# 💌 Mailspring
**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](https://github.com/MailCore/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.
Mailspring's UI is open source (GPLv3) and written in TypeScript with [Electron](https://github.com/atom/electron) and [React](https://facebook.github.io/react/) - it's built on a plugin architecture and was designed to be easy to extend. Check out [CONTRIBUTING.md](https://github.com/Foundry376/Mailspring/blob/master/CONTRIBUTING.md) to get started!
Mailspring's sync engine is spawned by the Electron application and runs locally on your computer. [It is open source (GPLv3) and written in C++ and C.](https://github.com/Foundry376/Mailspring-Sync) For convenience, however, when you set up your development environment, Mailspring uses the latest version of the sync engine we've shipped for your platform so you don't need to pull sources or install its compile-time dependencies.
## Features
Mailspring comes packed with powerful features like Unified Inbox, Snooze, Send
Later, Mail Rules, Templates and more. Mailspring Pro, which you can unlock
with a monthly subscription, adds even more features for people who send a ton
of email: link tracking, read receipts, mailbox analytics, contact and company
profiles. **All of these features run in the client - Mailspring does not send
your email credentials to the cloud.** For a full list of features, check out
[getmailspring.com](https://getmailspring.com/).
## Download Mailspring
You can download compiled versions of Mailspring for Windows, Mac OS X, and
Linux (deb, rpm and snap) from
[https://getmailspring.com/download](https://getmailspring.com/download).
## Getting Help
You can find community-based help and discussion with other Mailspring users on our
[Discourse community](https://community.getmailspring.com/).
## Contributing
Mailspring is entirely open-source. Pull requests and contributions are
welcome! There are three ways to contribute: building a plugin, building a
theme, and submitting pull requests to the project itself. When you're getting
started, you may want to join our
[Discourse](https://community.getmailspring.com/) so you can ask questions and
learn from other people doing development.
[](CODE_OF_CONDUCT.md)
### Running Mailspring from Source
To install all dependencies and run Mailspring from its source code,
run the following commands from the root directory of the Mailspring repository:
```
export npm_config_arch=x64 # If you are on an M1 / Apple Silicon Mac
npm install
npm start
```
You can attach command line parameters by separating them using a double hyphen:
```
npm start -- --help
```
### Building Mailspring
To build Mailspring, you need to run the following command from the root directory
of the Mailspring repository:
```
npm run-script build
```
### Building A Plugin
Plugins lie at the heart of Mailspring and give it its powerful features.
Building your own plugins allows you to integrate the app with other tools,
experiment with new workflows, and more. Follow the [Getting Started
guide](https://Foundry376.github.io/Mailspring/) to write your first plugin in
five minutes.
- To create your own theme, check out the
[Mailspring-Theme-Starter](https://github.com/Foundry376/Mailspring-Theme-Starter).
- To create your own plugin, check out the
[Mailspring-Plugin-Starter](https://github.com/Foundry376/Mailspring-Plugin-Starter).
A plugin "store" like the Chrome Web Store is coming soon, and will make it
easy for other users to discover plugins you create. (Right now, users need to
"sideload" the plugins into the app by downloading them and copying them into
place.)
You can share and browse Mailspring Plugins, and discuss plugin development
with other developers, on our
[Discourse](https://community.getmailspring.com/).
### Building a Theme
The Mailspring user interface is styled using CSS, which means it's easy to
modify and extend. Mailspring comes stock with a few beautiful themes, and
there are many more which have been built by community developers. To start
creating a theme, [clone the theme starter](https://github.com/Foundry376/Mailspring-Theme-Starter)!
If you are updating an existing Nylas theme for Mailspring here is a
[step by step tutorial](https://community.getmailspring.com/t/updating-an-n1-nylas-mail-theme-for-mailspring/195).
Notice: as part of the update process you will probably need to [import mailspring base variables](https://github.com/Foundry376/Mailspring/issues/326#issuecomment-343757775).
You can share and browse Mailspring Themes, and discuss theme development with other developers, on our [Discourse](https://community.getmailspring.com/).
### Localizing / Translating
Mailspring (1.5.0 and above) supports localization. If you're a fluent speaker of
another language, we'd love your help improving translations. Check out the
[LOCALIZATION](https://github.com/Foundry376/Mailspring/blob/master/LOCALIZATION.md)
guide for more information. You can discuss localization and translation with
other developers on our [Discourse](https://community.getmailspring.com/).
### Contributing to Mailspring Core
Pull requests are always welcome - check out
[CONTRIBUTING](https://github.com/Foundry376/Mailspring/blob/master/CONTRIBUTING.md)
for more information about setting up the development environment, running
tests locally, and submitting pull requests.