Preventing Outbound Message Blocking


This article provides some best practices to avoid having outbound messages blocked by the receiving carriers. Carriers expect messages sent from 10 digit numbers to be person to person and not Application to Person (A2P). A2P traffic is subject to blocking based upon section 6 of the CTIA Messaging Principles and Best Practices.


It is important to ensure that outbound messaging recipients have explicitly opted in to receive SMS messages for the purpose they are sent. Review our compliance considerations for additional compliance considerations.

Content Considerations

The following should be considered when drafting outbound message content:

Repetitive Content

When possible, content should be individualized for the recipient. This can be accomplished via integration of the Quiq Send Notification API into a CRM or other system that can personalize the message. If using the Outbound Notifications feature of Quiq, consider sending small batches with varied content vs. large batches of a single message.

Relevant Content

Users may simply block messages from a given number using carrier tools available via web or app, if the content they receive is not relevant. This blocking may result in a higher number of messages blocked by the carrier due to their blocking algorithms. Also ensure that recipients know they may reply with just the word STOP, to discontinue receiving messages. This will avoid any other reporting of the sending number.

Message Length Matters

Large message lengths are often broken into segments to facilitate delivery across carrier systems. These segments are seen as multiple messages by the carriers and inflate the message count seen from the sending number. SMS is not email, and the messages should be short and concise.

URL Inclusion

Including URL’s, especially shortened URL’s from the common URL shortening services, can lead to a higher level of suspicion by the carrier.