Rust
Wasmtime is a fast, standards-compliant WebAssembly runtime from the Bytecode Alliance. Its Rust crate lets you load, instantiate, and call WASM modules from a Rust host — making it ideal for host-side unit tests that verify WASM module behavior, test WASI system calls in a controlled sandbox, and validate component model
WebAssembly
WebAssembly performance is close to native — but "close" needs to be measured. Whether you're evaluating the overhead of crossing the WASM/JS boundary, comparing execution speed between runtimes, or profiling where your WASM module spends its time, you need specific tools: Criterion for Rust-level benchmarks, Wasmer
Rust
wasm-pack is the standard toolchain for building and testing Rust code compiled to WebAssembly. Its wasm-pack test command runs your Rust tests inside a real browser (headless Chrome, Firefox, or Safari) or under Node.js, giving you confidence that your WASM module behaves correctly in the environments where it will
Go
Go has had WebAssembly support since Go 1.11 via GOARCH=wasm GOOS=js, and since Go 1.21 via the WASI target GOOS=wasip1. Testing Go WASM code requires a different test runner than the standard go test command — either the wasm_exec.js Node.js harness for browser-targeted
WebAssembly
The WebAssembly Component Model is a standard for composing WASM modules with typed interfaces defined in WIT (WebAssembly Interface Types). It replaces ad-hoc ABI conventions with a formal type system — records, variants, options, results — and generates host and guest bindings automatically via wit-bindgen. Testing components means verifying these interfaces: that
WebAssembly
WebAssembly modules in browsers are instantiated via JavaScript and expose their functionality through JS exports. End-to-end and integration tests for WASM web apps use the same tools as regular web tests — Playwright for browser automation and Jest for unit-level JS/WASM integration — but with a few WASM-specific techniques: waiting for