MMS Group Messaging

Group messaging enables multiple participants to exchange messages within a shared conversation. Unlike one-to-one messaging, group messaging keeps all participants aware of who else is in the conversation, allowing them to reply to the group and continue the discussion.

Group MMS is designed for small, interactive group discussions rather than broadcast or marketing use cases. It is particularly well-suited for 10DLC numbers.

When to Use MMS Group Messages

Group MMS is a good fit for scenarios where a business needs to facilitate a real-time conversation between multiple parties.

Suitable use cases include:

• A support agent coordinating with a customer and a specialist simultaneously.
• A service provider keeping a client and a field technician in the same conversation thread.
• A small team receiving and responding to a shared update.

Sending a Group Message

Group MMS is a feature of the Messages API and uses the standard endpoint and webhook interactions.

To initiate a group conversation, you send a separate message to each participant. Each message designates one group member as the primary recipient to and lists the remaining participants in the mms.participants array. This informs each recipient's device of the other members in the conversation, enabling them to reply to the group.

The participants array is placed within the mms node of the request body.

Example: Sending to a Group of Three

Message to recipient 1

{
  "message_type": "text",
  "text": "Hello from Vonage",
  "from": "11234567890",
  "to": "11234567891",
  "mms": {
    "participants": [
      "11234567892",
      "11234567893"
    ]
  },
  "channel": "mms"
}

Message to recipient 2

{
  "message_type": "text",
  "text": "Hello from Vonage",
  "from": "11234567890",
  "to": "11234567892",
  "mms": {
    "participants": [
      "11234567891",
      "11234567893"
    ]
  },
  "channel": "mms"
}

Message to recipient 3

{
  "message_type": "text",
  "text": "Hello from Vonage",
  "from": "11234567890",
  "to": "11234567893",
  "mms": {
    "participants": [
      "11234567891",
      "11234567892"
    ]
  },
  "channel": "mms"
}

Receiving Group Replies

When a participant replies to the group, the inbound message is delivered to your webhook. The webhook payload includes the mms.participants array, identifying the other members of the conversation.

Example: Inbound webhook from recipient 1

{
  "channel": "mms",
  "message_uuid": "aaaaaaaa-bbbb-4ccc-8ddd-0123456789fa",
  "from": "11234567891",
  "to": "11234567890",
  "timestamp": "2025-10-03T12:15:25Z",
  "origin": {
    "network_code": "12345"
  },
  "message_type": "text",
  "text": "Hello to the group!",
  "mms": {
    "participants": [
      "11234567892",
      "11234567893"
    ]
  }
}

Availability and Coverage

Further Information

• Understanding MMS messaging
• 10DLC Technical Details