This may help you to find out which mobile carrier supports SMS A2P 10-DLC.

https://www.openmarket.com/blog/what-is-a2p-10-dlc/

Thanks Phong. That is what I am referring too. Seems to me until Sprint completes rollout sending A2P 10DLC via RC's "commercial long code" support may fail. There is potential here to have a number blocked I think. That is my concern.

We don't have a way to query which carrier supports A2P SMS 10-DLC or not. We don't verify which mobile carrier's number when we send A2P SMS. But we do return error codes which can be used to identify the failure reason. See this error code list and pay attention to the SMS-CAR-XXX code.

Thank you.

I do not want to get errors, that is why I am asking the question.

We are migrating our P2P SMS system (currently using a different provider) to A2P with 10DLC. Our numbers for this have just been provisioned by RC with A2PSMS permission.

Are my SMSs to people in the Sprint network going to fail right now? Even if they don't fail, do I risk my A2PSMS numbers being blocked because Sprint is not yet support this?

I am not sure if Sprint allows A2P SMS from Toll Free number. If they supports, then use the TF SMS number instead. If not, find someway to identify the Sprint recipient numbers to avoid sending text message to those numbers.