Project Positron

Along with several colleagues, I recently started working on Project Positron, an effort to build an Electron-compatible runtime on top of the Mozilla technology stack (Gecko and SpiderMonkey). Mozilla has long supported building applications on its stack, but the process is complex and cumbersome. Electron development, by comparison, is a dream. We aim to bring the same ease-of-use to Mozilla.

Positron development is proceeding along two tracks. In the SpiderNode repository, we’re working our way up from Node, shimming the V8 API so we can run Node on top of SpiderMonkey. Ehsan Akhgari details that effort in his Project SpiderNode post.

In the Positron repository, we’re working our way down from Electron, importing Electron (and Node) core modules, stubbing or implementing their native bindings, and making the minimal necessary changes (like basing the <webview> element on <iframe mozbrowser>) so we can run Electron apps on top of Gecko. Eventually we aim to join these tracks, even though we aren’t yet sure exactly where the last spike will be located.

It’s early days. As Ehsan noted, SpiderNode doesn’t yet link the Node executable successfully, since we haven’t shimmed all the V8 APIs it accesses. Meanwhile, Positron supports only a tiny subset of the Electron and Node APIs.

Nevertheless, we reached a milestone today: the tip of the Positron trunk now runs the Electron Quick Start app described in the Electron tutorial. That means it can open a BrowserWindow, hook up a DevTools window to it (with Firefox DevTools integration contributed by jryans), and handle basic application lifecycle events. We’ve imported that app into the Positron repository as our “hello world” example.

Clone and build Positron to see it in action!



Myk Melez

Myk is a Principal Software Architect and in-house entrepreneur at Mozilla. A Mozillian since 1999, he's contributed to the Web App Developer Initiative, PluotSorbet, Open Web Apps, Firefox OS Simulator, Jetpack, Raindrop, Snowl, Personas, Firefox, Thunderbird, and Bugzilla. He's just a cook. He's all out of bubblegum.


2 thoughts on “Project Positron

  1. That sounds quite… energetic. How much lead shielding will I need? 🙂

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