Application development - handling API errors

In general, an HTTP 200 indicates success, and any other status such as 4xx or 5xx indicates a problem.

Some APIs return a response payload, for example, a bit of JSON and contains its own status and/or error information. In this case, a 200 may indicate only that a response was delivered correctly and you still need to examine the status/errors properties of the response to decide if the call was truly successful or not. This is where having read and understood your APIs documentation is critically important.