Alternatives to Claws Mail
A fast, keyboard-driven email client that loads a hundred thousand message folder without thinking about it. The listings below can replace it for an important use case. Each note says what changes if you switch.
The original
Claws Mail
A fast, keyboard-driven email client that loads a hundred thousand message folder without thinking about it.
Replacements
Listings that take over the same core job as Claws Mail.
Thunderbird
Mozilla’s desktop mail client, with calendar, contacts and a unified inbox, funded by donations rather than ads.
Thunderbird adds full HTML composing, a built-in calendar, tasks and an add-on ecosystem with OpenPGP, at the cost of a denser and heavier interface.
Betterbird
A Thunderbird fork that ships extra fixes and features, and can run side by side on the same profile.
Betterbird is a Thunderbird fork for Windows, macOS and Linux with extra fixes and a portable Windows build, run by a small volunteer project.
Evolution
GNOME's mail, calendar, contacts and tasks suite, and the usual answer for Exchange on Linux.
Evolution adds a real calendar, contacts, tasks and an Exchange plugin, but runs only on Linux and is heavier and slower to start.
KMail
KDE's email client with IMAP, filtering and OpenPGP support.
KMail integrates OpenPGP and S/MIME and shares calendar with Kontact, but is Linux only in practice and depends on the Akonadi storage service.
Geary
GNOME email client built around conversation threads.
Geary groups mail into conversations with fast full-text search, but is Linux only and deliberately minimal, with no encryption, rules engine or calendar.
Mailspring
A desktop mail client with a unified inbox, snooze and send later, whose paid tier adds read receipts.
Mailspring offers a modern Electron interface with snooze, send later and templates, but uses more resources than a native client and has read receipts on a paid tier.
NeoMutt
A fork of Mutt that gathered decades of scattered patches into one maintained terminal mail client.
NeoMutt moves to a terminal interface on macOS and Linux with Notmuch tags and compressed folders, but has no Windows build and requires writing a configuration file.
aerc
A terminal email client with vim-style keys, an embedded terminal for composing, and first-class support for git email workflows.
aerc is a terminal client with vim-style keys and a git patch workflow, supporting IMAP, Maildir, Notmuch and JMAP, but has no Windows build.
Also worth comparing
These listings name Claws Mail as their own alternative, so the relationship runs both ways.
Balsa
A lightweight GTK email client for the GNOME desktop.
Claws Mail is a fast, keyboard-driven client with PGP, spam and RSS plugins that handles very large folders, and also offers Windows installers.
Pegasus Mail
A long-running free desktop email client for Windows, maintained alongside the Mercury mail server.
Claws Mail is a free GPL client for Windows, macOS and Linux that handles huge folders quickly, with bundled PGP, spam and RSS plugins.
The Bat!
A Windows desktop email client that keeps mail locally, with on-disk encryption and end-to-end encryption.
Claws Mail is free and GPL-licensed, handles enormous mail folders quickly, ships PGP and spam plugins, and composes plain text by default.
Similar software
Related functionality, not a direct replacement.
isync
Fast IMAP to Maildir mirroring, usually invoked as mbsync.
OfflineIMAP
Synchronises IMAP accounts into local Maildir folders.
MailStore Home
Free Windows email archiver for IMAP, Exchange and PST files.
notmuch
A fast, tag-based email indexing and search system used from a terminal or text editor.
