The Ultralight Developer Hub

Welcome to the Ultralight developer hub. You'll find comprehensive guides and documentation to help you start working with Ultralight as quickly as possible, as well as support if you get stuck. Let's jump right in!

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What is Ultralight?

Ultralight is a lightweight, pure-GPU, HTML rendering engine for native apps. Our aim is to provide support for the majority of the HTML5/CSS/JavaScript spec while still being as lightweight (in binary size and memory usage) as possible.


The motivation for this project stemmed from the observation that Chromium and other layout engines have become suboptimal for use in desktop app UI due to a separate set of design goals (running untrusted code, favoring performance at the cost of memory, the need to support every web platform feature under the sun, etc.).

Low-Level Integration

Most native apps also need finer control over low-level platform functionality (such as file system, rendering, clipboard, etc.). Ultralight aims to not just be lightweight, but to offer native app developers much deeper integration with the underlying HTML engine.

Pure-GPU Renderer

Ultralight is also pure-GPU, meaning that all rendering (text, shadows, images, CSS transforms), is done via the GPU. The renderer emits abstract GPU commands (see the GPUDriver interface) which can then be handled by whichever graphics API you prefer (we provide stock implementations for D3D11, OpenGL, and Metal as of this writing).

Cross-Platform AppCore Runtime

On top of Ultralight, we've built an additional layer called AppCore that handles window creation, native event loops, native graphics API drivers, and more.

AppCore is intended to be used by those intending to build a standalone HTML-based desktop app and will eventually offer an API similar to Electron.


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