Carrier limits

Vibes currently only supports MMS messages sent to AT&T, Verizon, T-Mobile/Metro, and U.S. Cellular devices.

Since our HTTP and SMPP APIs can only send text-based messages, we also offer an MMS Message API, which facilitates the sending of MMS messages that may include pictures, gifs, and more. Our current implementation utilizes MM7 protocol along with some additional customer header extensions to accommodate features and optimizations beyond the basic protocol.

What is MM7?

MM7 is the standard protocol used by the carriers to send and receive MMS messages. It is a SOAP-based protocol sent over HTTP.

The basic tenants of the protocol are:

  • The SubmitReq action, used to send an outgoing message (MT message) to a device
  • The DeliverReq to receive an incoming message (MO message) from a device

Our APIs use this standard and extends it with some custom headers. One of the most important variations allows for the use of Authentication in your MMS calls.


The standard MM7 specification has the user credentials Value Added Service Provider Identifier (VASPID) specified within the body of the XML document, which is not ideal from an implementation nor security perspective. This requires unmarshalling the XML body prior to authentication as well as includes credentials in the message body, risking it being accessed or exposed inadvertently.

Instead, Vibes utilizes the HTTP Basic Authorization header to authenticate submitting messages. Details are specified in the specific SubmitReq call.


Below are the MM7 Versions our service centers currently support. Since these are XML-based protocols, we have also provided links to the schema files used for each version. As you go through the documentation, you’ll see specs and sample code for both schemas.

It’s important to note that you don’t need to support both versions; instead, simply pick one and use that schema to create your interactions with Vibes.


More details regarding the many versions of MM7 can be found in Specification 23.140. Identified limitations can be found on our bug tracker.