# Alternatives to Thunderbird

Mozilla's open source desktop mail.

Thunderbird ranks #12 of 22 in Email clients, with an Alt Score of 76. It is licensed under MPL-2.0, donationware and available on Windows, macOS and Linux. 10 of 11 checklist rows are verified against a public source.

Source: https://altcatalog.com/alternatives/thunderbird/
Category: Email clients

## Overview

- **Who it's for**: People who manage one or more email accounts and want a free, open-source, privacy-respecting desktop client instead of a commercial webmail service—especially users who value data ownership, customization, and cross-platform (Windows/macOS/Linux) support.
- **What you get**: A unified inbox for multiple email accounts alongside built-in calendar and contacts management. Messages can be organized with tags, filters, and folders, and the interface is customizable and extensible through add-ons. Thunderbird is developed as open-source software by Mozilla and does not collect personal data or sell ads based on your inbox contents.
- **How it works**: You download and install Thunderbird, then add your existing email account(s) via their login credentials or server settings. From there you read, organize, and send mail, manage your calendar and contacts, and tailor the interface and behavior through settings and add-ons.

## Profile

- **License**: MPL-2.0 (verified 2026-07-12)
- **Pricing model**: Donationware (verified 2026-07-12)
- **Starts at**: ?
- **Platforms**: Windows, macOS, Linux
- **Status**: active (verified 2026-07-12)

## Ranked alternatives

| # | App | Alt Score | Licence | Platforms |
|---|-----|-----------|---------|-----------|
| 1 | [eM Client](https://altcatalog.com/alternatives/em-client.md) | 96 | Proprietary | Windows, macOS, iOS, Android |
| 2 | [BlueMail](https://altcatalog.com/alternatives/bluemail.md) | 92 | Proprietary | Windows, macOS, Linux, iOS |
| 3 | [Canary Mail](https://altcatalog.com/alternatives/canary-mail.md) | 92 | Proprietary | Windows, macOS, iOS, Android |
| 4 | [The Bat!](https://altcatalog.com/alternatives/the-bat.md) | 92 | Proprietary | Windows |
| 5 | [Apple Mail](https://altcatalog.com/alternatives/apple-mail.md) | 87 | Proprietary | macOS, iOS |
| 6 | [FairEmail](https://altcatalog.com/alternatives/fairemail.md) | 87 | GPL-3.0 | Android |
| 7 | [Mailbird](https://altcatalog.com/alternatives/mailbird.md) | 87 | Proprietary | Windows, macOS |
| 8 | [Evolution](https://altcatalog.com/alternatives/evolution.md) | 84 | LGPL-2.1 | Linux |
| 9 | [Mailspring](https://altcatalog.com/alternatives/mailspring.md) | 84 | GPL-3.0 | Windows, macOS, Linux |
| 10 | [Missive](https://altcatalog.com/alternatives/missive.md) | 84 | Proprietary | Web, Windows, macOS, iOS |
| 11 | [Outlook](https://altcatalog.com/alternatives/outlook.md) | 84 | Proprietary | Windows, macOS, iOS, Android |
| 12 | [Spark](https://altcatalog.com/alternatives/spark.md) | 71 | Proprietary | Windows, macOS, iOS, Android |
| 13 | [NeoMutt](https://altcatalog.com/alternatives/neomutt.md) | 68 | GPL-2.0 | Linux, macOS |
| 14 | [Shortwave](https://altcatalog.com/alternatives/shortwave.md) | 68 | Proprietary | Web, macOS, Windows, iOS |
| 15 | [Postbox](https://altcatalog.com/alternatives/postbox.md) | 63 | Proprietary | macOS, Windows |
| 16 | [Mimestream](https://altcatalog.com/alternatives/mimestream.md) | 60 | Proprietary | macOS |
| 17 | [Aqua Mail](https://altcatalog.com/alternatives/aqua-mail.md) | 55 | Proprietary | Android |
| 18 | [Superhuman](https://altcatalog.com/alternatives/superhuman.md) | 55 | Proprietary | Windows, macOS, iOS, Android |
| 19 | [Geary](https://altcatalog.com/alternatives/geary.md) | 50 | LGPL-2.1-or-later | Linux |
| 20 | [K-9 Mail](https://altcatalog.com/alternatives/k-9-mail.md) | 47 | Apache-2.0 | Android |
| 21 | [aerc](https://altcatalog.com/alternatives/aerc.md) | 42 | MIT | Linux, macOS |

Alt Score = Verified coverage (90%) + Visibility (10%). See https://altcatalog.com/how-alt-score-works/

## Feature comparison

Legend: Yes / No / Partial / ? (not verified).

