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SMS Service - HTTP Notifications

SMS Service - HTTP Notifications

Overview

Viatel supports HTTP notifications for a number of events related to your Viatel SMS service, allowing you to receive instant status updates when specific events occur. Once enabled for your SMS service, the Viatel platform will send an HTTP request to your specified endpoint. These HTTP notifications are also commonly referred to as callbacks or webhooks, and they allow your systems to automatically react to events such as message delivery updates in real time.

Enabling HTTP Notifications

To start receiving notifications for incoming SMS via HTTP, contact support@viatel.se. Please include:

  • The event that should trigger the notification. The supported events are:

  • The name of the SMS account to configure.

  • The URL where notifications should be sent.

  • E-mail address if you would like to receive an e-mail when the HTTP push is not acknowledged (a technical contact).

Once configured, Viatel will begin sending requests to the provided URL whenever the specified event occurs.

Endpoint Requirements

  • Your system must expose an HTTPS endpoint capable of receiving requests of correct format (POST).

  • Allow incoming requests from the following IP subnets: 192.121.226.0/24 and 193.235.51.0/24.

  • Your server must respond with the text OK_VIATEL_OK and HTTP Status 200 to acknowledge receipt (see Acknowledgement chapter below).

Acknowledgement

Your server must respond with HTTP status 200 and the exact plain-text string: OK_VIATEL_OK. This confirms that your system successfully received the delivery report.

⚠️ Important: You must send this acknowledgement immediately upon receipt, even if the message cannot be found or processed internally. Failing to do so will result in repeated retries and may trigger warning emails to your configured technical contact.

Retry Logic

If a valid acknowledgement is not received:

  • Viatel will retry the delivery every 10 minutes.

  • Retries continue up to a configurable maximum number of attempts (typically 10 times).

  • If a technical contact is provided, a notification email may be sent after repeated failures.

Additional Notes

  • Ensure high availability of your endpoint to avoid missed or repeated delivery attempts.

  • You can update your URL by contacting support@viatel.se.