When migrating a short code from your “old” provider to Twilio, you will need to take special precautions to prevent downtime, and ensure that you are able to send and receive messages during the migration process. The wireless carriers do not work in sync during short code migrations, so it's probable that you will experience multiple traffic migrations before the process has fully completed. Therefore, you will want to ensure that your short code application can manage this transition period by having redundant paths.

Before beginning the migration process, we recommend the following configuration:

• Receiving Messages: Your application for processing incoming messages must be configured to receive messages from both Twilio and your previous short code provider during the migration process. For more information about processing incoming messages, please see our guide Receive and Reply to SMS Messages.
• Sending Messages: Your application should be configured to send outgoing messages first through Twilio. Your previous short code provider should be enabled as a backup, where requests are re-tried with this provider when an UNDELIVERED status is returned. Some carriers do not immediately de-activate the existing provider when activating a new provider, so checking the message delivery status is necessary to prevent duplicate messages. For more information about tracking outgoing message delivery status, please see our guide Track Delivery Status of Messages.

The Twilio Short Code Operations Team will notify you when we have received word that all wireless carriers have migrated their traffic. All of your short code traffic should be successfully sent and received at this point, so you can then discontinue service with your old provider, and turn off the redundant configurations.

Note: Our goal is to ensure that your migration goes smoothly, without any unnecessary sending or deliverability issues. If your short code migration configuration cannot be set up in this way, or if you have any other questions, please contact us at shortcodes@twilio.com or contact your Account Manager to discuss how your short code should be configured.

If you would like Twilio to manage your short code lease with Neustar/CSCA, please review our short code lease transfer instructions.