Two-way SMS basics - how replies work

What is two-way SMS?

Two-way SMS means customers can reply to your messages and you can respond back.

This is useful for:

  • appointment confirmations
  • questions and follow-ups
  • simple back-and-forth conversations
  • managing opt-outs and replies in one place

When replies are supported

Whether customers can reply depends on the sender option you use.

Replies are supported when sending from:

  • a Mobile Message dedicated number (recommended for two-way messaging)

Replies are not visible in Mobile Message when sending from:

  • your own mobile numberreplies are sent back to your phone directly
  • replies will not appear in the Messenger

Replies are not supported at all when sending from:

  • a custom sender ID (business name)

Custom sender IDs are designed for one-way messaging only.

Where replies go

Inbound replies are delivered based on the sender option used.

  • Dedicated numberreplies appear in the Messenger
  • replies can also be sent to email or a webhook, depending on your settings

Your own mobile number

  • replies are delivered to your phone
  • replies do not appear in Mobile Message

Custom sender ID

  • replies are not supported

Replying back to customers

When using a dedicated number, you can:

  • view the conversation in the Messenger
  • send replies directly from the platform

Sending a reply is an outgoing SMS and uses credits like any other message.

Important reply behaviour

  • Replies are always linked to the number the original message was sent from
  • Changing sender options changes where replies are delivered
  • Certain keywords (such as STOP) are handled as opt-outs and should not be replied to

Testing two-way SMS

To test two-way messaging within Mobile Message:

  1. Send a message to your own mobile from a Mobile Message dedicated number.
  2. Reply to the message from your phone.
  3. Confirm the reply appears in the Messenger.
  4. Send a response back from the platform.

If a reply does not appear in the Messenger, the most common reasons are:

  • the message was sent from your own mobile number
  • the message was sent using a custom sender ID
  • replies are configured to be delivered elsewhere (for example, email or a webhook)