# Thunderbird (open-source email and calendar app)

> Thunderbird is a free, open-source email and calendar app for Windows, macOS and Linux. The official repository for the Thunderbird desktop email client. It has 184 GitHub stars and is released under the MPL-2.0 license, and people use it instead of Microsoft Outlook.

We also have documentation from this repository in a rendered version at Thunderbird Source Tree Documentation. In order to be able to build Thunderbird - you will need the Firefox repository as well as the Thunderbird repository (where this README lives). Check out our Getting Started documentation for instructions on how and where to get the source code.

## Key facts

| Fact | Value |
|---|---|
| Repository | https://github.com/thunderbird/thunderbird-desktop |
| Platforms | Linux, macOS, Windows |
| Interface | desktop GUI |
| GitHub stars | 184 |
| License | MPL-2.0 (open source) |
| Replaces | Microsoft Outlook |
| Language | JavaScript |
| Website | none listed |
| Official | yes (published by the project behind the app) |
| Category | Email & calendar |
| Latest release | none on GitHub |
| Last commit | Oct 7, 2026 |

## Install

Download a build for your system from the project's releases (https://github.com/thunderbird/thunderbird-desktop/releases) or website, or build it from source by following the README.

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