⚡️ Native, high-performance, cross-platform desktop apps - built with Reason!
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bryphe API: Tick.interval (#214)
* Get simple tests green

* Formatting

* Add stopwatch example

* Move Clock -> Stopwatch

* Formatting

* Stopwatch example
Latest commit dc3f804 Jan 18, 2019


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Build native, high-performance, cross-platform desktop apps with reason!

Building & Installing

Install esy

esy is like npm for native code. If you don't have it already, install it by running:

npm install -g esy


  • esy install
  • esy build

For macOS users

If your build takes too much time then you can pre-install some libraries:

  • brew install cmake
  • brew install libpng ragel

For Linux users

Install the following packages with your package manager of choice:

  • cmake
  • ragel
For Ubuntu you may need these additional packages
  • libpng-dev
  • libbz2-dev
  • m4

For Windows Subsystem for Linux (WSL)

  • sudo apt install libpng-dev libbz2-dev m4 xorg-dev libglu1-mesa-dev


After building, you can run the example app by running:

  • esy x Examples

Check out our examples to see how they work!


Tests can be run with:

  • esy b dune runtest


Today, Electron is one of the most popular tools for building desktop apps - using an HTML, JS, CSS stack. However, it has a heavy footprint in terms of both RAM and CPU - essentially packing an entire browser into the app. Even with that tradeoff, it has a lot of great aspects - it's the quickest way to build a cross-platform app & it provides a great development experience - as can be testified by its usage in popular apps like VSCode, Discord, and Slack.

Revery is kind of like super-fast, native Electron - with a bundled React, Redux, and a fast build system - all ready to go!

Revery is built with reasonml, which is a javascript-like syntax on top of OCaml This means that the language is accessible to JS developers.

Your apps are compiled to native code with the Reason / OCaml toolchain - with instant startup and performance comparable to native C code. Revery also features GPU-accelerated rendering. The compiler itself is fast, too!

Revery is an experiment - can we provide a great developer experience and help teams be productive, without making sacrifices on performance?

Design Decisions

  • Consistent cross-platform behavior

A major value prop of Electron is that you can build for all platforms at once. You have great confidence as a developer that your app will look and work the same across different platforms. Revery is the same - aside from platform-specific behavior, if your app looks or behaves differently on another platform, that's a bug! As a consequence, Revery is like flutter in that it does not use native widgets. This means more work for us, but also that we have more predictable functionality cross-platform!

NOTE: If you're looking for something that does leverage native widgets, check out briskml. Another alternative is the cuite OCaml binding for Qt.

  • High performance

Performance should be at the forefront, and not a compromise - we need to develop and build benchmarks that help ensure top-notch performance and start-up time.

  • Type-safe, functional code

We might have some dirty mutable objects for performance - but our high-level API should be purely functional. You should be able to follow the React model of modelling your UI as a pure function of application state -> UI.


Check out revery-quick-start to get up and running with your own Revery app!

API Example

Here's a super simple Revery app, demonstrating the basic API surface:

open Revery;
open Revery.Core;
open Revery.UI;

/* The 'main' function for our app */
let init = app => {

  /* Create a window! */
  let win = App.createWindow(app, "test");

  /* Set up some styles */
  let textHeaderStyle = Style.make(~backgroundColor=Colors.black, ~color=Colors.white, ~fontFamily="Roboto-Regular.ttf", ~fontSize=24, ());

  /* Set up render function */
  let render = () => {
      <view style=(Style.make(~position=LayoutTypes.Absolute, ~bottom=10, ~top=10, ~left=10, ~right=10, ~backgroundColor=Colors.blue, ()))>
          <view style=(Style.make(~position=LayoutTypes.Absolute, ~bottom=0, ~width=10, ~height=10, ~backgroundColor=Colors.red, ())) />
          <image src="logo.png" style=(Style.make(~width=128, ~height=64, ())) />
          <text style=(textHeaderStyle)>"Hello World!"</text>
          <view style=(Style.make(~width=25, ~height=25, ~backgroundColor=Colors.green, ())) />

  /* Start the UI */
  UI.start(win, render);

/* Let's get this party started! */

Custom Components



It's early days for revery and we still have a lot of work ahead!

Some tentative work we need to do, in no particular order:

  • UI Infrastructure
    • Styles
    • State management / Redux-like layer
    • Focus Management
    • Input handling
    • Animations
    • Gestures
    • Transforms
    • Compositing / Container
    • zIndex / layers
  • UI Components
    • View
    • Image
    • Text
    • Input
    • Button
    • Slider
    • Checkbox
    • ScrollView
  • Platform support
    • Windows
    • OSX
    • Linux
    • Web (JS + Wasm)
  • Mobile support
    • Compilation to iOS
    • Compilation to Android
  • Developer Experience
    • Hot reloading
    • 'Time travel' debugging across states
    • Integrated debugger
    • Integrated performance profiler
  • Audio Support
    • Wav file playback
    • MP3 file playback
  • Example apps


Revery is provided under the MIT License.


We'd love your help, and welcome PRs and contributions. Join us on Discord!

Some ideas for getting started:

Special Thanks

revery would not be possible without a bunch of cool tech:

revery was inspired by some awesome projects: