# Generate Invoice

This endpoint enables you to generate a new invoice and obtain a payment URL for completing the transaction. By providing the required parameters in your request, you can specify the invoice amount and customize various options for the payment process.

## POST /payment/invoice

>

```json
{"openapi":"3.0.0","info":{"title":"Payments","version":"1.0.0"},"servers":[{"url":"https://api.oxapay.com/v1"}],"security":[],"paths":{"/payment/invoice":{"post":{"operationId":"generateInvoice","requestBody":{"required":true,"content":{"application/json":{"schema":{"type":"object","required":["amount"],"properties":{"amount":{"type":"number","format":"decimal","description":"The amount for the payment. If the currency field is not filled, the amount should be specified in dollars. If the `currency` field is filled, the amount should correspond to the specified currency."},"currency":{"type":"string","description":"Specify the currency symbol if you want the invoice amount calculated with a specific currency. You can also generate invoices in fiat currencies."},"lifetime":{"type":"integer","description":"Set the expiration time for the payment link in minutes.","minimum":15,"maximum":2880,"default":60},"fee_paid_by_payer":{"type":"number","format":"decimal","description":"Specify whether the payer will cover the invoice commission. 1 indicates that the payer will pay the fee, while 0 indicates that the merchant will pay the fee.","minimum":0,"maximum":1,"default":"Merchant setting"},"under_paid_coverage":{"type":"number","format":"decimal","description":"Specify the acceptable inaccuracy in payment. Determines the maximum acceptable difference between the requested and paid amount.","minimum":0,"maximum":60,"default":"Merchant setting"},"to_currency":{"type":"string","description":"The currency symbol of the cryptocurrency you want to convert to. You can only convert paid crypto currencies to USDT."},"auto_withdrawal":{"type":"boolean","description":"1 indicates that the received currency will be sent to the address specified in your Address List on the Settings page and 0 indicates that the amount will be credited to your OxaPay balance."},"mixed_payment":{"type":"boolean","description":"Specify whether the payer can cover the remaining amount with another currency if they pay less than the invoice amount. 1 allows the user to pay the remainder with a different coin, while 0 doesn't allow it.","default":"Merchant setting"},"callback_url":{"type":"string","description":"The URL where payment information will be sent. Use this to receive notifications about the payment status."},"return_url":{"type":"string","description":"The URL where the payer will be redirected after a successful payment."},"email":{"type":"string","description":"Provide the payer's email address for reporting purposes."},"order_id":{"type":"string","description":"Specify a unique order ID for reference in your system."},"thanks_message":{"type":"string","description":"A thanks message that brief note displayed to the payer after a successful payment."},"description":{"type":"string","description":"Provide order details or any additional information that will be shown in different reports."},"sandbox":{"type":"boolean","description":"The sandbox field is a boolean that specifies whether the API request should operate in sandbox mode (test environment). Set it to true for testing and false for live transactions."}}}}}},"responses":{"200":{"description":"Successful operation","content":{"application/json":{"schema":{"type":"object","properties":{"data":{"type":"object","properties":{"track_id":{"type":"string","description":"Unique identifier for the payment session in the OxaPay gateway. It is used to track the payment status, query details, and generate reports."},"payment_url":{"type":"string","description":"The URL of the payment page linked to the track ID. This link is shared with the payer to complete the payment process."},"expired_at":{"type":"integer","description":"The expiration timestamp (UNIX epoch) of the payment link. After this time, the link becomes invalid."},"date":{"type":"integer","description":"The creation timestamp (UNIX epoch) of the payment session."}}},"message":{"type":"string","description":"A message containing additional information about the result of the request."},"error":{"type":"object","description":"An object that provides details about any errors that occurred.","nullable":true,"properties":{"type":{"type":"string","description":"Type of the error"},"key":{"type":"string","description":"Key related to the error"},"message":{"type":"string","description":"Error message"}}},"status":{"type":"integer","description":"The status of the request response. Typically provided as a numeric code (e.g., 200 for success or other codes for errors)."},"version":{"type":"string","description":"The version of the API being used."}}}}}},"400":{"description":"Bad request","content":{"application/json":{"schema":{"type":"object","properties":{"data":{"type":"object","properties":{}},"message":{"type":"string","description":"A message containing additional information about the result of the request."},"error":{"type":"object","description":"An object that provides details about any errors that occurred.","nullable":true,"properties":{"type":{"type":"string","description":"Type of the error"},"key":{"type":"string","description":"Key related to the error"},"message":{"type":"string","description":"Error message"}}},"status":{"type":"integer","description":"The status of the request response. Typically provided as a numeric code (e.g., 200 for success or other codes for errors)."},"version":{"type":"string","description":"The version of the API being used."}}}}}}},"tags":["Invoice"],"parameters":[{"in":"header","name":"merchant_api_key","required":true,"schema":{"type":"string"},"description":"Your Merchant API Key for authentication and authorization."},{"in":"header","name":"Content-Type","required":true,"schema":{"type":"string","default":"application/json"}}]}}}}
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.oxapay.com/api-reference/payment/generate-invoice.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.