# Inlet

> Crypto payment gateway. Create a payment in USD; the payer picks a network and coin; Inlet issues a fresh address and exact amount, watches the chain, and sends signed webhooks.

Base URL: https://api.inlet.cash/v1. Auth: `Authorization: Bearer inl_test_…` (test) or `inl_live_…` (live).

## Docs

- [Integration guide](https://api.inlet.cash/docs/integrate.md): create a payment, send the payer to the checkout, verify webhooks, test without coins, go live.
- [OpenAPI 3.1](https://api.inlet.cash/v1/openapi.json): every route and schema.
- Subscriptions: `POST /v1/subscriptions` schedules hosted invoices (a payment per period, emailed to the customer); mass payouts: `POST /v1/disbursements` (approved on the dashboard); on USDC the checkout pays by signature, Inlet pays the gas.
- Payment links (no code): `POST /v1/links` makes a public page (`url`) for a fixed price, an open amount or a tip jar; payments made through it are ordinary payments with `metadata.link_id`.

## Rules an integration must follow

1. Verify `Inlet-Signature` on every webhook with the webhook secret, over the raw body.
2. Deduplicate webhooks by event `id`; they are delivered at least once.
3. Fulfil on `payment.paid` from the webhook or from `GET /v1/payments/:id`, never from the browser.
4. Amounts: `price_amount` is US cents; token amounts are integer strings in base units.