# Mailspring (open-source email and calendar app)

> Mailspring is a free, open-source email and calendar app for Windows, macOS and Linux. A beautiful, fast and fully open source mail client for Mac, Windows and Linux. It has 17,892 GitHub stars and is released under the GPL-3.0 license, and people use it instead of Microsoft Outlook.

Mailspring is a new version of Nylas Mail maintained by one of the original authors. It's faster, leaner, and shipping today! It replaces the JavaScript sync code in Nylas Mail with a new C++ sync engine based on Mailcore2. It uses roughly half the RAM and CPU of Nylas Mail and idles with almost zero "CPU Wakes", which translates to great battery life. It also has an entirely revamped composer and other great new features.

## Key facts

| Fact | Value |
|---|---|
| Repository | https://github.com/Foundry376/Mailspring |
| Platforms | Linux, macOS, Windows |
| Interface | desktop GUI |
| GitHub stars | 17,892 |
| License | GPL-3.0 (open source) |
| Replaces | Microsoft Outlook |
| Language | TypeScript |
| Website | https://getmailspring.com/ |
| Official | no |
| Category | Email & calendar |
| Latest release | 1.26.0 (Oct 2, 2026) |
| Last commit | Oct 7, 2026 |

## Install

Download a build for your system from the project's releases (https://github.com/Foundry376/Mailspring/releases) or website, or build it from source by following the README.

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