Rate Limit, also known as Throughput Limit, refers to the number of application-to-person (A2P) text messages you are able to send within a specific period of time based on the following factors:

• Whether or not you’ve verified your Toll-Free messaging traffic or registered your 10-digit long code (10DLC) messaging traffic. If you haven’t verified or registered, which is mandatory, you are sending messages from the person-to-person (P2P) pathway, instead A2P. The P2P pathway is designated for everyday interactions between people – the rate limit for P2P messaging is 60 messages per minute. This is plenty sufficient for the P2P use case but is extremely limiting for business, or A2P, use cases.
• Which phone carrier or Mobile Network Operator (MNO) your end user (or message recipient) is using. Verizon is monitoring rate limits by messages sent per number per minute; AT&T by messages sent per Campaign per minute. T-Mobile, on the other hand, has a daily cap, monitoring messages sent per day at the Brand level.

Rate limits were established to both prevent the carriers’ systems from being overwhelmed or bottlenecked, and protect the end user from unsolicited messages and/or SPAM.