WebVM

WebVM runs full-fledged Linux environments directly in the browser by leveraging the CheerpX virtualization engine, which is based on WebAssembly and HTML5. This setup allows for the execution of unmodified x86 Linux binaries within a browser sandbox, eliminating the need for server-side infrastructure.

Technically, WebVM is composed of several key components: the CheerpX virtualization engine, a virtual storage backend, a networking layer, and an emulated graphical device. CheerpX includes an x86-to-WebAssembly Just-In-Time (JIT) compiler and a Linux syscall emulator, enabling the runtime execution of Linux x86 binaries. The virtual storage backend uses a streaming disk approach, dynamically loading disk blocks to support large file systems without preloading the entire filesystem, which is crucial for performance. The networking layer is integrated with Tailscale, providing encrypted and private bidirectional networking between the virtual machine and external networks. Additionally, WebVM utilizes xterm.js for a full-fledged terminal emulator, supporting complex terminal user interfaces (TUIs).

Operationally, WebVM is highly flexible, allowing users to customize and deploy their own versions via GitHub Pages or other hosting solutions. The project includes GitHub Actions workflows that automate the deployment process, making it straightforward to modify the Dockerfile and include custom packages or projects. However, self-hosting the CheerpX engine itself is not permitted without a commercial license.

From a performance perspective, WebVM can handle significant workloads, including graphical applications and desktop environments, thanks to the improved CheerpX engine. However, the performance may vary depending on the browser and system resources, particularly when running resource-intensive applications. The use of WebAssembly ensures compatibility across modern browsers, including mobile devices.