Specta

Easily export your Rust types to other languages

Features

• Export structs and enums to multiple languages
• Get function types to use in libraries like tauri-specta
• Supports wide range of common crates in Rust ecosystem
• Supports type inference - can determine type of fn demo() -> impl Type

Language Support

Language	Status	Exporter	Features
TypeScript	✅ Stable	specta-typescript	Full type support, generics, unions
Swift	✅ Stable	specta-swift	Idiomatic Swift, custom Codable, Duration support
Rust	🚧 Partial	specta-rust	Basic types work, structs/enums in progress
OpenAPI	🚧 Partial	specta-openapi	Primitives work, complex types in progress
Go	🚧 Planned	specta-go	Go structs and interfaces
Kotlin	🚧 Planned	specta-kotlin	Kotlin data classes and sealed classes
JSON Schema	🚧 Planned	specta-jsonschema	JSON Schema generation
Zod	🚧 Planned	specta-zod	Zod schema validation
Python	🚧 Planned	specta-python	Python dataclasses and type hints
C#	🚧 Planned	specta-csharp	C# classes and enums
Java	🚧 Planned	specta-java	Java POJOs and enums

Legend

• ✅ Stable: Production-ready with comprehensive test coverage
• 🚧 Partial: Basic functionality implemented, complex types in progress
• 🚧 Planned: In development or planned for future release

Implementation Status

The Specta ecosystem is actively developed with varying levels of completeness:

• Production Ready (2): TypeScript and Swift exporters are fully functional with comprehensive test coverage
• Partially Implemented (2): Rust and OpenAPI exporters have basic functionality working, with complex types in progress
• Planned (7): Go, Kotlin, JSON Schema, Zod, Python, C#, and Java exporters are in development

For the most up-to-date status of each exporter, check the individual crate documentation and issue trackers.

Ecosystem

Specta can be used in your application either directly or through a library which simplifies the process of using it.

• rspc - Easily building end-to-end typesafe APIs
• tauri-specta - Typesafe Tauri commands and events
• TauRPC - Tauri extension to give you a fully-typed IPC layer.

Usage

Add the specta crate along with any Specta language exporter crate:

# Core Specta library
cargo add specta

# Language exporters (choose one or more)
cargo add specta_typescript  # TypeScript (stable)
cargo add specta_swift       # Swift (stable)
cargo add specta_rust        # Rust (partial - basic types)
cargo add specta_openapi     # OpenAPI/Swagger (partial - primitives)
# cargo add specta_go          # Go (planned)
# cargo add specta_kotlin      # Kotlin (planned)
# cargo add specta_jsonschema  # JSON Schema (planned)
# cargo add specta_zod         # Zod schemas (planned)

Then you can use Specta like following:

TypeScript Example

use specta::{Type, TypeCollection};
use specta_typescript::Typescript;

#[derive(Type)]
pub struct TypeOne {
    pub a: String,
    pub b: GenericType<i32>,
    #[serde(rename = "cccccc")]
    pub c: MyEnum,
}

#[derive(Type)]
pub struct GenericType<A> {
    pub my_field: String,
    pub generic: A,
}

#[derive(Type)]
pub enum MyEnum {
    A,
    B,
    C,
}

fn main() {
    let types = TypeCollection::default()
        // You don't need to specify `GenericType` or `MyEnum` because they are referenced by `TypeOne`
        .register::<TypeOne>();

    Typescript::default()
        .export_to("./bindings.ts", &types)
        .unwrap();

    // if you need more control over file saving
    assert_eq!(
        Typescript::default().export(&types).unwrap(),
        r#"// This file has been generated by Specta. DO NOT EDIT.

export type GenericType<A> = { my_field: string; generic: A };

export type MyEnum = "A" | "B" | "C";

export type TypeOne = { a: string; b: GenericType<number>; cccccc: MyEnum };

"#
    );
}

Multi-Language Export Example

You can export the same types to multiple languages:

use specta::{Type, TypeCollection};
use specta_typescript::Typescript;
use specta_swift::Swift;

#[derive(Type)]
pub struct User {
    pub id: u32,
    pub name: String,
    pub email: Option<String>,
}

fn main() {
    let types = TypeCollection::default()
        .register::<User>();

    // Export to TypeScript (stable)
    Typescript::default()
        .export_to("./types.ts", &types)
        .unwrap();

    // Export to Swift (stable)
    Swift::default()
        .export_to("./Types.swift", &types)
        .unwrap();

    // Note: Other exporters are in development
}

A common use case is to export all types for which specta::Type is derived into a single file:

//! NOTE: This example requires the `export` feature on the `specta` crate
use specta::Type;
use specta_typescript::Typescript;

#[derive(Type)]
pub enum MyEither<L, R> {
    Left(L),
    Right(R),
}

#[derive(Type)]
pub struct GenericType<A> {
    pub my_field: String,
    pub generic: A,
}

#[derive(Type)]
pub enum MyEnum {
    A,
    B,
    C,
}

#[derive(Type)]
#[specta(export = false)]
pub struct DontExportMe {
    field: String,
}

fn main() {
    Typescript::default()
        .export_to("./bindings.ts", &specta::export())
        .unwrap();
}

Check out the docs for more information.

Motivation

This library was originally created to power the type exporting functionality of rspc, but after building it we realized that it could be useful for other projects as well so we decided to move it into a dedicated library.

A huge thanks to Brendonovich for doing a heap of early development on this library.