• Just write down some normal Rust code (even with arbitrary types, closure, &mut, async, etc)
• And call it from Flutter, as if Rust code is normal Flutter code
• The bridge will generate all needed glues in between

Create a working Flutter + Rust app and see it live, by running:

cargo install 'flutter_rust_bridge_codegen@^2.0.0-dev.0' && \
    flutter_rust_bridge_codegen create my_app && cd my_app && flutter run

(Optional) Edit rust/src/api/simple.rs (e.g. Hello -> Hi), then see the change by:

flutter_rust_bridge_codegen generate && flutter run

For more elaborated quickstart, please visit this page.

This package is officially Flutter Favorite, and is in the first batch of 7 packages at its rebooting.

• Rapid setup: Only a one-liner command to integrate into your project.
• Write your code naturally: Use your intuition and write the code you want. The bridge understands many advanced grammars (see below), allowing seamless calling Rust from Dart.
• Use libraries/tools in Flutter/Rust: All existing libraries, Flutter debuggers, ... Nothing to stop you from using them.

• Arbitrary types: Use arbitrary Rust and Dart types without manual intervention, even if they are not serializable or non-clone.
• Async & sync x Rust & Dart: Multi modes for various needs - Async Dart to avoid blocking the main thread, sync Dart for places needed (e.g. Widget.build); async Rust for IO bound tasks, thread pools for CPU-heavy computations.
• Two-way road: Not only can Dart call Rust - Rust can also call Dart.
• Auto-translatable types: Lots of types can be further translated to Dart native types, e.g. complex enums and structs, zero-copy big arrays, errors (Result), and Streams (iterator).
• Auto safety: Focus on your code, and forget memory safety, malloc/free, or undefined behavior completely.
• Customizable & bare-metal mode: Provide sensible defaults, but everything (loader, handler, ...) can be customized. You can even throw all away and only use the bare minimum calling.
• Cross-platform: Support Android, iOS, Windows, Linux, MacOS, and Web.
• Other features, e.g. support whole folders as input, pure-Dart compatible, instance and static methods, ...

• Solid CI: Valgrind & sanitizers (ASAN/MSAN/LSAN) for memory/UB-related bugs, testing per platform per mode, benchmarking, test coverage, post-release, etc, all guaranteed by CI.
• Used by many people: See here for an incomplete list.
• Easy to code-review & convince yourself: This package simply simulates how humans write boilerplate code. If you want to convince yourself (or your team) that it is safe, there is not much code to track.
• Fast: It is only a thin (though feature-rich) wrapper, benchmarked on CI, and even has multiple codecs for best performance under different workloads.
• Hackable: If (for whatever reason) you want to hack the source, there are contributor guides, code is modular, and the execution logic is intuitive.
• Ask questions: Feel free to ask questions in the issue tracker, and I usually reply within hours (if not sleeping).

Simple Rust...

fn f(a: String, b: Vec<String>) -> MyStruct { ... }

...called from Dart, without manual intervention.

print(f(a: 'Hello', b: ['Tom']));

Let's see how fancy we can support:

// ↱ Arbitrarily fancy Rust types
struct Garden { land: whatever::fancy::Land }

// ↱ Complex but auto-translatable
enum Tree { A { name: (String, i32), children: Option<Vec<Tree>> }, B }

// ↱ Support functions & methods
impl Garden {
    // ↱ Allow async & sync Rust
    async fn plant(
        // ↱ Support T/&T/&mut T
        &mut self,
        tree: Tree,
        // ↱ Rust can also call Dart
        chooser: impl Fn(String) -> bool,
        // ↱ Error translation ; zero copy
    ) -> Result<Vec<u8>, FancyError> {
        ...
    }
}

Still seamlessly call in Dart:

var tree = Tree.a(('x', 42), [Tree.b()]);
// ↱ Async & sync Dart
print(await garden.plant(tree, (a) => true));

Check out the documentation for quickstart, full guides and more.

Here is my another open-source library :) https://github.com/fzyzcjy/flutter_smooth.

Firstly, I want to sincerely thank Dart, Flutter and Rust (alphabetical order). Dart provides a solid foundation for productive UI development, Flutter enables developers to make cross-platform apps with ease, and Rust empowers everyone to build reliable and efficient software. Without the languages and frameworks, this bridge connects absolutely nothing. Besides, I also want to express my thanks for conferring the official Flutter Favorite honor to the package. In addition, I also want to say thanks to the Dart, Flutter and Rust team members as well as community members, who have helped me during the development of flutter_rust_bridge by valuable discussions, insights, and actions.

