Concepts

The behaviour no single endpoint owns: settlement, money, quotes, idempotency, attribution and limits.

These pages describe behaviour that no single endpoint owns. The first two are the ones that cause a rewrite when they are discovered late.

An order settles after the call that created it. Read this before you design anything.

Decimal strings on the wire, integer minor units underneath. Getting this wrong loses money quietly.

What you hold with us, how fresh the figure is, and why it is not a spending check.

A locked rate, single-use and short-lived.

The fee is its own named line beside the rate, and the total is the figure that moves. Mechanics, never numbers.

What makes a retry safe, on both order creation and webhook handling.

Which identifier is yours, which is ours, and what each one is for.

Request rate, order ceilings, and the 429 contract.

Why an endpoint in the reference answers 403 for your credential.

Which obligations are yours and which are ours.

Every rail in the corridor, what the API reaches today, and what each one does to your reference.