Apple WebKit2 adds baked-in split process support

It's not just multitasking and giving the iPhone user-customisable wallpaper that Apple's engineers have been working on; the company have announced that they've developed a new split-process API for WebKit – the underlying engine of Safari and other browsers – which they're calling WebKit2.  Like in Chrome, WebKit2 splits web content such as JavaScript, HTML and layout into a separate process from the browser UI; however, unlike Chrome, Apple have baked WebKit2 into the framework so that use is not limited to Apple's own browser.

That has repercussions for any browser based on WebKit, which currently includes Safari on Mac and Windows, various mobile browsers and not least Chrome itself (which uses WebKit as its rendering engine).

Right now there are binaries available for Mac and Windows, and we can probably expect to see test builds of browsers showing up over the next few months as developers get to grips with it.  The potential outcome is a more stable, crash-resilient and faster performing browser, which given so many people now live in the web, can't be a bad thing.

Hello everyone,

This is a heads-up that we will shortly start landing patches for a new WebKit framework that we at Apple have been working on for a while. We currently call this new framework "WebKit2".

WebKit2 is designed from the ground up to support a split process model, where the web content (JavaScript, HTML, layout, etc) lives in a separate process. This model is similar to what Google Chrome offers, with the major difference being that we have built the process split model directly into the framework, allowing other clients to use it.

Some high-level documentation is available at

Currently WebKit2 is available for Mac and Windows, and we would gladly accept patches to add more ports.

We're more than happy to answer any questions you might have, and we hope that this will be a topic of discussion at the WebKit Contributors Meeting.


Anders Carlsson and Sam Weinig.

[via Twitter]