Cheerp is an open-source, permissively licensed, enterprise-grade C/C++ compiler for Web applications. It allows to compile virtually any C/C++ code to WebAssembly and JavaScript.
Download the latest version of Cheerp: 
Main project link: https://leaningtech.com/cheerp/
This repository is the main reference for documentation, issue tracking, and release notes of Cheerp. The main component of Cheerp, i.e. the Cheerp compiler, can be found on Github: cheerp-compiler, while other repositories are at cheerp-musl, cheerp-utils and cheerp-libs
What is Cheerp
Cheerp is a C/C++ compiler to WebAssembly and JavaScript, based on and integrated into the LLVM/Clang infrastructure, and featuring numerous custom optimisation steps to maximise performance and minimise size of the compiled JavaScript/WebAssembly output. Thanks to this, Cheerp is the best performing, most optimised C++ to WebAssembly compiler available on the market.
Cheerp is used primarily to port existing C/C++ libraries and applications to HTML5, but can also be used to write high-performance Web applications and WebAssembly components from scratch. Using Cheerp, C/C++ code gets compiled into JavaScript/WebAssembly and optimised, with the right JavaScript interfaces being exposed, and can easily be integrated in a web application.
Cheerp is licensed under the "Apache 2.0 License with LLVM exceptions", i.e. the same license of upstream LLVM/Clang. This is a permissive license that allows virtually any use of the software.
What is unique about Cheerp?
Cheerp enables C/C++ code to be compiled to a combination of WebAssembly and JavaScript (or asm.js when targeting legacy browsers). Compared to alternative C/C++ compilers for web applications such as Emscripten, Cheerp:
- Generates more optimized (smaller) WebAssembly code, but can also compile to a JavaScript output with dynamic memory (garbage-collectible output), zero-overhead DOM manipulation and access to Web APIs and superior C++-JavaScript interoperability.
- Allows to compile a single code base into a combination of WebAssembly and JavaScript by (optionally) tagging portions of the code with
[[cheerp::genericjs]]and[[cheerp::wasm]].
Cheerp is free open-source software, actively developed and maintained by Leaning Technologies. Commercial support, feature fast tracking, sponsored developoment and consulting packages are available for Enterprise customers.
Get started
First time user? We recommend following the Getting started page, that will guide though these steps:
Or look at the sidebar to find lots of useful materials
Bugs and Questions
You can get in touch with us using Discord, or by filing a bug on our Issue tracker.