources Checked September 20, 2026	Official website Full listing and sources Checked September 21, 2026

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