I should have been clear. Yes it is avoidable but only by adding more checking machinery. The bare language doesnt help.

In Go etc. If a struct doesn't a field foo then there will not be a field foo at runtime. In JS there might be. Unless you bring in libraries to help prevent it.

You are relying on someone remembering to use zod on every fetch

OpenAPI can do this too

huh? does Java even support marshall/unmarshall json in the 'bare' language?