application/wasm
applicationThe MIME type for WebAssembly binary modules. Browsers require WebAssembly files to be served as application/wasm for streaming compilation (WebAssembly.instantiateStreaming). Serving with the wrong type (application/octet-stream) forces buffer-based compilation which is slower and prevents streaming.
Details
application/wasm is defined by the W3C WebAssembly Core Specification and IANA-registered.
Streaming compilation: WebAssembly.instantiateStreaming() starts compiling as bytes arrive. It requires the server to return application/wasm. If the wrong type is returned, browsers throw a TypeError and fall back to the slower WebAssembly.instantiate() with a buffer.
Server config: ensure your web server maps .wasm → application/wasm. nginx and Apache may not have this mapping by default.
nginx config: types { application/wasm wasm; }
Content-Encoding: WebAssembly binaries should be served with gzip or brotli Content-Encoding (they compress well). Do NOT ship .wasm.gz – use content negotiation and Content-Encoding instead.
Common use
WebAssembly module delivery for browser applications