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Response handling

Response handling is an important aspect of processing callbacks in the IXOPAY platform payment processing workflow. Ensuring that your system responds with the appropriate status code and content not only acknowledges the receipt of the notification but also helps avoid potential delays or duplicate notifications.

To further enhance your understanding of callback handling in IXOPAY platform, explore the following articles:

  • Callback data: Detailed information on the structure and format of callback data.
  • Notification types: Learn about the different types of notifications sent by IXOPAY platform.

Callback URL restrictions

To ensure successful callback processing, adhere to the following technical restrictions for callback URLs:

  • The callback URL must conform to the URI format defined by RFC 3986.
  • The scheme part of the URI must be either http or https.
  • The host part of the URL must not be empty.
    • If the host is a hostname, it must resolve to a valid IPv4 address (via a DNS A record).
  • The (resolved) IPv4 address of the host part must not be
    • a private IP address (RFC 1918:,,, or
    • a reserved IP address (RFC 3232:, RFC 3927:, RFC 6890:,,,
  • The port part of the URI must be either 80 or 443.
Allow-listing other ports

If your system architecture requires a port other than the standard HTTP or HTTPS ports, please contact our support team at [email protected] to request an exception to this rule. Please provide both the host CIDR and the ports you want to allow-list.

Handling callbacks

To handle callbacks effectively, follow these general steps:

  • Implement a callback endpoint in your system to receive notifications from IXOPAY platform.
  • Ensure that a callbackUrl field is set on the transaction to specify the callback endpoint where notifications should be sent. Alternatively, you can enable callbacks on the connector settings.
  • Optionally, validate the authenticity of the received notification using the provided request signature.
  • Process the received notification data according to your business logic.
  • Acknowledge the receipt of the callback.

For detailed step-by-step instructions on implementing callback handling, refer to the Guides: Callbacks article in the Guides section. It provides comprehensive guidance on setting up and implementing callbacks in your integration.

Acknowledging callback receipt

When your system receives a callback from IXOPAY platform, it is essential to acknowledge the receipt of the notification by responding with an HTTP status code 200 and a response body of OK:

HTTP/1.1 200 OK
Content-Type: text/plain; charset=UTF-8


The initial callback from IXOPAY has a timeout of 10 seconds, which means your system's response should not take longer than this. Subsequent callbacks have a timeout of 30 seconds. Please note that these timeout durations might change in the future, and this page will be updated if that happens.

If your system does not provide a confirmation response with an HTTP status code 200 and content OK, IXOPAY will continue to retry sending the notification at increasing intervals according to the following schedule:

Retry NumberInterval
First retry1 minute
Second retry5 minutes
Third retry15 minutes
Fourth retry1 hour
Fifth retry2 hours
Sixth retry3 hours
Seventh retry12 hours
Final retryOnce every 24 hours for 7 days

During these retries, IXOPAY platform will continue attempting to send the notification to your callback endpoint. It is important to ensure that your system responds with the appropriate status code and content to acknowledge the receipt of the notification and avoid any potential delays or duplicate notifications.

Signature verification

The IXOPAY platform signs every callback request it sends to the merchant, providing an additional layer of security and ensuring the authenticity of the data. While signature verification is optional, it is highly recommended to verify the signature for enhanced security.

To verify the signature of a callback request, follow these steps:

  1. Compute the signature on your system using the provided shared secret and the appropriate hashing algorithm.
  2. Compare the computed signature with the signature included in the callback request.
  3. If the signatures match, you can trust the authenticity of the data.

For more detailed instructions on how to compute and validate signatures, refer to the Guides: Additional security article. The article provides comprehensive information on signature computation, validation, and other security measures you can implement.

Notification delivery times

Upon reaching a final status (either successful or erroneous), the IXOPAY platform promptly sends a notification to the callback URL specified in the transaction request. However, delivery times for these notifications may vary depending on the payment method used. In some cases, the notification may be instantaneous, while in others, it may take several days.

Processing callback data

The callback data received from the IXOPAY platform contains important information about the transaction's status and other relevant details. Ensure that your system processes this data according to your business logic.

Refer to the Callback Data article for detailed information on the structure of callback data, including how to include additional data and verify its authenticity.