Secondly, thanks goes to these wonderful contributors (emoji key following all-contributors specification):

fzyzcjy 💻 📖 💡 🤔 🚧	Viet Dinh 💻 ⚠️ 📖	rogurotus 💻 📖	Nicolas Gasull 💻	Joshua Wade 💻	Lattice 0 💻 📖	Unoqwy 💻
Anton Lazarev 💻	sagu 💻 📖	Sebastian Urban 💻	Rom's 💻 📖	老董 💻 📖	Gregory Conrad 📖 💻	huang12zheng 💻 📖
Daniel 💻	Manuel Philipp 💻 📖	SoLongAnd... 💻 📖	hsfzxjy 💻	Cupnfish 💻	alanlzhang 💻 📖	Erikas Taroza 💻
菘菘 💻	SimplyKyle! 💻	Zaitam 💻	Brent Lewis 💻 📖	nitn3lav 💻 📖	Alex Procelewski 📖 💻	Kevin Li 💻 📖
Daniel Porteous (dport) 📖	Andreas Monitzer 💻	Kim Dong-Hyun 💻 📖	NightFeather 💻	九月 💻	Wouter Ensink 📖	Marcel 💻
Aidan 📖	Patrick Auernig 💻	Sai Chaitanya 💻	Xidorn Quan 💻	jsonmona 💻	codercengiz 💻	Michael Bryan 💻
Philip Kannegaard Hayes 💻	bus710 📖	._. 📖	Marc Gutenberger 💻	Andrii Stadnik 💻	Aran Donohue 💻	syndim 💻
Ares Andrew 📖	polypixeldev 📖	CicadaCinema 💻 📖	Fabian Löschner 💻	Vincent Herlemont 💻	Roman Zaynetdinov 📖	raphaelrobert 📖
Mouayad Alhamwi 📖	elliotsayes 📖	muji 📖	thomas725 📖	orange soeur 📖	Alex Gorichev 📖	Sven-Hendrik Haase 📖
Chris Ohk 📖	Vitalii Hurianov 📖	Sam Nystrom 📖	max 📖	Jonathan 📖	Akash Jaiswal 📖	Febrian Setianto 📖
Satvik Pendem 💻	Damien Wise 📖	wxitcode 📖	rustui 📖	J 📖	Ikko Ashimine 📖	thesimplekid 📖

More specifically, thanks for all these contributions:

