Simplify Response Structure via Final Response Converter

[stdOWL]

Although error responses return data: null at runtime, the field is not defined in the Swagger/OpenAPI schema.

Why It Matters
• Codegen tools (TypeScript, Kotlin, Swift) don’t expect data, causing type or runtime errors.
• Developers avoid using undocumented fields, leading to confusion.

Recommendation

Explicitly define the data field (as nullable) in error response schemas.
This ensures consistency between runtime behavior and API documentation.

[akutayural]

Hey, really good catch. You’re absolutely right that data is currently sent as null in error cases, but it isn’t explicitly defined as nullable in the OpenAPI schema.

I hadn’t run into issues myself because most of my projects just ignored that field when it was null, but for TypeScript/Kotlin/Swift clients using codegen, this could definitely throw type errors.

Totally agree we should make data explicitly nullable in the schema so the docs match what’s actually returned at runtime. I was already thinking of updating this with the new version v01.1.17.

If you’d like to contribute directly to this (or any other improvement), you’re more than welcome to open a PR. I’m keeping the main branch protected, but contributions and ideas are always appreciated! We can release this feature in the v0.1.17.