Create call

Important

APIs under the /beta version in Microsoft Graph are subject to change. Use of these APIs in production applications is not supported.

Create call enables your bot to create a new outgoing call or join an existing meeting. You will need to register the calling bot and go through the list of permissions needed as mentioned below.

Permissions

One of the following permissions is required to call this API. To learn more, including how to choose permissions, see Permissions.

Permission type Permissions (from least to most privileged)
Delegated (work or school account) Not Supported
Delegated (personal Microsoft account) Not Supported
Application Calls.JoinGroupCallsasGuest.All, Calls.JoinGroupCalls.All, Calls.Initiate.All, Calls.InitiateGroupCalls.All

Note: In addition, for a call with app hosted media, you need the Calls.AccessMedia.All permission.

HTTP request

POST /app/calls

Request headers

Name Description
Authorization Bearer {token}. Required.

Request body

In the request body, supply a JSON representation of a call object.

Note: Properties marked as Server generated are ignored when processing POST on app/calls.

Response

If successful, this method returns a 201 Created response code and a call object in the response body.

Examples

Create peer to peer VOIP call with service hosted media

Note: This call needs the Calls.Initiate.All permission.

Request

The following example shows the request which makes a peer to peer call between the bot and the specified user. In this example the media is hosted by the service. The values of authorization token, callback url, application id, application name, user id, user name and tenant id must be replaced with actual values to make the example work.

POST https://graph.microsoft.com/beta/app/calls
Content-Type: application/json
Authorization: Bearer <Token>

{
  "@odata.type": "#microsoft.graph.call",
  "callbackUri": "https://bot.contoso.com/callback",
  "targets": [
    {
      "@odata.type": "#microsoft.graph.participantInfo",
      "identity": {
        "@odata.type": "#microsoft.graph.identitySet",
        "user": {
          "@odata.type": "#microsoft.graph.identity",
          "displayName": "John",
          "id": "112f7296-5fa4-42ca-bae8-6a692b15d4b8"
        }
      }
    }
  ],
  "requestedModalities": [
    "audio"
  ],
  "mediaConfig": {
    "@odata.type": "#microsoft.graph.serviceHostedMediaConfig",
  }
}
Response

Note: The response object shown here might be shortened for readability. All the properties will be returned from an actual call.

HTTP/1.1 201 Created
Location: https://graph.microsoft.com/beta/app/calls/2e1a0b00-2db4-4022-9570-243709c565ab
Content-Type: application/json


{
  "@odata.type": "#microsoft.graph.call",
  "state": "establishing",
  "direction": "outgoing",
  "callbackUri": "https://bot.contoso.com/callback",
  "callRoutes": [],
  "source": {
    "@odata.type": "#microsoft.graph.participantInfo",
    "identity": {
      "@odata.type": "#microsoft.graph.identitySet",
      "application": {
        "@odata.type": "#microsoft.graph.identity",
        "displayName": "Calling Bot",
        "id": "2891555a-92ff-42e6-80fa-6e1300c6b5c6",
      }
    },
    "region": null,
    "languageId": null
  },
  "targets": [
    {
      "@odata.type": "#microsoft.graph.participantInfo",
      "identity": {
        "@odata.type": "#microsoft.graph.identitySet",
        "user": {
          "@odata.type": "#microsoft.graph.identity",
          "displayName": "John",
          "id": "112f7296-5fa4-42ca-bae8-6a692b15d4b8"
        }
      },
      "region": null,
      "languageId": null
    }
  ],
  "requestedModalities": [
    "audio"
  ],
  "activeModalities": [],
  "mediaConfig": {
    "@odata.type": "#microsoft.graph.serviceHostedMediaConfig",
    "preFetchMedia": [
     {
       "uri": "https://cdn.contoso.com/beep.wav",
       "resourceId": "f8971b04-b53e-418c-9222-c82ce681a582"
     },
     {
       "uri": "https://cdn.contoso.com/cool.wav",
       "resourceId": "86dc814b-c172-4428-9112-60f8ecae1edb"
     }
    ],
  },
  "routingPolicies": [],
  "tenantId": "aa67bd4c-8475-432d-bd41-39f255720e0a",
  "myParticipantId": "499ff390-7a72-40e8-83a0-8fac6295ae7e",
  "id": "2e1a0b00-2db4-4022-9570-243709c565ab",
  "@odata.context": "https://graph.microsoft.com/beta/$metadata#app/calls/$entity",
  "subject": null,
  "terminationReason": null,
  "ringingTimeoutInSeconds": null,
  "mediaState": null,
  "resultInfo": null,
  "answeredBy": null,
  "chatInfo": null,
  "meetingInfo": null,
  "meetingCapability": null,
  "toneInfo": null
}
Notification - establishing
POST https://bot.contoso.com/callback
Authorization: Bearer <TOKEN>
Content-Type: application/json
{
  "@odata.type": "#microsoft.graph.commsNotifications",
  "value": [
    {
      "@odata.type": "#microsoft.graph.commsNotification",
      "changeType": "updated",
      "resource": "/app/calls/2e1a0b00-2db4-4022-9570-243709c565ab",
      "callbackUri": "https://bot.contoso.com/callback",
      "resourceData": {
        "@odata.type": "#microsoft.graph.call",
        "state": "establishing",
        "id": "2e1a0b00-2db4-4022-9570-243709c565ab"
      }
    }
  ]
}
Notification - established
POST https://bot.contoso.com/callback
Authorization: Bearer <TOKEN>
Content-Type: application/json
{
  "@odata.type": "#microsoft.graph.commsNotifications",
  "value": [
    {
      "@odata.type": "#microsoft.graph.commsNotification",
      "changeType": "updated",
      "resource": "/app/calls/2e1a0b00-b3c5-4b0f-99b3-c133bc1e6116",
      "callbackUri": "https://bot.contoso.com/callback",
      "resourceData": {
        "@odata.type": "#microsoft.graph.call",
        "state": "established",
        "direction": "outgoing",
        "tenantId": "aa67bd4c-8475-432d-bd41-39f255720e0a",
        "id": "2e1a0b00-b3c5-4b0f-99b3-c133bc1e6116"
      }
    }
  ]
}

