Start a Callback with voximplant.callback.start

If you are developing integrations for Bitrix24 using AI tools (Codex, Claude Code, Cursor), connect to the MCP server so that the assistant can utilize the official REST documentation.

Scope: telephony

Who can execute the method: user with Outgoing Call — Execute permission

The method voximplant.callback.start initiates a callback between an employee and a client.

Method Parameters

Required parameters are marked with *

Name `type`	Description
FROM_LINE* `string`	Identifier of the outgoing line from which the callback is initiated. A list of available lines can be obtained using the voximplant.line.get method.
TO_NUMBER* `string`	The client's number to call.
TEXT_TO_PRONOUNCE* `string`	The text that the system will pronounce to the employee before connecting with the client.
VOICE `string`	Identifier of the voice for speech synthesis. If not provided, the default voice for the account's language will be used. A list of available voices can be obtained using the voximplant.tts.voices.get method.

Code Examples

How to Use Examples in Documentation

cURL (Webhook)

cURL (OAuth)

PHP

BX24.js

PHP CRest

curl -X POST \
        -H "Content-Type: application/json" \
        -H "Accept: application/json" \
        -d '{"FROM_LINE":"reg151083","TO_NUMBER":"+19991234567","TEXT_TO_PRONOUNCE":"You have received a callback request","VOICE":"internalfemale"}' \
        https://**put_your_bitrix24_address**/rest/**put_your_user_id_here**/**put_your_webhook_here**/voximplant.callback.start

curl -X POST \
        -H "Content-Type: application/json" \
        -H "Accept: application/json" \
        -d '{"FROM_LINE":"reg151083","TO_NUMBER":"+19991234567","TEXT_TO_PRONOUNCE":"You have received a callback request","VOICE":"internalfemale","auth":"**put_access_token_here**"}' \
        https://**put_your_bitrix24_address**/rest/voximplant.callback.start

try
        {
            const response = await $b24.callMethod(
                'voximplant.callback.start',
                {
                    FROM_LINE: 'reg151083',
                    TO_NUMBER: '+19991234567',
                    TEXT_TO_PRONOUNCE: 'You have received a callback request',
                    VOICE: 'internalfemale'
                }
            );
        
            const result = response.getData().result;
            console.log('Data:', result);
        }
        catch (error)
        {
            console.error('Error:', error);
        }

try {
            $response = $b24Service
                ->core
                ->call(
                    'voximplant.callback.start',
                    [
                        'FROM_LINE' => 'reg151083',
                        'TO_NUMBER' => '+19991234567',
                        'TEXT_TO_PRONOUNCE' => 'You have received a callback request',
                        'VOICE' => 'internalfemale',
                    ]
                );
        
            $result = $response
                ->getResponseData()
                ->getResult();
        
            echo 'Success: ' . print_r($result, true);
        } catch (Throwable $e) {
            error_log($e->getMessage());
            echo 'Error: ' . $e->getMessage();
        }

BX24.callMethod(
            'voximplant.callback.start',
            {
                FROM_LINE: 'reg151083',
                TO_NUMBER: '+19991234567',
                TEXT_TO_PRONOUNCE: 'You have received a callback request',
                VOICE: 'internalfemale'
            },
            function(result)
            {
                if (result.error())
                {
                    console.error(result.error(), result.error_description());
                }
                else
                {
                    console.log(result.data());
                }
            }
        );

require_once('crest.php');
        
        $result = CRest::call(
            'voximplant.callback.start',
            [
                'FROM_LINE' => 'reg151083',
                'TO_NUMBER' => '+19991234567',
                'TEXT_TO_PRONOUNCE' => 'You have received a callback request',
                'VOICE' => 'internalfemale',
            ]
        );
        
        echo '<PRE>';
        print_r($result);
        echo '</PRE>';

Response Handling

HTTP Status: 200

{
            "result": {
                "RESULT": true,
                "CALL_ID": "callback.72f42b118e019a4cc47629ff60525f43.1773736077"
            },
            "time": {
                "start": 1773736066,
                "finish": 1773736067.708955,
                "duration": 1.7089550495147705,
                "processing": 1,
                "date_start": "2026-03-17T11:27:46+02:00",
                "date_finish": "2026-03-17T11:27:47+02:00",
                "operating_reset_at": 1773736666,
                "operating": 0.9574570655822754
            }
        }

Returned Data

Name `type`	Description
result `object`	Object containing the result of the callback initiation.
RESULT `boolean`	Indicator of successful initiation. `true` — callback successfully initiated.
CALL_ID `string`	Identifier of the call.
time `time`	Information about the request execution time.

