JSON is popular because it's schemaless; storing and versioning schemas is its own nightmare of inconsistent and inefficient hacks.
However, in practice, JSON messages almost always have an implied schema. Figuring it out on the fly shouldn't be too hard - just apply the JIT and type inference technologies that compilers have already used for decades.
(Not a problem with an immediately obvious solution, but that's why we're here, no?)
> However, in practice, JSON messages almost always have an implied schema.
Typed json already exists in various attempts eg tjson
Really I think the problem is that JSON is great when your schema is still in flux -- once it's public/stable, it makes sense to want to strictly encode the current schema.
The solution then is that you really want a way to trivially transition from "implied schema" to "strict schema" -- though a typed json won't help you too much because the larger trouble is figuring out what your schema is in practice. I guess you really want either a code analysis tool to determine it, or more likely an automated tool to take eg a list of json responses (probably based on a test suite/code coverage) and produce a typed json schema that you can simply drop into your public API
Do you mean "JSON with a schema" (there are multiple such) or "JSON decoding to static types" (without reflection).