Create peer to peer VOIP call with application hosted media

Note: Needs Calls.Initiate.All and Calls.AccessMedia.All permission.

Request

The following example shows the request which makes a peer to peer call between the bot and the specified user. In this example the media is hosted locally by the application. The values of authorization token, callback url, application id, application name, user id, user name and tenant id must be replaced with actual values to make the example work.

POST https://graph.microsoft.com/beta/app/calls
Content-Type: application/json
Authorization: Bearer <Token>
{
  "@odata.type": "#microsoft.graph.call",
  "callbackUri": "https://bot.contoso.com/callback",
  "targets": [
    {
      "@odata.type": "#microsoft.graph.participantInfo",
      "identity": {
        "@odata.type": "#microsoft.graph.identitySet",
        "user": {
          "@odata.type": "#microsoft.graph.identity",
          "displayName": "John",
          "id": "112f7296-5fa4-42ca-bae8-6a692b15d4b8"
        }
      }
    }
  ],
  "requestedModalities": [
    "audio"
  ],
 "mediaConfig": {
    "@odata.type": "#microsoft.graph.appHostedMediaConfig",
    "blob": "<Media Session Configuration>",
  }
}

<Media Session Configuration> is the serialized media session configuration which contains the session information of the media stack. Specific information about audio, video, VBSS ssession information should be passed here.

Sample audio media session blob is shown below

{\"mpUri\":\"net.tcp://bot.contoso.com:18732/MediaProcessor\",\"audioRenderContexts\":[\"14778cc4-f54c-43c7-989f-9092e34ef784\"],\"videoRenderContexts\":[],\"audioSourceContexts\":[\"a5dcfc9b-5a54-48ef-86f5-1fdd8508741a\"],\"videoSourceContexts\":[],\"dataRenderContexts\":null,\"dataSourceContexts\":null,\"supportedAudioFormat\":\"Pcm16K\",\"videoSinkEncodingFormats\":[],\"mpMediaSessionId\":\"2379cf46-acf3-4fef-a914-be9627075320\",\"regionAffinity\":null,\"skypeMediaBotsVersion\":\"1.11.1.0086\",\"mediaStackVersion\":\"2018.53.1.1\",\"mpVersion\":\"7.2.0.3881\",\"callId\":\"1b69b141-7f1a-4033-9c34-202737190a20\"}

Note: For peer to peer calls, the expected notifications are for call state changes only.

Join scheduled meeting with service hosted media

To join the scheduled meeting we will need to get the thread id, message id, organizer id and the tenant id in which the meeting is scheduled. This information can be obtained from Get Online Meetings API.

