flutter_rust_bridge_codegen can also generate code to run in browsers using wasm_bindgen. To generate a WASM-specific file, pass this option to your invocation:

flutter_rust_bridge_codegen .. --wasm

By default this will create several new files:

├── lib
│   ├── ...
│   ├── bridge_generated.io.dart
│   └── bridge_generated.web.dart
└── native/src
    ├── bridge_generated.io.rs
    └── bridge_generated.web.rs

The .io and .web modules implement platform-specific helpers. This split is mandatory for Dart due to its module system, however if you prefer to keep the Rust bridge in a single file pass the --inline-rust flag as well.

Check out Integrating with Web for instructions on how to consume the web bridge.

have a look at issue 860