http
POST /api/users HTTP/1.1
Host: api.example.com
Content-Type: application/json
{"username": "alice", "email": "alice@example.com"}
HTTP/1.1 201 Created
Location: /api/users/42
Content-Type: application/json
{"id": 42, "username": "alice", "email": "alice@example.com", "created_at": "2025-10-01T14:30:00Z"}