The values of authorization token, callback url, application id, application name, user id, user name and tenant id must be replaced along with the details obtained from Get Online Meetings API with actual values to make the example work.

Note: This example needs the Calls.JoinGroupCalls.All permission.

Request
POST https://graph.microsoft.com/beta/app/calls
Content-Type: application/json
Authorization: Bearer <Token>
{
  "@odata.type": "#microsoft.graph.call",
  "callbackUri": "https://bot.contoso.com/callback",
  "requestedModalities": [
    "audio"
  ],
  "mediaConfig": {
    "@odata.type": "#microsoft.graph.serviceHostedMediaConfig",
    "preFetchMedia": [
     {
       "uri": "https://cdn.contoso.com/beep.wav",
       "resourceId": "f8971b04-b53e-418c-9222-c82ce681a582"
     },
     {
       "uri": "https://cdn.contoso.com/cool.wav",
       "resourceId": "86dc814b-c172-4428-9112-60f8ecae1edb"
     }
    ],
  },
  "chatInfo": {
    "@odata.type": "#microsoft.graph.chatInfo",
    "threadId": "19:meeting_Win6Ydo4wsMijFjZS00ZGVjLTk5MGUtOTRjNWY2NmNkYTFm@thread.v2",
    "messageId": "0"
  },
  "meetingInfo": {
    "@odata.type": "#microsoft.graph.organizerMeetingInfo",
    "organizer": {
      "@odata.type": "#microsoft.graph.identitySet",
      "user": {
        "@odata.type": "#microsoft.graph.identity",
        "id": "5810cede-f3cc-42eb-b2c1-e9bd5d53ec96",
        "tenantId": "aa67bd4c-8475-432d-bd41-39f255720e0a",
        "displayName": "Bob"
      }
    },
    "allowConversationWithoutHost": true
  }
}
Response
HTTP/1.1 201 Created
Location: https://graph.microsoft.com/beta/app/calls/2f1a1100-b174-40a0-aba7-0b405e01ed92
Content-Type: application/json
{
  "@odata.type": "#microsoft.graph.call",
  "state": "establishing",
  "direction": "outgoing",
  "callbackUri": "https://bot.contoso.com/callback",
  "callRoutes": [],
  "source": {
    "@odata.type": "#microsoft.graph.participantInfo",
    "identity": {
      "@odata.type": "#microsoft.graph.identitySet",
      "application": {
        "@odata.type": "#microsoft.graph.identity",
        "displayName": "Calling Bot",
        "id": "2891555a-92ff-42e6-80fa-6e1300c6b5c6",
      }
    },
    "region": null,
    "languageId": null
  },
  "targets": [],
  "requestedModalities": [
    "audio"
  ],
  "activeModalities": [],
  "mediaConfig": {
    "@odata.type": "#microsoft.graph.serviceHostedMediaConfig",
    "preFetchMedia": [
     {
       "uri": "https://cdn.contoso.com/beep.wav",
       "resourceId": "f8971b04-b53e-418c-9222-c82ce681a582"
     },
     {
       "uri": "https://cdn.contoso.com/cool.wav",
       "resourceId": "86dc814b-c172-4428-9112-60f8ecae1edb"
     }
    ],
  },
  "chatInfo": {
    "@odata.type": "#microsoft.graph.chatInfo",
    "threadId": "19:meeting_Win6Ydo4wsMijFjZS00ZGVjLTk5MGUtOTRjNWY2NmNkYTFm@thread.v2",
    "messageId": "0",
    "replyChainMessageId": null
  },
  "meetingInfo": {
    "@odata.type": "#microsoft.graph.organizerMeetingInfo",
    "organizer": {
      "@odata.type": "#microsoft.graph.identitySet",
      "user": {
        "@odata.type": "#microsoft.graph.identity",
        "id": "5810cede-f3cc-42eb-b2c1-e9bd5d53ec96",
        "tenantId": "aa67bd4c-8475-432d-bd41-39f255720e0a",
        "displayName": "Bob"
      }
    },
    "allowConversationWithoutHost": true
  },
  "routingPolicies": [],
  "tenantId": "aa67bd4c-8475-432d-bd41-39f255720e0a",
  "myParticipantId": "05491616-385f-44a8-9974-18cc5f9933c1",
  "id": "2f1a1100-b174-40a0-aba7-0b405e01ed92",
  "@odata.context": "https://graph.microsoft.com/beta/$metadata#app/calls/$entity",
  "terminationReason": null,
  "ringingTimeoutInSeconds": null,
  "mediaState": null,
  "subject": null,
  "resultInfo": null,
  "answeredBy": null,
  "meetingCapability": null,
  "toneInfo": null
}
Notification - establishing
POST https://bot.contoso.com/callback
Authorization: Bearer <TOKEN>
Content-Type: application/json
{
  "@odata.type": "#microsoft.graph.commsNotifications",
  "value": [
    {
      "@odata.type": "#microsoft.graph.commsNotification",
      "changeType": "updated",
      "resource": "/app/calls/2f1a1100-b174-40a0-aba7-0b405e01ed92",
        "callbackUri": "https://bot.contoso.com/callback",
      "resourceData": {
        "@odata.type": "#microsoft.graph.call",
        "state": "establishing",
        "chatInfo": {
          "@odata.type": "#microsoft.graph.chatInfo",
          "threadId": "19:meeting_Win6Ydo4wsMijFjZS00ZGVjLTk5MGUtOTRjNWY2NmNkYTFm@thread.v2",
          "messageId": "0"
        },
        "meetingInfo": {
          "@odata.type": "#microsoft.graph.organizerMeetingInfo",
          "organizer": {
            "@odata.type": "#microsoft.graph.identitySet",
            "user": {
              "@odata.type": "#microsoft.graph.identity",
              "id": "5810cede-f3cc-42eb-b2c1-e9bd5d53ec96",
              "tenantId": "aa67bd4c-8475-432d-bd41-39f255720e0a",
              "displayName": "Bob"
            }
          },
          "allowConversationWithoutHost": true
        },
        "id": "2f1a1100-b174-40a0-aba7-0b405e01ed92"
      }
    }
  ]
}

