For rspc to be able to convert your types into Typescript they must implement the specta::Type trait. Specta (opens in a new tab) is a crate that was created so that rspc can introspect Rust types. The Type trait allows the Typescript exporter to understand the fields, generics and dependant types of a Rust type.

The easiest way to implement the specta::Type trait is by using the specta::Type derive macro. We have already implemented most in-built types if you can find a missing one open a GitHub Issue (opens in a new tab).

use specta::Type;
pub struct MyStruct {
    pub name: String,
    pub age: i32,
pub enum MyEnum {
    // It is import MyStruct also implements `Type` or this will not work


You should be careful when using generics with type aliases (opens in a new tab) as you may run into situations where the types are not exported correctly. As far as we are aware this is a known limitation with Rust and is not something we can fix. If you run into this edge case you should change to using a struct instead of a type alias to workaround the problem.

Other languages

Specta stores information about your type which means an exporter for languages other than Typescript (opens in a new tab) could be made. If you are interested in supporting other languages, you can do so directly using the specta::Type trait in your own project, however a pull request to Specta would be appreciated.

Specta without rspc

Specta is an independent crate and can be used without rspc. Refer to it's documentation (opens in a new tab) for support using it.