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Open Source Thunderbird Alternatives

Discover 6 open source alternatives to Thunderbird. All free, community-driven, and actively maintained.

Thunderbird logo

What is Thunderbird?

A free, open-source email client and personal information manager for managing emails, calendars, and contacts.

Visit Thunderbird
Mailspring
Mailspring logo

Mailspring

:love_letter: A beautiful, fast and fully open source mail client for Mac, Windows and Linux.

thunderbird-android
thunderbird-android logo

thunderbird-android

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

stalwart
stalwart logo

stalwart

All-in-one Mail & Collaboration server. Secure, scalable and fluent in every protocol (IMAP, JMAP, SMTP, CalDAV, CardDAV, WebDAV).

Mail Server
roundcubemail
roundcubemail logo

roundcubemail

The Roundcube Webmail suite

Webmail Client
snappymail
snappymail logo

snappymail

Simple, modern & fast web-based email client

Web-based Email Client
cypht
cypht logo

cypht

Cypht: Lightweight Open Source webmail aggregator [PHP, JS]. Supports IMAP/SMTP, JMAP and EWS (Exchange Web Services)

Email