Declines

A declined payment is not an error. It is a successful call -- HTTP 200, a payment whose status is declined -- carrying a normalised decline block. Only transport and request problems are HTTP errors; a decline is a business outcome, and treating it as an exception is the first thing merchants get wrong.

Every normalised decline code has a page here: what it means, whether we retry or cascade for you, what you should do, and what to tell the payer. The taxonomy is one vocabulary across every provider, so you branch on our code, never on a raw processor string.