Wasm reactors require a host-provided WASI Preview 1 adapter. A reactor can run supported three.js CPU operations and send animated geometry, material state, and resource lifecycle notifications to an external web application through declared imports. The application supplies DOM, graphics, media, audio, and decoder bindings, including the renderer.

Library mode excludes promises, async functions, timers. See [WebAssembly Modules](/docs/wasm) for the embedding contract.