• Desdaemon: Support not only simple enums but also enums with fields which gets translated to native enum or sealed freezed class in Dart. Support the Option type as nullable types in Dart. Support Vec of Strings type. Support tuple type. Support comments in code. Add marker attributes for future usage. Add Linux and Windows support for with-flutter example, and make CI works for that. Avoid parameter collision. Overhaul the documentation and add several chapters to demonstrate configuring a Flutter+Rust project in all five platforms. Refactor command module. Precompiled binary CI workflow. Fix bugs. Add support for the Web platform, parallel to the existing mobile/desktop platforms, via WASM and JavaScript as intermediate values. GitHub retry actions. Implement draft of opaque types. Refactor Boxed and Option. Impl list of dates and optionals. Parameter defaults. Refactor CLI. Refactor codegen errors.
• rogurotus: Add Rust opaque types, enabling arbitrary Rust structs to be used as opaque Dart objects by generating wrappers and raw Arc pointers. Also add Dart opaque types, allowing to use any Dart objects in Rust code. Extend SyncReturn for more types. Fix generation bug. Fix SyncReturn. Migrate to dart-sys. Update CI. Fix linters. Fix SyncReturn bug.
• ngasull: Make sync mode support whatever types that classical async mode supports. Bump sdk.
• SecondFlight: Allow structs and enums to be imported from other files within the crate by creating source graph. Auto-create relevant dir. Fix store_dart_post_cobject error with ffigen 6.0.
• lattice0: Implement hierarchy of exceptions. Support methods, such that Rust struct impls can be converted to Dart class methods. StreamSink at any argument.
• Unoqwy: Add struct mirrors, such that types in the external crates can be imported and used without redefining and copying.
• antonok-edm: Avoid converting syn types to strings before parsing to improve code and be more robust.
• sagudev: Make code generator a lib. Add error types. Depend on cbindgen. Fix LLVM paths. Update deps. Fix CI errors.
• surban: Support unit return type. Skip unresolvable modules. Ignore prefer_const_constructors. Non-final Dart fields.
• Roms1383: Fix build_runner calling bug. Remove global ffigen dependency. Improve version check. Fix enum name-variant conflicts. Support Chrono date time and UUID types. Migrate to Rust 1.64 workspace. Update and refactor CI. Update header comments. Code cleanup.
• dbsxdbsx: Allow generating multiple Rust and Dart files. Fix lint. Update doc. Add logging.
• GregoryConrad: Add doc to setup frb inside a Dart/Flutter library.
• huang12zheng: Support type aliases and nested ones. Tweak code generation. Fix rust_build_and_test on Mac. Improve CI logic and cache. Remove bridge field in model.
• trobanga: Add support for [T;N] structs. Add usize support. Add a cmd argument. Separate dart tests. Fix fallible list case. Fix test compile. Fix Result + RustAutoOpaque.
• MnlPhlp: Support macros and will auto expand. Allow mirror types in streams.
• SoLongAndThanksForAllThePizza: Refactor and enhance SyncReturn to support more types. Refactor post-release CI.
• hsfzxjy: Fix SyncReturn use-after-free bug.
• Cupnfish: Support arrays as function parameters. Allow multi mirror.
• alanlzhang: Add generation for Dart metadata. Enhance module parser. Fix enum in struct. Fix linter.
• erikas-taroza: Support list of primitive enums. Make enum camelCase. Warn wrong path. Fix cargo expand.
• SiongSng: Finish implementing exception hierarchy. Fix SyncReturn bug.
• JustSimplyKyle: Also finish implementing exception hierarchy.
• Zaitam: Fix when method return struct. Partial migration to Dart 3.
• coder0xff: Discuss binding unmodified Rust. Refactor SupportedInnerType. Extra codegen tester.
• nitn3lav: Nested structs without Box.
• alexthe2: Add Option Datetime. Add empty structs. Improve doc. Add r#. Fix mirror enum bug.
• AlienKevin: Add flutter example for macOS. Add doc for Android NDK bug.
• banool: Fix pubspec parsing. Fix symbol-stripping doc.
• anlumo: Fix freezed + methods. Non-clone RustOpaque.
• temeddix: Fix broken CI. Custom num workers. Fix MacOS doc steps. Update doc. Make zero-copy defaultable.
• NightFeather0615: Fix Vec bool.
• OfficialBoyfriend: Fix error display.
• w-ensink: Improve doc. Fix CI. Refactor. Add tests.
• smw-wagnerma: Improve Windows encoding handling.
• powpingdone: Document JNI init and libc++_static linking.
• valeth: Rename callFfi's port.
• sccheruku: Prevent double-generating utility.
• upsuper: Refactor delegate-attr.
• jsonmona: Add import.
• codercengiz: Fix mirroring bug.
• Michael-F-Bryan: Detect broken bindings.
• phlip9: Fix no-serde compilation.
• bus710: Add a case in troubleshooting.
• Demezy: Mention troubleshooting.
• gutenfries: Bump proc-macros.
• anstadnik: Check keywords.
• aran: Fix pubspec. Bump version.
• syndim: Add a bracket to box.
• TENX-S: Improve doc. Reproduce a bug.
• polypixeldev: Improve doc.
• CicadaCinema: Bump version. Improve doc.
• w1th0utnam3: Improve message.
• vincent-herlemont: Loosen version.
• zaynetro: Improve doc.
• raphaelrobert: Remove oudated doc.
• DMouayad: Improve doc.
• elliotsayes: Improve doc.
• tmpfs: Improve doc.
• thomas725: Improve doc.
• juzi5201314: Improve doc.
• Voklen: Improve doc.
• svenstaro: Improve doc.
• utilForever: Fix typos.
• not-holar: Fix typos.
• Stonks3141: Fix doc credit.
• vimaxwell: Fix doc link.
• lker-dev: Fix doc link.
• jaiakash: Fix doc link.
• feber: Fix doc link.
• satvikpendem: Little co-work #989.
• damywise: Fix a typo.
• wxitcode: Fix a typo.
• rustui: Fix a typo.
• escwxyz: Fix a typo.
• eltociear: Fix a typo.
• thesimplekid: Fix a typo.