What common mistake do developers make with Json responses, why does the mistake cause problems, and what is the safer approach?

What common mistake do developers make with Json responses, why does the mistake cause problems, and what is the safer approach? One recurring problem with JSON responses is applying it without understanding the boundary it protects. Always returning status 200 for errors instead of using HTTP status codes that describe the result of the request. In addition, JSON responses are useful for APIs, AJAX requests and browser applications that consume structured data. Safer engineering approach: keep the responsibility in the correct layer, use the framework's supported API, validate and authorize inputs, avoid hidden side effects, and verify the behavior with tests.