Notification - established
POST https://bot.contoso.com/callback
Authorization: Bearer <TOKEN>
Content-Type: application/json
{
  "@odata.type": "#microsoft.graph.commsNotifications",
  "value": [
    {
      "@odata.type": "#microsoft.graph.commsNotification",
      "changeType": "updated",
      "resource": "/app/calls/2f1a1100-b174-40a0-aba7-0b405e01ed92",
      "callbackUri": "https://bot.contoso.com/callback",
      "resourceData": {
        "@odata.type": "#microsoft.graph.call",
        "state": "established",
        "chatInfo": {
          "@odata.type": "#microsoft.graph.chatInfo",
          "threadId": "19:meeting_Win6Ydo4wsMijFjZS00ZGVjLTk5MGUtOTRjNWY2NmNkYTFm@thread.v2",
          "messageId": "0"
        },
        "meetingInfo": {
          "@odata.type": "#microsoft.graph.organizerMeetingInfo",
          "organizer": {
            "@odata.type": "#microsoft.graph.identitySet",
            "user": {
              "@odata.type": "#microsoft.graph.identity",
              "id": "5810cede-f3cc-42eb-b2c1-e9bd5d53ec96",
              "tenantId": "aa67bd4c-8475-432d-bd41-39f255720e0a",
              "displayName": "Bob"
            }
          },
          "allowConversationWithoutHost": true
        },
        "id": "2f1a1100-b174-40a0-aba7-0b405e01ed92"
      }
    }
  ]
}
Notification - Roster
POST https://bot.contoso.com/callback
Authorization: Bearer <TOKEN>
Content-Type: application/json
{
  "@odata.type": "#microsoft.graph.commsNotifications",
  "value": [
    {
      "@odata.type": "#microsoft.graph.commsNotification",
      "changeType": "updated",
      "resource": "/app/calls/2f1a1100-b174-40a0-aba7-0b405e01ed92/participants",
      "callbackUri": "https://bot.contoso.com/callback",
      "resourceData": [
        {
          "@odata.type": "#microsoft.graph.participant",
          "info": {
            "@odata.type": "#microsoft.graph.participantInfo",
            "identity": {
              "@odata.type": "#microsoft.graph.identitySet",
              "user": {
                "@odata.type": "#microsoft.graph.identity",
                "displayName": "John",
                "id": "112f7296-5fa4-42ca-bae8-6a692b15d4b8"
              }
            },
            "languageId": "en-US"
          },
          "mediaStreams": [
            {
              "@odata.type": "#microsoft.graph.mediaStream",
              "mediaType": "audio",
              "sourceId": "1",
              "direction": "sendReceive",
              "serverMuted": false
            },
            {
              "@odata.type": "#microsoft.graph.mediaStream",
              "mediaType": "video",
              "sourceId": "2",
              "direction": "receiveOnly",
              "serverMuted": false
            },
            {
              "@odata.type": "#microsoft.graph.mediaStream",
              "mediaType": "videoBasedScreenSharing",
              "sourceId": "8",
              "direction": "receiveOnly",
              "serverMuted": false
            }
          ],
          "isMuted": true,
          "isInLobby": false,
          "id": "0d7664b6-6432-43ed-8d27-d9e7adec188c"
        },
        {
          "@odata.type": "#microsoft.graph.participant",
          "info": {
            "@odata.type": "#microsoft.graph.participantInfo",
            "identity": {
              "@odata.type": "#microsoft.graph.identitySet",
              "application": {
                "@odata.type": "#microsoft.graph.identity",
                "displayName": "Calling Bot",
                "id": "2891555a-92ff-42e6-80fa-6e1300c6b5c6"
              }
            }
          },
          "mediaStreams": [
            {
              "@odata.type": "#microsoft.graph.mediaStream",
              "mediaType": "audio",
              "sourceId": "10",
              "direction": "sendReceive",
              "serverMuted": false
            }
          ],
          "isMuted": false,
          "isInLobby": false,
          "id": "05491616-385f-44a8-9974-18cc5f9933c1"
        }
      ]
    }
  ]
}

