Create and initiate a new outbound voice call

Request

Create a new outbound call session associated to the project's default service or to the service specified in the serviceId query parameter.

Security

BasicAuth or SinchOAuth2

Path

projectIdstring, (uuid)(Project ID)required

The ID of the project.

Example:5c5bf2b1-35ae-4825-ab89-457e07bb60e6

Query

serviceIdstring, (uuid)(Service ID)

The ID of the service.

Example:serviceId=6e124178-c29d-46a5-943c-5c2ae544aade

Idempotency-Keystring, [ 16 .. 128 ] characters

Client-generated idempotency key to safely retry requests. The server uses this key to recognize retries of the same request. If a request with the same key is received within 10 minutes, the server returns the cached response from the original request. Using a random UUID (v4) is strongly recommended.

Bodyapplication/json

commandsArray of objects(SVAML Commands)required

An ordered list of SVAML v2 (Sinch Voice Application Markup Language) commands that describe a call flow. Commands are executed sequentially in the order they are defined.

Blocking vs. non-blocking: Some commands block execution until they complete (pause, webhook, menu, gotoMenu), while others return immediately and run in parallel (dial, messages, amd, answer, hangup, startRecording, stopRecording, bridgeCall, stopMessages). Each command's description specifies its behavior.

Nesting scope: Commands that appear inside event handlers (e.g., dial.events.onAnswer, messages.events.onFinish) form independent sequences and execute in their own context — they are not continuations of the parent sequence.

Nesting depth: A SVAML payload can be nested at most 128 levels deep, counting every JSON object and array from the root of the document. Each command nested inside an event handler adds three levels (the command object, its events object and the handler array), which allows roughly 40 levels of nested commands. A request that exceeds the limit is rejected with 400 Bad Request; a webhook response that exceeds it counts as a failed delivery.

curl -i -X POST \
  -u '<username>:<password>' \
  'https://voice.api.sinch.com/v2/projects/{projectId}/calls' \
  -H 'Content-Type: application/json' \
  -d '{
    "commands": [
      {
        "command": "dial",
        "callName": "origin",
        "from": {
          "type": "PHONE",
          "phone": {
            "number": "+15551234567"
          }
        },
        "to": {
          "type": "PHONE",
          "phone": {
            "number": "+15559876543"
          }
        },
        "dialTimeoutDurationSeconds": 30,
        "maxCallDurationSeconds": 3600,
        "events": {
          "onAnswer": [
            {
              "command": "messages",
              "messages": [
                {
                  "type": "SAY",
                  "say": {
                    "text": "Hello, your call is now connected.",
                    "voiceName": "Emma_3"
                  }
                }
              ]
            }
          ],
          "onHangup": [
            {
              "command": "hangup"
            }
          ]
        }
      }
    ]
  }'

Responses

Call created

Bodyapplication/json

projectIdstring, (uuid)(Project ID)required

The Id of the project associated with the call.

Example:"5c5bf2b1-35ae-4825-ab89-457e07bb60e6"

serviceIdstring, (uuid)(Service ID)required

The ID of the service used.

Example:"6e124178-c29d-46a5-943c-5c2ae544aade"

sessionIdstring, (ulid)(Session ID)required

The ID of the session.

Example:"01BX5ZZKBKACTAV9WEVGEMMVRB"

Response

{
  "projectId": "5c5bf2b1-35ae-4825-ab89-457e07bb60e6",
  "serviceId": "6e124178-c29d-46a5-943c-5c2ae544aade",
  "sessionId": "01BX5ZZKBKACTAV9WEVGEMMVRB"
}