# Invoices

An invoice is a fiat-priced payment request. You create it through the **API** or **admin panel**; Cryptonly returns a hosted **payment page URL** (`paymentPageUrl`) that you send to the customer.

The customer opens the payment page, picks a cryptocurrency, and pays to a **unique deposit address** assigned for that attempt only. Cryptonly monitors the blockchain, runs compliance checks, and settles the payment into your merchant balance.

Invoice amounts are always expressed in **fiat** (for example USD or EUR). The crypto amount is calculated at checkout from live rates when the customer selects a currency.

![Payment flow](../../../../assets/payment-flow.png)

## Amount and line items

Provide at least one of `amount` or `items` when creating an invoice. You can send both.

* If a **positive `amount`** is sent, it is always the charged total — even when `items` are also sent.
* If `amount` is omitted, the total is computed as the sum of `cost × quantity` across `items`.
* Line items are stored and shown on the hosted payment page regardless of how the total was set. They do not change the charged amount when `amount` is present.

## How status and webhooks work

Invoices have [statuses](https://docs.cryptonly.net/guides/invoices/statuses.md). Cryptonly sends a signed `invoice.statusChanged` webhook when the invoice **status** changes.

Important behaviors for integrators:

* On create, the invoice starts in `created` and you receive one webhook with status `created`.
* When the customer selects a currency and a deposit address is generated, the invoice **stays** `created` — there is no extra status and no second `created` webhook. If the customer switches currency, the invoice still stays `created`.
* When an on-chain transaction is first detected, the invoice moves to `processing`, then to a settled status (`paid`, `partially_paid`, or `overpaid`) or to `suspended` (compliance review) or `failed`.
* An invoice that ends in `expired` or `cancelled` without payment is closed. An `expired` invoice can still move to `processing` if a payment reaches its deposit address within **4 hours** — see [Late payments](https://docs.cryptonly.net/guides/invoices/statuses.md#late-payments).

Linked deposits do **not** send `deposit.statusChanged` webhooks. Listen for `invoice.statusChanged` for checkout payments.

## Related pages

- [Processing lifecycle](https://docs.cryptonly.net/guides/invoices/processing-lifecycle.md): Full step-by-step flow
- [Statuses](https://docs.cryptonly.net/guides/invoices/statuses.md): Status table and integration notes
- [Webhooks](https://docs.cryptonly.net/api-reference/webhooks.md): invoice.statusChanged verification and payloads
- [Deposits](https://docs.cryptonly.net/guides/deposits.md): Standalone top-ups, which use a different webhook