| Payment | A single invoice created via the API, paid on-chain by a customer, and resolved to a terminal status. |
| Payment UID | The payment's UUID (paymentUid / paymentId). Your correlation key for the callback, webhook, and verify — and, in API mode, the credential. |
| Hosted Checkout | The Finomesh-hosted payment page you redirect customers to. The default mode. |
| API Mode | Embedded checkout — you render your own payment page and drive the flow server-to-server. IP-allowlisted. |
| Callback | The browser redirect to your callbackUrl after a hosted payment resolves. Forgeable — a UX hint, not authoritative. |
| Webhook | The signed server-to-server POST to your webhookUrl on a terminal status. A reliable trigger — still not the source of truth. |
| Verify | POST /payments/{id}/verify — the authoritative read returning the real status and amounts. Fulfil only on this. |
| Offer | One payable crypto asset on a payment, with its amount, fees, and total. Served in offers[]. |
| Asset | A specific crypto token on a specific network (e.g. USDT on TRON). |
| Gateway | Your integration's container — owns its API key, enabled assets, fee settings, and webhook secret. |
| Settlement | A payout of your balance to an external address (also called cashout). |
| Cashout | Withdrawing your gateway balance, via the dashboard or the (off-by-default) cashout API. |
| Idempotency Key | A client-supplied header that makes settlement creation safe to retry without duplicating the payout. |
| Signature | The HMAC that authenticates a webhook (X-Webhook-Signature) or a cashout request (X-Signature). |
| Allowlist | The set of server IPs permitted to make API-mode and cashout calls for a gateway. |
| Amount Deviation | How a slightly-off payment is judged against your tolerance → SUCCESS / ACCEPTABLE / MISMATCH. |
| Acceptable Payment | A payment paid within your configured tolerance (ACCEPTABLE) — safe to fulfil. |
| Mismatch Payment | A payment paid outside tolerance (MISMATCH) — hold for manual review. |
| Expired Payment | An unpaid payment past its deadline (EXPIRED, terminal). |