| Email clients checklist | Thunderbird | eM Client | BlueMail | Canary Mail | The Bat! | Apple Mail |
|---|---|---|---|---|---|---|
| Pricing model | Donationware | Freemium | Freemium | Freemium | One-time | Free |
| Starts at | ? | €39.95/year | ? | $3/month | €47.95 one-time (Home Edition) | ? |
| License | MPL-2.0 | Proprietary | Proprietary | Proprietary | Proprietary | Proprietary |
| Platforms | Windows, macOS, Linux | Windows, macOS, iOS, Android | Windows, macOS, Linux, iOS, Android, Web | Windows, macOS, iOS, Android | Windows | macOS, iOS |
| Protocols (IMAP / POP3 / JMAP / Exchange) | Yes | Yes | Yes | Partial | Yes | Yes |
| Unified inbox | Yes | Yes | Yes | Yes | Yes | Yes |
| Snooze & send later | No | Yes | Yes | Yes | Partial | Yes |
| Tracking pixel blocking | ? | Yes | Yes | Yes | Yes | Yes |
| PGP / encryption support | Yes | Yes | Yes | Yes | Yes | Partial |
| Conversation view | Partial | Yes | Yes | Yes | Yes | Yes |
| Offline mode | Yes | Yes | Yes | Yes | Yes | Yes |
| Rules & filters (local) | Yes | Yes | Partial | Yes | Yes | Yes |
| Calendar integrated | Yes | Yes | Yes | Yes | Yes | Partial |
| Multiple identities/aliases | Yes | Yes | Yes | Yes | Yes | Yes |
| Keyboard-first shortcuts | Partial | Partial | Partial | Partial | Partial | Partial |

## Sources

Sources for Thunderbird. Each alternative is sourced on its own page.

- **Platforms**: Windows, macOS, Linux — <https://www.thunderbird.net/en-US/download/> (verified 2026-07-12)
  - Quote: “Meet the powerful email, calendar, and contacts app for Windows, Linux, and macOS.”
- **License**: MPL-2.0 — <https://github.com/thunderbird/thunderbird-desktop/blob/main/mail/moz.build> (verified 2026-07-12)
  - Quote: “This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.”
- **Pricing model**: Donationware — <https://www.thunderbird.net/en-US/donate/> (verified 2026-07-12)
  - Quote: “Currently, nearly 100% of Thunderbird’s operating revenue comes from the generous gifts of Thunderbird users.”
- **Status**: active — <https://blog.thunderbird.net/2025/11/thunderbird-adds-native-microsoft-exchange-email-support/> (verified 2026-07-12)
  - Quote: “Thunderbird’s latest monthly Release version 145, now officially supports native access via the Exchange Web Services (EWS) protocol.”
- **Protocols (IMAP / POP3 / JMAP / Exchange)**: Yes — <https://blog.thunderbird.net/2025/11/thunderbird-adds-native-microsoft-exchange-email-support/> (verified 2026-07-12)
  - Quote: “Thunderbird users in Exchange hosted environments often relied on IMAP/POP protocols or third-party extensions. With full native Exchange support for email, Thunderbird now works more seamlessly in Ex”
- **Unified inbox**: Yes — <https://www.thunderbird.net/en-US/features/> (verified 2026-07-12)
  - Quote: “Manage all accounts separately or in a unified inbox.”
- **Snooze & send later**: No — <https://blog.thunderbird.net/2024/09/maximize-your-day-extend-your-productivity-with-add-ons/> (verified 2026-07-12)
  - Quote: “This add-on adds true send later functionality to Thunderbird, so you decide when that message gets sent, whether it’s one time or regularly.”
- **PGP / encryption support**: Yes — <https://blog.thunderbird.net/2020/09/openpgp-in-thunderbird-78/> (verified 2026-07-12)
  - Quote: “it is no longer needed with Thunderbird version 78.2.1 because it enables a new built-in OpenPGP feature.”
- **Conversation view**: Partial — <https://blog.thunderbird.net/2025/10/video-conversation-view/> (verified 2026-07-12)
  - Quote: “in contrast to the current threaded view, you have all the messages in a thread”
- **Offline mode**: Yes — <https://blog.thunderbird.net/2024/09/why-use-a-mail-client-vs-webmail/> (verified 2026-07-12)
  - Quote: “Email clients store your emails locally on your device, so you can access and compose emails even without an internet connection.”
- **Rules & filters (local)**: Yes — <https://blog.thunderbird.net/2024/11/maximize-your-day-make-important-messages-stand-out/> (verified 2026-07-12)
  - Quote: “A property is a message element or characteristic such as “Subject” or “From””
- **Calendar integrated**: Yes — <https://www.thunderbird.net/en-US/features/> (verified 2026-07-12)
  - Quote: “Access all your messages, calendars, and contacts in one fast app.”
- **Multiple identities/aliases**: Yes — <https://webextension-api.thunderbird.net/en/mv3/identities.html> (verified 2026-07-12)
  - Quote: “The identities API allows to manage the user’s identities (each account can have multiple identities).”
- **Keyboard-first shortcuts**: Partial — <https://blog.thunderbird.net/2025/08/maximize-your-day-getting-things-done-with-thunderbird/> (verified 2026-07-12)
  - Quote: “Once a message comes in, click the number for the tag you want. If you accidentally press the wrong number, don’t worry! Just press ‘0’ to clear whatever label you applied.”

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Ranked by verified data, never by who paid. https://altcatalog.com/trust/