WebAssembly Tooling

WebAssembly is real production infrastructure in 2026 — used inside Cloudflare Workers, Shopify Functions, Fastly Compute, Figma, Photoshop Web, and most modern image / crypto libs.

Build TS / JS to WASM

• Javy (Shopify) — compiles JS to WASM via QuickJS; used for Shopify Functions.
• AssemblyScript — TS-like syntax that compiles to WASM; not actually TS but close.
• Porffor — JS-to-WASM AOT compiler; experimental, watch this space.

Build Rust to WASM

• ★ wasm-pack + wasm-bindgen — the standard pipeline.
• wit-bindgen — WIT (WebAssembly Interface Types) → bindings; for the Component Model.
• trunk — Rust web app builder; handles WASM bundling.

Build Go / C / C++ to WASM

• TinyGo — Go subset that compiles to small WASM binaries.
• Emscripten — C / C++ → WASM; mature.
• GCC --target=wasm32 — direct.

Run WASM outside the browser

• ★ Wasmtime — Bytecode Alliance reference runtime; fast, mature; used by Fastly Compute.
• Wasmer — competitor; package-manager-style WAPM.
• WasmEdge — CNCF runtime focused on edge / cloud.
• Spin (Fermyon) — opinionated WASM-microservice framework.
• Wazero — Go-native WASM runtime; embeddable.
• Cloudflare Workers — V8 isolates that can run WASM modules from Rust / TinyGo / etc.

Component Model & WASI

• ★ WASI Preview 2 — standard ABI for WASM outside the browser; networking, filesystem, sockets all defined.
• ★ Component Model — composable WASM modules; "USB-C for languages."
• jco — JS host bindings for the Component Model; embed any WASM component in a Node / Bun / Deno app.
• wkg — package manager for WASM components.

When to reach for WASM

• CPU-heavy work in the browser — image decoding (@jsquash/*), video processing (ffmpeg.wasm), 3D physics (Rapier), DB engines (DuckDB-WASM, PGlite, SQL.js), regex (@biomejs/biome's parser).
• Sandboxing untrusted code — run customer-provided plugins in WASM (Shopify Functions, Figma plugins).
• Polyglot edge functions — write Rust / Go / Python and run on Workers / Compute / Spin.
• Offline desktop / mobile apps — Tauri can ship WASM modules.

Browser-specific things you can do with WASM

• Image / video codecs — WebP, AVIF, HEIC, JXL, AV1 via WASM ports.
• Local DBs — PGlite (Postgres), DuckDB-WASM, SQL.js, Wa-SQLite.
• CRDTs — Loro, Automerge, Yjs (parts).
• AI inference — ONNX Runtime Web, Transformers.js (with WebGPU + WASM fallback).
• PDF rendering — pdfium WASM ports.

Don't use WASM for

• DOM manipulation — overhead crossing the JS↔WASM boundary erases the gains.
• Tiny utility functions — JIT-ed JS is plenty fast.
• "I read a blog about it once and want to try" — pick a real bottleneck first.

Pick this if…

• Default Rust → browser: wasm-pack + wasm-bindgen.
• Default Go → browser: TinyGo.
• Embed a WASM component in a Node app: jco.
• Run customer plugins safely: WASI + Wasmtime; or Workers + WASM.
• Edge microservices in any language: Spin or Cloudflare Workers + WASM.
• You're not sure if you need WASM: you don't.