# WebAssembly/binaryen

Optimizer and compiler/toolchain library for WebAssembly

Repository: https://github.com/WebAssembly/binaryen
Canonical: https://ross.abutalabs.com/products/binaryen
Language: WebAssembly
License: Apache-2.0
License Family: permissive
Topics: emscripten, webassembly, compilers, c-plus-plus, hacktoberfest
Last push: 2026-08-26T23:28:59+00:00

## Health v2 (maintenance only)
Score: 94/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 85, longevity 100
- inputs: {"age_days": 3961, "days_push": 7, "days_rel": 21, "gap_med": 49.0, "n_releases_24m": 15}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 8612, forks 881 (observed 2026-08-28T04:10:23.799070+00:00)

## What it is
Binaryen is a compiler and toolchain infrastructure library for WebAssembly, written in C++, with a simple C API and JavaScript bindings. It parses, emits, interprets, and optimizes WebAssembly, and its wasm-opt optimizer is used by toolchains like Emscripten, wasm-pack, and Kotlin/Wasm.

## Use cases
- optimize and minify webassembly binaries for size and speed
- compile a custom language to webassembly using a backend library
- convert webassembly to javascript with wasm2js
- parse, transform, and re-emit wasm modules in a build pipeline
- interpret webassembly modules for testing

## When to choose
- you need wasm-specific optimizations beyond what general compilers provide
- you are building a compiler targeting webassembly and want a reusable backend
- you want to shrink or speed up wasm output from Emscripten, Rust, Kotlin, or Dart toolchains

## When to avoid
- you need a general-purpose optimizer for native machine code rather than wasm
- you only need to run wasm, not compile or optimize it
- you want a high-level language runtime rather than a compiler infrastructure library

## Facets
- artifact type: library
- maturity: stable
- function: compiler, build-tool, developer-tools
- domain: compilers, web-development, developer-tools
- platform: cross-platform, cpp, cli
- tags: webassembly, wasm-opt, optimizer, compiler-backend, toolchain, emscripten, nodejs

## Member repositories
- WebAssembly/binaryen (main) score 94

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:10:23.799070+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T17:25:53.562112+00:00, confidence not recorded.
  - readme: https://github.com/WebAssembly/binaryen (fetched 2026-08-28T04:10:23.799070+00:00, sha dbe1d0ad0436)
- Data as of 2026-08-30T08:39:29.467469+00:00.