SMS is a great way to send short messages, but it has limitations. An important limitation is that mobile carriers treat SMS as best effort, this means there is no guarantee that the message will arrive on time, if at all.
This can be a problem if the notification has to get to its recipient.
When you send a SMS that’s longer than 160 characters, the carrier will break the message up into segments, the size of the segment depends on the carrier. Each segment is transported individually and recombined by the phone into a single message.
Segments can arrive at the phone out of order and in some cases not arrive at all. When this happens there is a higher likelihood that the message will be garbled or discarded.
Shorter messages equal less segments and a higher chance the message will arrive. As a best practice we recommend keeping SMS below 450 characters.