Browser Layout Engines

Because the Web platform is a set of open standards, there are multiple browser engine implementations.

Gecko is Mozilla's browser engine, used in its Firefox web browser, the Thunderbird email client, and the SeaMonkey internet suite. Goanna is a fork of Gecko used in the Pale Moon browser.

Apple created the WebKit engine for its Safari browser by forking the KHTML engine of the KDE project.

Google originally used WebKit for its Chrome browser but eventually forked it to create the Blink engine. All Chromium-based browsers use Blink, as do applications built with CEF, Electron, or any other framework that embeds Chromium.

Although Apple permits third-party browsers as alternatives to Safari on iOS devices, all browsers distributed through its App Store must use WebKit as their engine. For example, Opera Mini for iOS uses WebKit, whereas all other Opera variants use Blink. (Opera formerly used its own proprietary Presto engine.)

Microsoft maintains its own proprietary EdgeHTML engine, which is the successor of its Trident engine. However, EdgeHTML is now only used for Universal Windows Platform apps, as the Edge browser has been remade with the Blink engine.