Glossary

ProgrammableWeb's glossary of API and other technology terms and defination
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Error handling

In computer programming, error handling refers to how messages are sent to users when something goes wrong. Software programs rarely function as expected 100% of the time. Thus, when errors arise, error handling systems provide resolution measures to help developers and end-users respond to bugs. Applications that function on the web may encounter an error message if there is a malformed request, broken page, slow load times, unauthorized user, or if demands exceed a rate limit. Other factors can cause error messages too. Since web APIs utilize HTTP, API error handling adopts standardized HTTP error status codes (2XX, 3XX, 4XX, and 5XX). Error responses will usually include one of these error numbers along with a human-readable message. For example, a common error code is 504, which denotes the server took to long to respond; it "timed out." Proper error handling is essential to developers as it increases software performance visibility, aids testing, and directs resolution attempts.