SMS limits and restrictions - Amazon Pinpoint SMS

SMS limits and restrictions

The SMS protocol is subject to several limitations and restrictions. For example, there are technical limitations that limit the length of each SMS message. There are also restrictions on the type of content that you can send using SMS. This topic discusses several of these limitations and restrictions.

When you're setting up SMS messaging in Amazon Pinpoint SMS, you must consider these limitations and restrictions. As a best practice, you should also implement the techniques discussed in SMS best practices.

Differences between message type and message routes

Messages sent through Amazon Pinpoint SMS can either be promotional or transactional. A promotional message type is typically comprised of marketing or sales-related messages. Some countries or regions have quiet time hours when you're not permitted to send promotional messages. A transactional message type is for more time-sensitive messages, such as password resets or one-time passwords.

You pass the route type as an optional parameter using the SendTextMessages operation of the Amazon Pinpoint SMS API. In some cases you might use a sender ID as the originator, or you might have a shared pool of numbers. If you have both transactional and promotional numbers associated with your account for the destination country, Amazon Pinpoint SMS chooses a transactional number by default. Delivery receipts and the Delivery dashboard show the route as either promotional or transactional, based on the chosen number.