Voice API

Cancel transfer

Cancels an in-progress transfer and resumes the original call when possible.

Try in API Playground ↗Sign in to prepare and run this request.

POST/api/v1/voice/call-control/transfer-cancel

Before you start

Inspect the transfer status and use the matching transfer identifiers.

Result

Read the cancellation result and check the current call state.

Charges and safe retries

Cancellation may no longer be possible after the transfer has completed.

Authentication

Send your account API key in the X-Api-Key header. Keep it on your server; never embed it in browser code.

Request examples

Replace the example values with your own inputs. Examples do not run on this page. Production requests can change your account or incur charges.

cURL

curl -X POST "https://api.illyvoip.com/api/v1/voice/call-control/transfer-cancel" \
  -H "X-Api-Key: ${ILLYVOIP_API_KEY:?Set ILLYVOIP_API_KEY}" \
  -H "Idempotency-Key: YOUR_UNIQUE_IDEMPOTENCY_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "transfer_id": "YOUR_TRANSFER_ID"
}'

Node.js

const response = await fetch("https://api.illyvoip.com/api/v1/voice/call-control/transfer-cancel", {
  method: "POST",
  headers: {
    "X-Api-Key": process.env.ILLYVOIP_API_KEY,
    "Idempotency-Key": "YOUR_UNIQUE_IDEMPOTENCY_KEY",
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    "transfer_id": "YOUR_TRANSFER_ID"
})
});

const data = await response.json();
console.log(response.status, data);

PHP

<?php
$ch = curl_init('https://api.illyvoip.com/api/v1/voice/call-control/transfer-cancel');
curl_setopt_array($ch, [
    CURLOPT_CUSTOMREQUEST => 'POST',
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => [
        'X-Api-Key: ' . getenv('ILLYVOIP_API_KEY'),
        'Idempotency-Key: YOUR_UNIQUE_IDEMPOTENCY_KEY',
        'Content-Type: application/json'
    ],
    CURLOPT_POSTFIELDS => '{
    "transfer_id": "YOUR_TRANSFER_ID"
}',
]);

$response = curl_exec($ch);
$status = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);

echo $status . PHP_EOL;
echo $response;

Python

import os
import json
import requests

response = requests.request(
    "POST",
    "https://api.illyvoip.com/api/v1/voice/call-control/transfer-cancel",
    headers={
        "X-Api-Key": os.environ["ILLYVOIP_API_KEY"],
        "Idempotency-Key": "YOUR_UNIQUE_IDEMPOTENCY_KEY",
        'Content-Type': 'application/json'
    },
    json=json.loads("{\n    \"transfer_id\": \"YOUR_TRANSFER_ID\"\n}"),
)

print(response.status_code)
print(response.json())

Node.js examples run on the server (Node.js 22.17+). Python examples require requests; PHP examples require cURL. Set the environment variables referenced in each example.

Request body

application/json

Body required.

transfer_idstringrequired

Transfer ID returned by the transfer endpoint.

Additional properties: not allowed.

Full schema

Schema

{
  "type": "object",
  "additionalProperties": false,
  "properties": {
    "transfer_id": {
      "type": "string",
      "description": "Transfer ID returned by the transfer endpoint."
    }
  },
  "required": [
    "transfer_id"
  ]
}

Example body

JSON

{
  "transfer_id": "xfer_a36f61b5370ff6d4b8396c1f2d1a89ee"
}

Request behavior

Use this while the transfer is still connecting or ringing.

Response fields

status: Request outcome. Read the resource state separately; success does not always mean delivery or completion.
transfer_id: Public reference used to check or cancel this transfer.
call_control_id: Control session reference returned by Create or Answer; use it for subsequent live actions.
transfer: Transfer state and result details.

HTTP responses

Expand a status to inspect its documented response format and examples. Example prices, IDs and timestamps are illustrative values, not quotes or account records.

