Developer documentation
Build commerce on the order, not the charge
Orders, payments, subscriptions, and invoices on one API. Start from a quickstart, then drill into field-level reference when you need it.
Any future expiry, any CVC. Works on every test-mode checkout. See Testing for declines and 3D Secure.
Guides
Task-based guides for each part of the integration.
Get started
The shortest path to a test payment.
Payments
Take a payment against an order, in your UI or on Flint's.
Checkout and payment links
Hosted collection surfaces and how to choose between them.
Order pricing
Tips, fees, tax, and discounts on the order.
Headless
Own the checkout, the buyer account, or both, on your own domain.
Returns
Take merchandise back, and settle what the buyer is owed.
Invoicing
Customer accounts
Where buyers track orders, manage subscriptions, and start returns.
Reliability
Webhooks, retries, and failure handling.
Operations
Run Flint in production: money movement and disputes.
Migrations
AI & agents
Build agentic and headless integrations on Flint.
API reference
Every resource, endpoint by endpoint, with request and response shapes.