Note: For join meeting scenarios apart from call state notifications, we receive roster notifications.

Join scheduled meeting with app hosted media

To join the meeting with application hosted media update the media config with the AppHostedMediaConfig as shown below, In the sample provided above.

POST https://graph.microsoft.com/beta/app/calls
Content-Type: application/json
Authorization: Bearer <Token>
{
  "@odata.type": "#microsoft.graph.call",
  "direction": "outgoing",
  "callbackUri": "https://bot.contoso.com/callback",
  "requestedModalities": [
    "audio"
  ],
  "mediaConfig": {
    "@odata.type": "#microsoft.graph.appHostedMediaConfig",
    "blob": "<Media Session Configuration>",
  },
  "chatInfo": {
    "@odata.type": "#microsoft.graph.chatInfo",
    "threadId": "19:meeting_Win6Ydo4wsMijFjZS00ZGVjLTk5MGUtOTRjNWY2NmNkYTFm@thread.v2",
    "messageId": "0"
  },
  "meetingInfo": {
    "@odata.type": "#microsoft.graph.organizerMeetingInfo",
    "organizer": {
      "@odata.type": "#microsoft.graph.identitySet",
      "user": {
        "@odata.type": "#microsoft.graph.identity",
        "id": "5810cede-f3cc-42eb-b2c1-e9bd5d53ec96",
        "tenantId": "aa67bd4c-8475-432d-bd41-39f255720e0a",
        "displayName": "Bob"
      }
    },
    "allowConversationWithoutHost": true
  },
  "tenantId": "aa67bd4c-8475-432d-bd41-39f255720e0a"
}

Join channel meeting with service hosted media

Meeting inside a channel requires specific details like thread id, messageid, and organizer details that can be obtained using the Get Online Meetings API.

The values of authorization token, callback url, application id, application name, user id, user name and tenant id must be replaced along with the details obtained from Get Online Meetings API with actual values to make the example work.

Note: This example needs the Calls.JoinGroupCalls.All permission.

Request
POST https://graph.microsoft.com/beta/app/calls
Content-Type: application/json
Authorization: Bearer <Token>
{
  "@odata.type": "#microsoft.graph.call",
  "callbackUri": "https://bot.contoso.com/callback",
  "requestedModalities": [
    "audio"
  ],
  "mediaConfig": {
    "@odata.type": "#microsoft.graph.serviceHostedMediaConfig",
    "preFetchMedia": [
     {
       "uri": "https://cdn.contoso.com/beep.wav",
       "resourceId": "f8971b04-b53e-418c-9222-c82ce681a582"
     },
     {
       "uri": "https://cdn.contoso.com/cool.wav",
       "resourceId": "86dc814b-c172-4428-9112-60f8ecae1edb"
     }
    ],
  },
  "chatInfo": {
    "@odata.type": "#microsoft.graph.chatInfo",
    "threadId": "19:cbee7c1c860e465f8258e3cebf7bee0d@thread.skype",
    "messageId": "1533758867081"
  },
  "meetingInfo": {
    "@odata.type": "#microsoft.graph.organizerMeetingInfo",
    "organizer": {
      "@odata.type": "#microsoft.graph.identitySet",
      "user": {
        "@odata.type": "#microsoft.graph.identity",
        "id": "5810cede-f3cc-42eb-b2c1-e9bd5d53ec96",
        "tenantId": "aa67bd4c-8475-432d-bd41-39f255720e0a",
        "displayName": "Bob"
      }
    },
    "allowConversationWithoutHost": true
  }
}

