Outbound Call API
The make call API allows you to utilize your virtual assistant to triggers an outgoing call to any PSTN number
For the launch of the outbound call to work, make sure you have published your agent and that it has a phone number attached to it.
Are you using postman?
When using curly braces in the query parameters, make sure you encode the content of your curly braces. If sent without the encoding, your request will return empty.

How to prepare your Outbound Call Query

Endpoint (mandatory)

For Agents deployed in EU region --> https://studio-api-eu.ai.vonage.com/telephony/make-call
For Agents deployed in US region --> https://studio-api-us.ai.vonage.com/telephony/make-call

Method (mandatory)

POST

Headers (mandatory)

X-Vgai-Key (Don't forget to add the value of the Vgai key after you generated it)
You can find the X-Vgai-Key on the top right of your canvas. Click on the "user" icon, and then "Generate API Key".

Body (mandatory)

Destination Parameters (mandatory)

parameter
value
to
phone number of the callee
agent id
ID of the virtual agent
from
phone number of the virtual assistant
{
"from": "string",
"agent_id": "string",
"to": "string"
}
You can choose to either usefrom or agent_id to send your request.
If you choose to use from, the request will try to get the agent connected to the number you added as the value and create a phone call from this number.
If didn’t succeed we will get an error Phone X is not attached to any agent or published version
If you choose to send agent_id , it will create a phone call from the published number of the agent.
If you try to send both, it will create a phone call based on the from number. If the number is not the published number of the agent, it will create a phone call with No Caller ID.

status_url (optional)

If the recipient cannot pick up the call for any reason, we will send a response to a designated callback URL
Add the relevant endpoint that a response is sent to in case the callee didn't manage to pick up the call.
Example Response payload:
{
"from": "972337287459",
"to": "972542233016",
"conversation_uuid": "CON-4ee2e523-4ee13-4e98-ae94-e6e3e1ab9ac6",
"status": "busy",
"timestamp": "2022-05-31T06:40:45.475Z"
}

hangup_on_answer_machine (optional)

We are able to recognize when an answering machine picks up the call and the call is going to be immediately disconnected.
Add the following parameters to your request:
parameter
value
hangup_on_answer_machine
false

session_parameters (optional)

You can send parameters to the virtual agent prior to initiating the call, e.g. the name of the caller. The agent can then greet the caller with his name.
parameter
value
CALLER_NAME
Diane Miller
"session_parameters": [
{
"name": "CALLER_NAME",
"value": "Diane Miller"
}
],

Example Query

Please make sure to change the body tag to JSON.
{
"status_url": "string",
"hangup_on_answer_machine": false,
"session_parameters": [
{
"name": "string",
"value": "string"
}
],
"from": "string",
"to": "string",
"agent_id": "string",
}

Successful Call Response

Curl Example Request

curl --location --request POST 'https://stairway.ai.vonage.com/telephony/make-call' \
--header 'X-Vgai-Key: Cuub4r22PXb0zYzJ2dt82KUZLKjo0z7' \
--header 'Content-Type: application/json' \
--data-raw '{
"from": "4420382243509",
"agent_id": "60c09d70e6a68858f4220848",
"to": "9725411116037",
"hangup_on_answer_machine": false,
"session_parameters":[
{
"name": "PROPERTY_VALUE",
"value": "500"
}
]
}'

Response

{
"session_id": "5a61cc84-4c89-4ef9-a983-5349c7112fdb",
"session_start_time": "2020-10-14T09:42:07.151657"
}

Potential Errors

Agent doesn't exist

{
"status": 404,
"message": "Version information for number AGENT_NUMBER doesn't exist"
}

Bad number format

{
"status": 400,
"message": "Bad destination number format"
}

Not Authorised

{
"status": 401,
"message": "Not Authorised"
}

The preconfigured session doesn't exist

{
"status": 500,
"message": "Failed to fetch preconfigured session information"
}
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On this page
How to prepare your Outbound Call Query
Endpoint (mandatory)
Method (mandatory)
Headers (mandatory)
Body (mandatory)
Example Query
Successful Call Response
Potential Errors