Payments for developers

Payment intents, hosted card fields, and where each piece of the flow has to run.

What they are, why payments need them, and what to do when your processor does not have them.

Three rules, two of which almost every first implementation gets wrong.

The sandbox proves the happy path. Here is how to make it show you the others, and what you have to fake yourself.

Six objects, thirty-odd statuses, and the handful that look final and are not.

A decline returns 201, the card cannot be reused, and a failed subscription waits for you. What to do about each.

Your handler will be called twice, late, out of order, and sometimes not at all. Here is how to make each of those harmless.

A payout is a sum. Here is how to rebuild it from the transactions underneath, to a fraction of a cent.

Scope is decided by what touches a card number, and one line of code can change it.

The billing loop is the easy half. Timing, state and failed payments are the other half.

How a card on file actually works, and the one step that turns a token into a reusable one.