I don't know what you are trying to say. Any complex API will have to have some custom validation code. What we have been doing is using typescript interfaces[

I don't know what you are trying to say. Any complex API will have to have some custom validation code. What we have been doing is using typescript interfaces[1] to validate our API input data. This really makes the data validation painless for us. EDIT: Thinking about this a little more, this really only ensures that the provided data is the right "shape", there may still need to me more validation performed. [1] https://github.com/ysangkok/typescript-interface-to-jsonschema https://github.com/ysangkok/typescript-interface-to-jsonsche...