Claws MailLinux
vs
ThunderbirdWindows
Claws Mail as a Linux alternative to Thunderbird
Updated
Our verdict
Claws Mail is a strong replacement for users who prioritize speed, keyboard control, and lightweight resource usage over graphical polish. It handles core IMAP/POP3 email, RSS, and Usenet well. However, it is not ideal for heavy calendar users or those needing built-in chat, as these require plugins or separate apps. If you want a fast, stable, text-centric workflow and do not mind configuring plugins, it is a solid choice. If you rely on Thunderbird’s integrated chat and rich calendar UI, you will feel a gap.
- License
- GPL-3.0-only
- Price
- Free
- Latest version
- 4.4.0 (March 9, 2026)
- Rating
- —
What works the same
- Free, open-source (GPL-3.0-only) email client
- Supports IMAP, POP3, and Usenet protocols
- Extensible via plugins for RSS and calendar
- Supports multiple accounts and folder structures
- Includes built-in spam filtering capabilities
What is different
- No built-in chat support (IRC/XMPP/Matrix) unlike Thunderbird
- Calendar functionality is plugin-based and less integrated
- Cannot compose HTML emails, only plain text
- Uses MH mailbox format instead of Thunderbird’s internal storage
- Interface is more keyboard-centric and less visually modern
Opening your Thunderbird files
Claws Mail supports importing emails from most other mail clients, including Thunderbird. You can typically import Thunderbird’s mbox files directly. For exporting, Claws Mail allows exporting messages to standard formats, making it easy to move data back to Thunderbird or other clients if needed.
Switching from Thunderbird to Claws Mail, step by step
- Install Claws Mail via your package manager or Flathub
- Export your Thunderbird mailboxes as mbox files
- In Claws Mail, use the import tool to select the mbox files
- Configure your IMAP/POP3 accounts with existing credentials
- Install required plugins for RSS or calendar if needed
- Test sending and receiving to ensure settings are correct
Key features of Claws Mail
- MH mailbox storage for fast access
- Keyboard‑centric operation with full shortcut support
- Plugin system for RSS, calendar, and extra protocols
- Multiple accounts and folder trees
- Built‑in spam filtering (SpamAssassin integration)
- Message threading and powerful search
- External editor support for composing plain‑text mail
- Import/export from most other mail clients
How to install Claws Mail on Linux
flatpak install flathub org.claws_mail.Claws-Mailsudo apt install claws-mailsudo apt install claws-mailsudo dnf install claws-mailsudo pacman -S claws-mailsudo zypper install claws-mailFrequently asked questions
Can I use Claws Mail for calendar events?
Yes, but you must install the calendar plugin. It is not as integrated or feature-rich as Thunderbird’s built-in calendar, so power users may prefer a dedicated calendar app.
Does Claws Mail support HTML email composition?
No. Claws Mail can read HTML emails via plugins, but it only composes plain-text messages. This is a design choice to keep the client lightweight and fast.
Is Claws Mail good for beginners?
It has a familiar interface, but its keyboard-centric design and plugin-based extras may have a steeper learning curve than Thunderbird for users who prefer click-heavy workflows.
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