When developing code that uses web services I often code for the error case. What if I get back a 404 or 500? This is what I should do. I often have a hard time testing this. Some times the service provides a way to trigger errors. Those calls often are all about the payload.
I have started a new website httpresponsecodes.com that will take a code like 200 and give you back a 200 response. You can also set the body. For example http://www.httpresponsecodes.com/200?response_body=cow
Leaving of the response_body will return some details about the code. I dont have all the details on all the codes yet but 200 works fine. Its also one of the few that the browser renders fine.
Examples:
200 with body
200 with details of 200
500 with json http://www.httpresponsecodes.com/500?response_body={"zip":20}