[hn_throwaway_99]

Not sure I understand what you mean, or rather that all of this appears to be available in postgres.

pg_jsonschema is a postgres extension that implements schema validation for JSON columns. I'm not particularly familiar with Rust, so not sure exactly what you mean by "Rust-like enum typing", but postgres has enums, composite types, array types, and custom scalars, so not sure what's missing.

[throwaway894345]

By "Rust-like enums", I mean "sum types" or "algebraic data types". In general, it's a way of saying that a piece of data can have one of several different types/shapes (whereas a Postgres enum is basically just a label backed by an int). But yeah, with jsonschema you can probably express sum types, but jsonschema is disappointing for a bunch of reasons and needing an extension is also not great.