[jaklfdjkasf]

This is very cool, but I highly recommend using a standard like JSON schema instead. It will make your life easier long term. The initial hurdle of learning may be harder, but lots of libraries/languages support JSON schema.

If you are using typescript, I highly recommend using a generator to create JSON schema definitions. This one has worked really well recently https://github.com/YousefED/typescript-json-schema

[pagnol]

Been using runtypes and it works well enough, but now I'm wondering if this may be a smarter option.