In the last Marketing Cloud release there is the new transactional messaging API option (https://developer.salesforce.com/docs/atlas.en-us.mc-apis.meta/mc-apis/transactional-messaging-api.htm).
Before we want to enable this option we wondered what this new API call is doing exactly other then a standard normal API call. Why should we use this new API call instead of the standard (server to server) API integration? Is there someone allready use this new option?
The advantage is that you can create your definition on the API using REST, as opposed to only using SOAP... I think the data model is a bit cleaner, and the transactional SMS api is also much more similar to e-mail, which would be very helpful to developers.
Unfortunately, there is a lot of missing features as it is a very new API... We couldn't find a way to generate reports, or manage definitions through the UI.
We gave up on using it in production as of now, and we are sticking with good old "Triggered Send".