Fix: Minimal API JSON Options Not Applied

The Error

Response still camelCase:

{"firstName": "John"}

Quick Fix - 1 Min

1. builder.Services.ConfigureHttpJsonOptions(o => o.SerializerOptions.PropertyNamingPolicy = null). 2. Not Configure<JsonOptions> - that's for MVC. 3. Or app.MapGet("/", () => result).WithMetadata(new JsonOptionsAttribute())

Root Cause

Minimal APIs use HttpJsonOptions. MVC uses JsonOptions. Different services.