Join channel meeting as a guest with service hosted media

For joining a channel meeting as a guest you will need to create a guest identity and add it as the call source in the join meeting request. The display name is the name you want to be displayed in the meeting for your guest identity. The id may be a unique id identifying the guest identity.

Note: This example needs the Calls.JoinGroupCallsAsGuest.All permission.

Request
POST https://graph.microsoft.com/beta/app/calls
Content-Type: application/json
Authorization: Bearer <Token>
{
  "@odata.type": "#microsoft.graph.call",
  "callbackUri": "https://bot.contoso.com/callback",
  "source": {
    "@odata.type": "#microsoft.graph.participantInfo",
    "identity": {
      "@odata.type": "#microsoft.graph.identitySet",
      "guest": {
        "@odata.type": "#microsoft.graph.identity",
        "displayName": "Guest User",
        "id": "d7a3b999-17ac-4bca-9e77-e6a730d2ec2e"
      }
    }
  },
  "requestedModalities": [
    "audio"
  ],
  "mediaConfig": {
    "@odata.type": "#microsoft.graph.serviceHostedMediaConfig",
    "preFetchMedia": [
     {
       "uri": "https://cdn.contoso.com/beep.wav",
       "resourceId": "f8971b04-b53e-418c-9222-c82ce681a582"
     },
     {
       "uri": "https://cdn.contoso.com/cool.wav",
       "resourceId": "86dc814b-c172-4428-9112-60f8ecae1edb"
     }
    ],
  },
  "chatInfo": {
    "@odata.type": "#microsoft.graph.chatInfo",
    "threadId": "19:cbee7c1c860e465f8258e3cebf7bee0d@thread.skype",
    "messageId": "1533758867081"
  },
  "meetingInfo": {
    "@odata.type": "#microsoft.graph.organizerMeetingInfo",
    "organizer": {
      "@odata.type": "#microsoft.graph.identitySet",
      "user": {
        "@odata.type": "#microsoft.graph.identity",
        "id": "5810cede-f3cc-42eb-b2c1-e9bd5d53ec96",
        "tenantId": "aa67bd4c-8475-432d-bd41-39f255720e0a",
        "displayName": "Bob"
      }
    },
    "allowConversationWithoutHost": true
  }
}

Note: The guest join depends on the tenant settings for meeting. The application might be put in lobby waiting to be admitted by a user. This is defined by the isInLobby property

Notification - Roster
POST https://bot.contoso.com/callback
Authorization: Bearer <TOKEN>
Content-Type: application/json
{
  "@odata.type": "#microsoft.graph.commsNotifications",
  "value": [
    {
      "@odata.type": "#microsoft.graph.commsNotification",
      "changeType": "updated",
      "resource": "/app/calls/2f1a1100-726f-4705-a071-30fb8f6b568f/participants",
      "callbackUri": "https://bot.contoso.com/callback",
      "resourceData": [
        {
          "@odata.type": "#microsoft.graph.participant",
          "info": {
            "@odata.type": "#microsoft.graph.participantInfo",
            "identity": {
              "@odata.type": "#microsoft.graph.identitySet",
              "guest": {
                "@odata.type": "#microsoft.graph.identity",
                "displayName": "Guest User",
                "id": "d7a3b999-17ac-4bca-9e77-e6a730d2ec2e"
              }
            }
          },
          "mediaStreams": [
            {
              "@odata.type": "#microsoft.graph.mediaStream",
              "mediaType": "audio",
              "sourceId": "10",
              "direction": "sendReceive",
              "serverMuted": false
            }
          ],
          "isMuted": false,
          "isInLobby": true,
          "id": "05491616-385f-44a8-9974-18cc5f9933c1"
        }
      ]
    }
  ]
}

Note: The application will not receive the roster for participants in the meeting until its admitted from lobby