" CTIA guidelines require that these numbers not send to more than 200 unique numbers per day, no more than 1,000 messages per day, and that messages are responded to by the receivers.
Toll-free numbers may be used for application-to-person usage, including commercial and marketing use cases. There is no daily limit to toll-free SMS beyond the API rate limit, however you are still required to ensure compliance with the CTIA commercial SMS guidelines. "
ref:- https://ringcentral-faq.readthedocs.io/en/latest/sms/
Please read this blog to find out the limits and restrictions of sending SMS messages. If you need to broadcast SMS messages, the only option is to use a Toll Free SMS number. To get a Toll Free SMS number, please contact your RingCentral account manager to get it setup.
We have a public Toll Free SMS app for ad-hoc users. Once you have a toll free SMS number, feel free to try or use it. Remember that this app uses the /sms API, which has API rate limit so you can send max 40 messages per minute.
In addition, we are introducing a new API for High Volume A2P SMS (to be used with Toll Free SMS numbers and 10-DLC numbers), which can handle massive throughput (up to 250,000 message a day). If you are interested and want to have early access, please send a request via this form.