Make Voice AI Call API

POST

call

cURL

curl --request POST \
  --url https://api.bolna.ai/call \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "agent_id": "123e4567-e89b-12d3-a456-426655440000",
  "recipient_phone_number": "+10123456789",
  "from_phone_number": "+19876543007",
  "scheduled_at": "2025-08-21T10:35:00+00:00",
  "user_data": {
    "variable1": "value1",
    "variable2": "value2",
    "variable3": "some phrase as value"
  },
  "agent_data": {
    "voice_id": "Sam"
  }
}
'

import requests

url = "https://api.bolna.ai/call"

payload = {
    "agent_id": "123e4567-e89b-12d3-a456-426655440000",
    "recipient_phone_number": "+10123456789",
    "from_phone_number": "+19876543007",
    "scheduled_at": "2025-08-21T10:35:00+00:00",
    "user_data": {
        "variable1": "value1",
        "variable2": "value2",
        "variable3": "some phrase as value"
    },
    "agent_data": { "voice_id": "Sam" }
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    agent_id: '123e4567-e89b-12d3-a456-426655440000',
    recipient_phone_number: '+10123456789',
    from_phone_number: '+19876543007',
    scheduled_at: '2025-08-21T10:35:00+00:00',
    user_data: {variable1: 'value1', variable2: 'value2', variable3: 'some phrase as value'},
    agent_data: {voice_id: 'Sam'}
  })
};

fetch('https://api.bolna.ai/call', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.bolna.ai/call",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'agent_id' => '123e4567-e89b-12d3-a456-426655440000',
    'recipient_phone_number' => '+10123456789',
    'from_phone_number' => '+19876543007',
    'scheduled_at' => '2025-08-21T10:35:00+00:00',
    'user_data' => [
        'variable1' => 'value1',
        'variable2' => 'value2',
        'variable3' => 'some phrase as value'
    ],
    'agent_data' => [
        'voice_id' => 'Sam'
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.bolna.ai/call"

	payload := strings.NewReader("{\n  \"agent_id\": \"123e4567-e89b-12d3-a456-426655440000\",\n  \"recipient_phone_number\": \"+10123456789\",\n  \"from_phone_number\": \"+19876543007\",\n  \"scheduled_at\": \"2025-08-21T10:35:00+00:00\",\n  \"user_data\": {\n    \"variable1\": \"value1\",\n    \"variable2\": \"value2\",\n    \"variable3\": \"some phrase as value\"\n  },\n  \"agent_data\": {\n    \"voice_id\": \"Sam\"\n  }\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.bolna.ai/call")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"agent_id\": \"123e4567-e89b-12d3-a456-426655440000\",\n  \"recipient_phone_number\": \"+10123456789\",\n  \"from_phone_number\": \"+19876543007\",\n  \"scheduled_at\": \"2025-08-21T10:35:00+00:00\",\n  \"user_data\": {\n    \"variable1\": \"value1\",\n    \"variable2\": \"value2\",\n    \"variable3\": \"some phrase as value\"\n  },\n  \"agent_data\": {\n    \"voice_id\": \"Sam\"\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.bolna.ai/call")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"agent_id\": \"123e4567-e89b-12d3-a456-426655440000\",\n  \"recipient_phone_number\": \"+10123456789\",\n  \"from_phone_number\": \"+19876543007\",\n  \"scheduled_at\": \"2025-08-21T10:35:00+00:00\",\n  \"user_data\": {\n    \"variable1\": \"value1\",\n    \"variable2\": \"value2\",\n    \"variable3\": \"some phrase as value\"\n  },\n  \"agent_data\": {\n    \"voice_id\": \"Sam\"\n  }\n}"

response = http.request(request)
puts response.read_body

{
  "message": "done",
  "status": "queued",
  "execution_id": "123e4567-e89b-12d3-a456-426614174000"
}

{
  "error": 123,
  "message": "<string>"
}

Places an outbound call from a Bolna agent to a phone number. Returns an execution_id you use to track and retrieve the call result.

Minimal example

Only two fields are required — agent_id and recipient_phone_number. Omit from_phone_number to use your account’s default number.

Minimal request

{
  "agent_id": "123e4567-e89b-12d3-a456-426655440000",
  "recipient_phone_number": "+919876543210"
}

Response

{
  "message": "done",
  "status": "queued",
  "execution_id": "b7140255-af33-4608-8e97-04dd944b8e48"
}

Realistic example with personalization

Pass user_data to inject variables into your agent’s prompt and welcome message (e.g. {customer_name} in the prompt becomes “Asha”):

Request with personalization

{
  "agent_id": "123e4567-e89b-12d3-a456-426655440000",
  "recipient_phone_number": "+919876543210",
  "from_phone_number": "+918035739222",
  "user_data": {
    "customer_name": "Asha",
    "appointment_day": "Friday"
  }
}

Tracking the call

Use the returned execution_id to poll GET /executions/{execution_id} for status. The call goes through these stages:

queued → initiated → ringing → in-progress → call-disconnected → completed

Wait for completed, not call-disconnected. The call-disconnected event fires the instant the line drops, but conversation_duration, total_cost, recording_url, and extracted_data are not yet populated. The completed event (a few seconds later) has all finalized fields. See Get Execution.

Common 400 errors

Message	Fix
`agent_id is required`	Include a valid UUID `agent_id`
`recipient_phone_number is required`	Phone number must be E.164 format, e.g. `+919876543210`
Invalid `from_phone_number`	Must be a number purchased in your Bolna account

Authorizations

Authorization

string

header

required

Bearer authentication header of the form Bearer <token>, where <token> is your auth token.

