I prefer to use Zod or JSON Schema as the source of truth. Then I use QuickType [1] in the build process to generate code in different languages. This lets me share data structures. I mostly do this in Tauri apps to keep the same data shape in TypeScript and Rust. I also use it to define protocols, like for REST APIs.
Here are the advantages of this approach compared to using guts lib: - I get validation with clear error messages. - It supports many languages out of the box. - I don’t need to maintain a custom library. - JSON Schema is well supported in LLMs (for example, with structured output or vibe coding).
I know there exists more generic typing tools. One idea I had was to make a "guts" to convert Golang -> Generic Typing -> All languages.
The reason to keep Golang as the source of truth is these types originate from the backend. So when you are writing the backend, it is just the easiest place to write and maintain things. No obstacles.
Golang types are also very simple. I imagine almost all Go types can be converted because of that.