StackBlitz has developed WebContainers, a browser-based runtime that allows Node.js applications and operating system commands to run directly within a web browser tab. This innovative technology empowers developers to create immediate and engaging coding experiences, ranging from tutorials to comprehensive integrated development environments, all without requiring local installations or cloud-based virtual machines. Operating entirely on the client side, WebContainers provide exceptional user experiences characterized by zero latency, offline functionality, and increased security, as they remove the risks associated with executing code on servers. They support native Node.js toolchains, such as npm, pnpm, and yarn, and are compatible with leading modern frameworks. Furthermore, WebContainers offer seamless support for running WebAssembly (Wasm) right out of the box, enabling the adaptation of various programming languages and frameworks to operate within the browser environment. With these capabilities, developers can leverage the full potential of web technologies while maintaining flexibility and performance.