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emscripten-core/emscripten

📈 Trending★ 27,370C++Audience · developerComplexity · 4/5ActiveLicenseSetup · hard

TLDR

Compiler that translates C and C++ code into WebAssembly so programs run directly in web browsers at near-native speed.

Mindmap

mindmap
  root((Emscripten))
    What it does
      Compiles C/C++ to WebAssembly
      Runs in browsers
      Ports desktop apps to web
    Tech stack
      LLVM compiler
      WebAssembly output
      C and C++ input
    Use cases
      Game porting
      Physics simulations
      Image processing
    Compatibility
      OpenGL graphics
      SDL2 input
      Node.js support

Things people build with this

USE CASE 1

Port an existing C++ game to run in a web browser without rewriting the code.

USE CASE 2

Convert a physics simulation or scientific tool written in C into a web-based application.

USE CASE 3

Deploy an image processing library to the web so users can process files directly in their browser.

USE CASE 4

Make a desktop multimedia application accessible online without requiring installation.

Tech stack

C++LLVMWebAssemblyOpenGLSDL2

Getting it running

Difficulty · hard Time to first run · 1day+

Building LLVM-based compiler from source requires significant compilation time and multiple system dependencies (C++ toolchain, LLVM libraries, WebAssembly SDK).

Open source under permissive licenses; use freely for any purpose including commercial applications.

In plain English

Emscripten is a compiler tool that takes programs written in C or C++ and translates them into WebAssembly so they can run in a web browser. WebAssembly (often shortened to "wasm") is a format that allows code originally written for desktop computers to run on the web at near-native speed, meaning programs that traditionally only worked as installed desktop applications can now work directly in a browser tab. The way it works: Emscripten uses a compiler infrastructure called LLVM to transform C/C++ source code into WebAssembly output. That output can then run in any modern web browser, in Node.js (a server-side JavaScript environment), or in standalone WebAssembly runtimes. It also provides compatibility layers for popular graphics and input APIs like OpenGL and SDL2, which are widely used in game development and multimedia applications. This makes it possible to port complex native applications, the README mentions examples like the Unity game engine and Google Earth, to run on the web without rewriting them. You would use Emscripten when you have an existing C or C++ program, such as a game, a physics simulation, an image processing library, or any performance-heavy tool, and you want it to run in a browser without requiring users to download anything. It also supports integration with other languages that target LLVM, such as Rust. Emscripten is open source under permissive licenses.

Copy-paste prompts

Prompt 1
How do I use Emscripten to compile my C++ game so it runs in a web browser?
Prompt 2
Show me an example of porting a C library with OpenGL graphics using Emscripten.
Prompt 3
What are the performance differences between native C++ and C++ compiled to WebAssembly with Emscripten?
Prompt 4
How do I integrate Emscripten into my build pipeline to automatically generate WebAssembly from C++ source?
Prompt 5
Can I use Emscripten to compile Rust code to WebAssembly, and how does it compare to other Rust-to-wasm tools?
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Generated 2026-05-18 · Model: sonnet-4-6 · Verify against the repo before relying on details.