Error Handling

HTTP Status: 400, 403

{
            "error": "ERROR_CORE",
            "error_description": "Could not find line reg000000"
        }

Name `type`	Description
error `string`	String error code. It may consist of digits, Latin letters, and underscores
error_description `error_description`	Textual description of the error. The description is not intended to be shown to the end user in its raw form

Possible Error Codes

Code	Description	Value
`ERROR_CORE`	`Could not find line <LINE_ID>`	The line with the specified identifier was not found.
`ERROR_CORE`	`Could not find config for number <LINE_ID>`	Configuration for the specified line was not found.
`ERROR_CORE`	`Phone number is not correct`	Incorrect number in `TO_NUMBER`.
`ACCESS_DENIED`	`Access denied`	Insufficient permissions to make outgoing calls.

Statuses and System Error Codes

HTTP Status: 20x, 40x, 50x

The errors described below may occur when calling any method.

Status	Code Error Message	Description
`500`	`INTERNAL_SERVER_ERROR` Internal server error	An internal server error has occurred. Please contact the server administrator or Bitrix24 technical support
`500`	`ERROR_UNEXPECTED_ANSWER` Server returned an unexpected response	An internal server error has occurred. Please contact the server administrator or Bitrix24 technical support
`503`	`QUERY_LIMIT_EXCEEDED` Too many requests	The request intensity limit has been exceeded
`405`	`ERROR_BATCH_METHOD_NOT_ALLOWED` Method is not allowed for batch usage	The current method is not permitted for calls using batch
`400`	`ERROR_BATCH_LENGTH_EXCEEDED` Max batch length exceeded	The maximum length of parameters passed to the batch method has been exceeded
`401`	`NO_AUTH_FOUND` Wrong authorization data	Invalid access token or webhook code
`400`	`INVALID_REQUEST` Https required	The HTTPS protocol is required for method calls
`503`	`OVERLOAD_LIMIT` REST API is blocked due to overload	The REST API is blocked due to overload. This is a manual individual block; please contact Bitrix24 technical support to lift it
`403`	`ACCESS_DENIED` REST API is available only on commercial plans	The REST API is only available on commercial plans
`403`	`INVALID_CREDENTIALS` Invalid request credentials	The user associated with the access token or webhook used to call the method lacks the necessary permissions
`404`	`ERROR_MANIFEST_IS_NOT_AVAILABLE` Manifest is not available	The manifest is not available
`403`	`insufficient_scope` The request requires higher privileges than provided by the webhook token	The request requires higher privileges than those provided by the webhook token
`401`	`expired_token` The access token provided has expired	The provided access token has expired
`403`	`user_access_error` The user does not have access to the application	The user does not have access to the application. This means that the application is installed, but the portal administrator has restricted access to this application to specific users only
`500`	`PORTAL_DELETED` Portal was deleted	The public part of the site is closed. To open the public part of the site on an on-premise installation, disable the "Temporary closure of the public part of the site" option. Path to the setting: Desktop > Settings > Product Settings > Module Settings > Main Module > Temporary closure of the public part of the site

Continue Learning

Overview of Methods

Make an Auto-Call with MP3 Playback

Start a Callback with voximplant.callback.start

Method ParametersMethod Parameters

Code ExamplesCode Examples

Response HandlingResponse Handling

Returned DataReturned Data

Error HandlingError Handling

Possible Error CodesPossible Error Codes

Statuses and System Error CodesStatuses and System Error Codes

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