specta-typescript 0.0.14

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

Legend

• ✅ Stable: Production-ready with comprehensive test coverage
• 🚧 Partial: Basic functionality implemented, complex types in progress

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 (10): Rust, OpenAPI, Go, C#, Java, Kotlin, JSON Schema, Zod, Valibot, and Python have broad type support but are still stabilizing
• Planned (0): All currently listed exporters have an initial implementation

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)
cargo add specta_openapi     # OpenAPI 3.0 schemas (JSON or YAML)
cargo add specta_java        # Java 17 (partial)
cargo add specta_go           # Go (partial)
cargo add specta-python      # Python 3.13 type hints (partial)
cargo add specta_kotlin       # Kotlin (partial)
cargo add specta_jsonschema   # JSON Schema (partial)
cargo add specta_zod          # Zod schemas (partial)
cargo add specta-valibot      # Valibot schemas (partial)
cargo add specta-csharp       # C# (partial)

Then you can use Specta like following:

TypeScript Example

use specta::{Type, Types};
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 = Types::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, Types};
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 = Types::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(collect = 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.

Releasing

Publishing to crates.io uses crates.io trusted publishing: the release workflow exchanges its GitHub OIDC identity for a short-lived crates.io token, so no long-lived CARGO_REGISTRY_TOKEN is stored in this repository or in Actions secrets.

One-time setup — a crate owner adds a trusted publisher in the crates.io UI (the crate's Settings → Trusted Publishing) for every crate in the workspace. These values must match .github/workflows/release.yml exactly, or the token exchange is refused:

The workflow publishes the whole workspace, so each of the following crates needs its own trusted publisher: specta, specta-macros, specta-serde, specta-util, specta-typescript, specta-swift, specta-openapi, specta-jsonschema, specta-kotlin, specta-csharp, specta-go, specta-python, specta-java, specta-zod, specta-valibot, specta-rust and specta-rescript.

A trusted publisher can only be configured once a crate exists on crates.io, and the initial publish requires an API token. specta-valibot, specta-rust and specta-rescript have never been released, so publish each of them once from your machine before adding its trusted publisher.

Adding required reviewers to the release GitHub environment is recommended: it turns publishing into an approved action rather than something any tag push does.

Cutting a release:

1. Bump the version of every workspace crate (the tag names the specta crate version) and merge to main. The exporters pin specta to an exact version, so each one has to be republished whenever specta changes, and Cargo refuses to publish a version that already exists on crates.io.

2. Tag the merge commit and push the tag:

   git tag v2.0.0-rc.27
   git push origin v2.0.0-rc.27
   

The release workflow then verifies the release (the tag matches the specta crate version, and the workspace builds and tests), publishes every crate to crates.io, and creates the GitHub release.