Contrary to some others experience here I've had good results writing OpenAPI YAML and generating server stubs in Spring. Because it's generating strongly typed code we get a lot of guarantees that the docs match the implementation. For working with frontend devs it's a huge win over the lossy communication of word-of-mouth API docs.

It is definitely verbose to write and Moonwalk would help. Co-pilot helps a huge amount, but I do crave a DSL that's not indentation based.