How does SMS fallback work for MMS?

Bhavin_Patel — Wed, 23 Jul 2025 08:52:51 GMT

Sinch converts the MMS into SMS URL for the scenarios listed below:

If MMS submitted is a greater size than the destination mobile network operator.
If the Content-type submitted is not supported by the end carrier MMSC.
If the Sinch Platform determines that the end-user device is not MMS compatible for the content to be delivered. For example, Android Devices does not support PDF and ICS file formats.

If any of these scenarios are met, the Sinch MMSC Platform sends submitted multimedia content converting into SMS URL. The client is charged only for the MMS submission portion. Proper Postback Status is returned to the Client as per the API specs when a SMS fallback event occurs.

Important Notes:

SMS Fallback only works for HTTP XML API, this functionality does not extend to MM7 API.
SMS fallback is only triggered in the case where any of the above listed criteria are met.
For carriers not supported by Sinch or where Sinch do not have MMS reach, SMS fallback does not happen.
We are able to obtain handset type information from delivery receipts and store the record in a handset cache for later use.
We have a database of attributes which we manually match to every new handset in the cache so we can adapt the content during MMS delivery.

SMS fallback is currently supported in the US (United States) on Short Codes.

Visit the Sinch MMS product page to learn more about our MMS product.

article How does SMS fallback work for MMS? in MMS

How does SMS fallback work for MMS?