Default Behavior

If you have multiple channels of the same type connected to your account, the channel the contact most recently contacted you through is prioritized. A contact can be locked to a specific channel, so they only receive messages from that channel, when all three of these conditions are met:

1. You have multiple channels of the same type connected to your account.

2. The contact's highest-priority address type (e.g., phone number) matches the channel type you have multiple channels of (e.g., multiple phone numbers).

3. The contact initiates contact by sending an incoming message.

If the contact has never interacted with any of your account's channels, we prioritize the channel whose number shares the longest prefix with the contact's number (that is, starts most similarly).

For example, if you have one Android Relayer channel with the number +2505661212 and another with +2505551212, and you send an SMS to or call +2505661231, we use the +2505661212 channel because its number overlaps the most.

In most cases, we can also identify the carrier of a contact's phone number and prioritize channels based on carrier, though this depends on how the carrier behaves.

Custom Behavior

You can use the Set preferred channel action to assign or switch a contact's preferred channel without waiting for a response.