stackblitz/webcontainer-core
Webcontainer Core
WebContainer is a browser-based runtime environment designed to execute server-side code, operating system commands, and full-stack development toolchains directly within a web tab. It provides the infrastructure for cloud IDEs and zero-install development workflows by simulating a runtime that eliminates the need for local installations or remote virtual machines.
The system leverages WebAssembly to map system calls and implements a virtual POSIX-compliant filesystem and network interception layer. This allows the runtime to spawn command-line processes, execute shell commands, and route internal server requests to browser-accessible URLs for live web application previewing.
The platform also includes capabilities for managing virtual filesystem operations, monitoring file changes, and integrating with private package registries via single sign-on and identity verification. It can be deployed on-premises or within private cloud infrastructure to keep execution behind corporate firewalls.
Features
- Browser-Based Execution Environments - Provides a full-stack, browser-based execution environment that simulates an operating system to run server-side code.
- Browser-Based Runtimes - Provides a full-stack server runtime that executes directly within a web browser environment.
- Virtual Filesystems - Implements a POSIX-compliant virtual filesystem that allows browser-based applications to manage project files and monitor changes.
- Virtualized Filesystem Layers - Simulates a POSIX-compliant file system in memory to allow server-side tools to read and write files.
- Client-Side Development Environments - Provides the infrastructure to execute build toolchains and servers in a browser tab, eliminating the need for remote virtual machines.
- Cloud IDEs - Provides the underlying runtime for online code editors that manage virtual filesystems and execute toolchains.
- Browser-Based Development Environments - Provides full stack coding environments that run entirely in the browser to remove the need for local installations.
- Shell Command Execution - Enables the execution of system processes and shell commands within the browser environment.
- Browser-Based Shell Execution - Implements a system for spawning command-line processes and executing shell commands directly within the browser.
- Zero-Install Workflows - Implements zero-install workflows by providing an immediate, operational development environment directly in the browser.
- In-Browser Process Management - Manages the lifecycle of multiple concurrent command-line processes and their standard input and output streams.
- Browser-Based System Call Interceptors - Maps standard operating system calls to WebAssembly functions to execute binary toolchains within the browser sandbox.
- Node.js Sandbox Runtimes - Initializes a full Node.js sandbox runtime using WebAssembly and a virtualized filesystem inside the browser.
- Toolchain Execution - Runs compilers and bundlers directly in the browser by leveraging a virtualized environment.
- Browser-side Execution Environments - Provides a browser-side execution environment to run server-side code and command-line tools without a remote backend.
- Virtual File Systems - Provides a virtual file system to create, read, write, and delete files or mount data sets.
- Local File Operations - Performs standard filesystem operations such as reading, writing, renaming, and deleting files and folders.
- Filesystem Change Monitors - Watches for modifications to specific files or directories to trigger automatic updates or reactions.
- Web Application Previews - Captures the URL of a running server and renders the output in a frame for live viewing.
- Registry Connections - Enables connecting to and installing dependencies from private corporate package registries within the browser runtime.
- Browser-Based Toolchain Execution - Runs build tools and module bundlers directly in the browser to enable interactive coding experiences.
- Process Execution - Provides utilities for spawning and managing the lifecycle of command-line processes within the virtualized runtime.
- Filesystem Mounting - Loads a directory tree or binary snapshot into the runtime to provide the initial set of project files.
- Live Preview Refreshing - Reloads preview frames via messaging or source resets to reflect recent changes in the browser environment.
- Network Request Interception - Captures requests from internal servers and routes them to a browser-accessible URL for live previewing.
