{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://raw.githubusercontent.com/api-evangelist/now-payments/refs/heads/main/json-schema/invoice.json",
  "title": "Invoice",
  "description": "Schema for a NOWPayments payment invoice object",
  "type": "object",
  "properties": {
    "id": {
      "type": "integer",
      "description": "Unique invoice identifier"
    },
    "order_id": {
      "type": "string",
      "description": "Merchant-defined order identifier"
    },
    "order_description": {
      "type": "string",
      "description": "Human-readable order description"
    },
    "price_amount": {
      "type": "number",
      "description": "Invoice amount in fiat currency"
    },
    "price_currency": {
      "type": "string",
      "description": "Fiat currency code (e.g. usd, eur)"
    },
    "pay_currency": {
      "type": ["string", "null"],
      "description": "Preferred payment cryptocurrency, null if not specified"
    },
    "ipn_callback_url": {
      "type": "string",
      "format": "uri",
      "description": "URL for IPN callback notifications"
    },
    "invoice_url": {
      "type": "string",
      "format": "uri",
      "description": "Hosted payment page URL for the customer"
    },
    "success_url": {
      "type": "string",
      "format": "uri",
      "description": "URL to redirect customer after successful payment"
    },
    "cancel_url": {
      "type": "string",
      "format": "uri",
      "description": "URL to redirect customer if payment is cancelled"
    },
    "created_at": {
      "type": "string",
      "format": "date-time",
      "description": "Invoice creation timestamp"
    },
    "updated_at": {
      "type": "string",
      "format": "date-time",
      "description": "Invoice last update timestamp"
    }
  },
  "required": ["id", "price_amount", "price_currency", "invoice_url"]
}