WebKit2

WebKit2 is the multi-process architecture of the WebKit browser engine, introduced by Apple to separate browser user interface from web content in order to improve stability, security, and performance. It represents a redesign of the original, single-process WebKit and is the architecture most commonly associated with modern WebKit-based applications, including Safari.

In WebKit2, the browser runs across multiple processes rather than a single one. A UI process hosts the browser chrome, menus, and window management, while content rendering and JavaScript execution occur in separate content processes. This separation provides sandboxing and crash isolation: if a web page crashes, the UI process can continue running. Depending on the port and configuration, additional processes such as a network process may handle network requests and security policies. Communication between the processes uses an inter-process communication (IPC) layer.

WebKit2 is the framework used by Safari on macOS and iOS and has influenced how WebKit ports are structured. The older, single-process model of WebKit is often referred to as WebKit1, which is largely deprecated in modern deployments. The WebKit project maintains the WebKit2 architecture as its current multi-process approach, sometimes referred to by the shorthand WK2.

Overall, WebKit2 represents the shift toward process-per-tab or process-per-content models within WebKit, aiming to enhance stability and security while preserving the rendering and scripting capabilities of the WebKit engine.