[REQ] Generate different code for frontend and backend

Problem

Say I want to specify an endpoint for a sign-up use case.

POST /signup

The endpoint (on the frontend side) has a requestBody with a JSON:

{
  "email": "user@user.com",
  "password": "blaa",
  "passwordConfirm": "blaa"
}

The endpoint (on the backend side) should look like this:

{
  "email": "user@user.com",
  "password": "blaa",
  "passwordConfirm": "blaa",
  "handle": "username",
  "createdAt": "2021-05-28T12:39:47.802Z"
}

So there should be two more values, that only are handled by the backend side (createdAt and handle being initialized by the backend).

My goal is to generate the frontend and backend which should output different code:

• frontend: email, password, passwordConfirm
• backend: email, password, passwordConfirm, handle, createdAt

Describe the solution you'd like

No solution yet

Describe alternatives you've considered

No alternatives I've considered yet

Additional context

No additional context yet

The issue names no files, tests, or entry points. Start by clarifying how one OpenAPI request body should express frontend-only versus backend-only fields, then identify the generator paths for client and server output. Done means an agreed design and distinct generated representations for both sides, with tests covering the signup example.