Emscripten

Emscripten 4.0.12 is out! 🚀

github.com/emscripten-c...

Includes a few minor API changes (see changelog), like using 64-bit indexes in statfs (needed for large filesystems)

Emscripten 4.0.11 is out! 🚀

github.com/emscripten-c...

Among other changes, this includes support for LLVM's source-based code coverage:

clang.llvm.org/docs/SourceB...

Emscripten 4.0.10 is out! 🚀

github.com/emscripten-c...

Includes LLVM library updates, better support for pkg-config, and lots of cleanups.

YouTube video by Alexander Guryanov Heroes of Might and Magic III in the Browser. Hard or not?

Nice and detailed video about porting games to the Web using Emscripten and WebAssembly.

Good summary of the things that port easily, and the things that don't (e.g. DirectX), and possible solutions.

www.youtube.com/watch?v=xMve...

Emscripten 4.0.9 is out! 🚀

github.com/emscripten-c...

Includes 64-bit integer handling fixes in several JS interop APIs (see changelog for more)

Emscripten 4.0.8 is out! 🚀

github.com/emscripten-c...

The wasm workers and audio worklets features no longer generate files on the side (.ww.js, .aw.js, respectively). Bundling the worker content in the main .js file improves code size and startup times.

Emscripten 4.0.7 is out! 🚀

github.com/emscripten-c...

Note that as the changelog mentions, there are some API changes to improve consistency and default code size. Most users should not be affected, but see the changelog for what might require a small modification.

Move JSPI to phase 4 by tlively · Pull Request #207 · WebAssembly/proposals We voted this to phase 4 at the April 8, 2025 meeting.

JSPI, the wasm JavaScript Promise Integration proposal, is now at phase 4:

github.com/WebAssembly/...

That means it is considered fully standardized.

JSPI lets wasm call JS APIs that return a Promise. The wasm awaits it.

It is still behind a flag in most browsers, but hopefully not for long!

Emscripten 4.0.6 is out! 🚀

github.com/emscripten-c...

Includes improved source maps support for easier debugging.

Emscripten 4.0.5 is out! 🚀

github.com/emscripten-c...

Mostly cleanups and fixes. Work continues on WasmFS. There is experimental support for wasm source imports,

github.com/tc39/proposa...

Emscripten 4.0.4 is out! 🚀

github.com/emscripten-c...

This release includes ports of SDL3 and Lua.

Jeopardy Clue Meaning perfectly acceptable, this word from "Simpsons" fame made it into Merriam-Webster in 2023

Thank you, Jeopardy!

This clue embiggened our hearts.

Emscripten 4.0.3 is out! 🥳

github.com/emscripten-c...

Mostly fixes this time.

I got Linux running in a PDF file using a RISC-V emulator.

PDFs support Javascript, so Emscripten is used to compile the TinyEMU emulator to asm.js, which runs in the PDF. It boots in about 30 seconds and emulates a riscv32 buildroot system.

linux.doompdf.dev/linux.pdf
github.com/ading2210/li...

Scaling multithreaded WebAssembly applications with mimalloc and WasmFS  |  Articles  |  web.dev WasmFS and the mimalloc feature in Emscripten can help a lot with allocation and I/O performance. This guide shows how these features can lead to speed improvements of 10 times or more in some cases.

📢 Scaling multithreaded #WebAssembly applications with mimalloc and WasmFS, by @kripken.com:
web.dev/articles/sca.... If you have a multithreaded #Wasm application that does lots of allocations or uses files, then you may benefit greatly by using WasmFS and/or mimalloc.

Emscripten 4.0.2 is out! 🥳

github.com/emscripten-c...

Wasm exception handling with exnref now uses LLVM rather than a translation from the old non-exnref code. This should only be noticeable as smaller and more efficient code, but it is a large change, please file issues if you see any problems.

Being used to the npm package hell it's kinda weird when an important software I use everyday (the Emscripten SDK) has a major version bump after 3 years from 3.x to 4.0 and nothing breaks :D

Congratulations @kripken.com (and the whole Emscripten team)!

Emscripten 4.0.1 is out! 🥳

github.com/emscripten-c...

Includes a few fixes after the recent 4.0.0 release.

Draft PR for Emscripten + wasm-bindgen support, with the goal of compiling C++ and Rust together into a single wasm file, with full library support for both languages:

github.com/emscripten-c...

YouTube video by Zombieschannel SFML Web Apps With Emscripten

Nice video that shows how to port SFML apps with Emscripten so they run on the Web:

www.youtube.com/watch?v=1kiw...

Emscripten 4.0.0 is out! 🚀

github.com/emscripten-c...

Many changes this time, including the major version number bump (mostly symbolic). Most importantly, several wasm features w/wide support are enabled by default for better code: bulk memory ops, nontrapping float to int, and js-bigint.

I made a Doom source port that runs within a PDF file.

PDFs support Javascript, so Emscripten is used to compile Doom to asm.js, which is then run within the PDF engine. Input/output is done by manipulating text input fields.

doompdf.pages.dev/doom.pdf

github.com/ading2210/do...

Updated settings.js to make it clear that MEMORY64 is no longer experimental. by dlemstra · Pull Request #23329 · emscripten-core/emscripten Emscripten: An LLVM-to-WebAssembly Compiler. Contribute to emscripten-core/emscripten development by creating an account on GitHub.

Your OSS pull request don't need to be major ones. Noticed a document that needed to be updated so I created this PR: github.com/emscripten-c.... It got merged within 15 minutes. I think this is my first PR for the @emscripten.org repository. I am using it for the #WASM version of @imagemagick.org

to use wasm64 in Emscripten, just compile and link with

emcc -sMEMORY64

(wasm64 and memory64 are effectively synonyms)

DOOM® CAPTCHA Prove you're human by playing DOOM

Doom CAPTCHA

a joke, but the game is compiled by Emscripten and fully functional!

doom-captcha.vercel.app

Unity's Emscripten export gets WebGPU support!

Fun fact: Unity's first (non-plugin) Web export, which used asm.js+Emscripten, was nicknamed "WebGL". Later it got Wasm support (through Emscripten updates), and lots of other changes, but this is the first time the WebGL part is changing.

Emscripten 3.1.74 is out! 🥳

github.com/emscripten-c...

Various filesystem improvements, as well as many internal simplifications (and code size wins) due to no longer supporting very old browsers.

Very cool, and uses Emscripten under the hood!

Please let us know what older browsers you run Emscripten builds on, as we are considering dropping support for some very old ones:

groups.google.com/g/emscripten...

(posting here or there is fine)

Very cool video about porting an SDL2 game to SDL3!

Emscripten part starts at 1:18:50

You can see the game running in a browser at 1:25:53