Body

application/json

Make a phone call from agent

agent_id

string<uuid>

required

Agent id which will initiate the outbound call

recipient_phone_number

string

required

Phone number of the recipient along with country code (in E.164 format)

from_phone_number

string

Phone number of the sender along with country code (in E.164 format). Optional — if omitted, Bolna uses the account's default number.

scheduled_at

string

The scheduled date and time in ISO 8601 format with time zone

Example:

"2024-06-05T16:35:00.000+05:30"

user_data

object

Additional user dynamic variables as defined in the agent prompt

agent_data

object

Agent configuration to override the default configuration. Currently, only voice_id for the same provider is supported.

retry_config

object

Configuration for auto-retry of failed calls. See auto-retry documentation for details.

Show child attributes

bypass_call_guardrails

boolean

default:false

Skip time validation checks and make call immediately regardless of agent's calling_guardrails configuration

Response

agent status response

message

string

Response message for the call initiated

Example:

"done"

status

enum<string>

Status of the call.

Available options:

queued

Example:

"queued"

execution_id

string

Unique execution_id or call_id identifier of the call.

Pattern: ^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}

Example:

"123e4567-e89b-12d3-a456-426614174000"

Stop phone callLearn how to stop a call when its status is `queued` or `scheduled` This API allows you to cancel pending calls before they are executed.

⌘I

cURL

curl --request POST \
  --url https://api.bolna.ai/call \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "agent_id": "123e4567-e89b-12d3-a456-426655440000",
  "recipient_phone_number": "+10123456789",
  "from_phone_number": "+19876543007",
  "scheduled_at": "2025-08-21T10:35:00+00:00",
  "user_data": {
    "variable1": "value1",
    "variable2": "value2",
    "variable3": "some phrase as value"
  },
  "agent_data": {
    "voice_id": "Sam"
  }
}
'

import requests

url = "https://api.bolna.ai/call"

payload = {
    "agent_id": "123e4567-e89b-12d3-a456-426655440000",
    "recipient_phone_number": "+10123456789",
    "from_phone_number": "+19876543007",
    "scheduled_at": "2025-08-21T10:35:00+00:00",
    "user_data": {
        "variable1": "value1",
        "variable2": "value2",
        "variable3": "some phrase as value"
    },
    "agent_data": { "voice_id": "Sam" }
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    agent_id: '123e4567-e89b-12d3-a456-426655440000',
    recipient_phone_number: '+10123456789',
    from_phone_number: '+19876543007',
    scheduled_at: '2025-08-21T10:35:00+00:00',
    user_data: {variable1: 'value1', variable2: 'value2', variable3: 'some phrase as value'},
    agent_data: {voice_id: 'Sam'}
  })
};

fetch('https://api.bolna.ai/call', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.bolna.ai/call",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'agent_id' => '123e4567-e89b-12d3-a456-426655440000',
    'recipient_phone_number' => '+10123456789',
    'from_phone_number' => '+19876543007',
    'scheduled_at' => '2025-08-21T10:35:00+00:00',
    'user_data' => [
        'variable1' => 'value1',
        'variable2' => 'value2',
        'variable3' => 'some phrase as value'
    ],
    'agent_data' => [
        'voice_id' => 'Sam'
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.bolna.ai/call"

	payload := strings.NewReader("{\n  \"agent_id\": \"123e4567-e89b-12d3-a456-426655440000\",\n  \"recipient_phone_number\": \"+10123456789\",\n  \"from_phone_number\": \"+19876543007\",\n  \"scheduled_at\": \"2025-08-21T10:35:00+00:00\",\n  \"user_data\": {\n    \"variable1\": \"value1\",\n    \"variable2\": \"value2\",\n    \"variable3\": \"some phrase as value\"\n  },\n  \"agent_data\": {\n    \"voice_id\": \"Sam\"\n  }\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.bolna.ai/call")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"agent_id\": \"123e4567-e89b-12d3-a456-426655440000\",\n  \"recipient_phone_number\": \"+10123456789\",\n  \"from_phone_number\": \"+19876543007\",\n  \"scheduled_at\": \"2025-08-21T10:35:00+00:00\",\n  \"user_data\": {\n    \"variable1\": \"value1\",\n    \"variable2\": \"value2\",\n    \"variable3\": \"some phrase as value\"\n  },\n  \"agent_data\": {\n    \"voice_id\": \"Sam\"\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.bolna.ai/call")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"agent_id\": \"123e4567-e89b-12d3-a456-426655440000\",\n  \"recipient_phone_number\": \"+10123456789\",\n  \"from_phone_number\": \"+19876543007\",\n  \"scheduled_at\": \"2025-08-21T10:35:00+00:00\",\n  \"user_data\": {\n    \"variable1\": \"value1\",\n    \"variable2\": \"value2\",\n    \"variable3\": \"some phrase as value\"\n  },\n  \"agent_data\": {\n    \"voice_id\": \"Sam\"\n  }\n}"

response = http.request(request)
puts response.read_body

{
  "message": "done",
  "status": "queued",
  "execution_id": "123e4567-e89b-12d3-a456-426614174000"
}

{
  "error": 123,
  "message": "<string>"
}

Overview

Agents

Calls

Executions

Batches

Inbound

Phone Numbers

Knowledgebases

Dispositions

Providers

Sub-Accounts

Voice

User

SIP Trunks (BYOT)

Violations

Legacy APIs

Make Voice AI Call API

Minimal example

Realistic example with personalization

Tracking the call

Common 400 errors

Authorizations

Body

Response

​Minimal example

​Realistic example with personalization

​Tracking the call

​Common 400 errors

Authorizations

Body

Response

Minimal example

Realistic example with personalization

Tracking the call

Common 400 errors