Business analysis glossary
HTTP Status Code
What it is
An HTTP status code is a three-digit number a server returns to say what happened to a request. Codes starting with 2 mean success, 4 mean the request had a problem and 5 mean the server failed. Common ones are 200 OK, 201 Created, 400 Bad Request, 401 Unauthorized, 403 Forbidden, 404 Not Found and 500 Internal Server Error.
Why it matters
Status codes let systems and testers know whether a call worked and why not. Requirements that name the expected code for each situation avoid confusion in testing and support. A status code is the first clue when debugging, so a precise list helps support staff distinguish a user mistake from a system outage.
Example
When a customer requests an order that does not exist at Marlow Online Store, the API returns 404 (not found). When the request has an invalid postcode, it returns 400 or 422 with an explanation. Having these agreed ahead of time means the tester can write an exact expected result for each situation rather than just checking that something happens.