Thunderbird

About

Thunderbird is a desktop email program that began at Mozilla in 2003 and is now developed by MZLA Technologies, a subsidiary of the Mozilla Foundation that is funded largely by user donations. It manages several email accounts in one window over IMAP and POP3 and, since late 2025, supports Microsoft Exchange email natively; mail is stored locally, so it can be searched and read offline. A calendar, task list and address book are built in, as are a feed reader and a chat client for Matrix, XMPP and IRC. OpenPGP and S/MIME encryption work without plug-ins, and add-ons and themes extend it further. Users can pick a monthly release channel or the slower Extended Support Release. An Android app, based on the former K-9 Mail, is also available.

• Multiple accounts over IMAP, POP3 and Exchange
• Built-in calendar, tasks and address book
• OpenPGP and S/MIME encryption
• Feed reader and Matrix, XMPP and IRC chat
• Add-ons and themes