200 Successful customer-facing response.

application/json

JSON

{
  "status": "success",
  "transfer_id": "xfer_a36f61b5370ff6d4b8396c1f2d1a89ee",
  "call_control_id": "vapi_760da5ee5a3c8b70777bae20fbda",
  "transfer": {
    "state": "canceled",
    "message": "Transfer canceled.",
    "target_type": "pstn",
    "target_value": "+33145512022",
    "started_at": "2026-09-07T12:00:20+00:00",
    "completed_at": null,
    "failed_at": null,
    "canceled_at": "2026-09-07T12:00:30+00:00",
    "terminal": true,
    "can_cancel": false,
    "resume_original": true
  }
}

statusstringrequired

enum ["success"]

transfer_idstringrequired

call_control_idstringrequired

nullable false

transferobjectrequired

View nested fields

statestringrequired

messagestringrequired

target_typestringrequired

target_valuestringrequired

started_atstringrequired

format "date-time"nullable true

completed_atstringrequired

format "date-time"nullable true

failed_atstringrequired

format "date-time"nullable true

canceled_atstringrequired

format "date-time"nullable true

terminalbooleanrequired

can_cancelbooleanrequired

resume_originalbooleanrequired

Additional properties: not allowed.

Full schema

Schema

{
  "type": "object",
  "additionalProperties": false,
  "properties": {
    "status": {
      "type": "string",
      "enum": [
        "success"
      ]
    },
    "transfer_id": {
      "type": "string"
    },
    "call_control_id": {
      "type": "string",
      "nullable": false
    },
    "transfer": {
      "type": "object",
      "additionalProperties": false,
      "properties": {
        "state": {
          "type": "string"
        },
        "message": {
          "type": "string"
        },
        "target_type": {
          "type": "string"
        },
        "target_value": {
          "type": "string"
        },
        "started_at": {
          "type": "string",
          "format": "date-time",
          "nullable": true
        },
        "completed_at": {
          "type": "string",
          "format": "date-time",
          "nullable": true
        },
        "failed_at": {
          "type": "string",
          "format": "date-time",
          "nullable": true
        },
        "canceled_at": {
          "type": "string",
          "format": "date-time",
          "nullable": true
        },
        "terminal": {
          "type": "boolean"
        },
        "can_cancel": {
          "type": "boolean"
        },
        "resume_original": {
          "type": "boolean"
        }
      },
      "required": [
        "state",
        "message",
        "target_type",
        "target_value",
        "started_at",
        "completed_at",
        "failed_at",
        "canceled_at",
        "terminal",
        "can_cancel",
        "resume_original"
      ]
    }
  },
  "required": [
    "status",
    "transfer_id",
    "call_control_id",
    "transfer"
  ]
}

400 The request failed validation.

application/json

statusstringrequired

enum ["error"]

messagestringrequired

error_codestringoptional

Public incident or validation code when the endpoint provides one.

nullable true

fieldsobjectoptional

Public validation details when supplied by the endpoint.

Additional properties: not allowed.

Full schema

Schema

{
  "type": "object",
  "additionalProperties": false,
  "required": [
    "status",
    "message"
  ],
  "properties": {
    "status": {
      "type": "string",
      "enum": [
        "error"
      ]
    },
    "message": {
      "type": "string"
    },
    "error_code": {
      "type": "string",
      "nullable": true,
      "description": "Public incident or validation code when the endpoint provides one."
    },
    "fields": {
      "type": "object",
      "additionalProperties": true,
      "description": "Public validation details when supplied by the endpoint."
    }
  }
}

401 The API key or browser token is missing or invalid.

application/json

statusstringrequired

enum ["error"]

messagestringrequired

error_codestringoptional

Public incident or validation code when the endpoint provides one.

nullable true

fieldsobjectoptional

Public validation details when supplied by the endpoint.

Additional properties: not allowed.

Full schema

Schema

{
  "type": "object",
  "additionalProperties": false,
  "required": [
    "status",
    "message"
  ],
  "properties": {
    "status": {
      "type": "string",
      "enum": [
        "error"
      ]
    },
    "message": {
      "type": "string"
    },
    "error_code": {
      "type": "string",
      "nullable": true,
      "description": "Public incident or validation code when the endpoint provides one."
    },
    "fields": {
      "type": "object",
      "additionalProperties": true,
      "description": "Public validation details when supplied by the endpoint."
    }
  }
}

403 The account is not allowed to perform this operation.

application/json

statusstringrequired

enum ["error"]

messagestringrequired

error_codestringoptional

Public incident or validation code when the endpoint provides one.

nullable true

fieldsobjectoptional

Public validation details when supplied by the endpoint.

Additional properties: not allowed.

Full schema

Schema

{
  "type": "object",
  "additionalProperties": false,
  "required": [
    "status",
    "message"
  ],
  "properties": {
    "status": {
      "type": "string",
      "enum": [
        "error"
      ]
    },
    "message": {
      "type": "string"
    },
    "error_code": {
      "type": "string",
      "nullable": true,
      "description": "Public incident or validation code when the endpoint provides one."
    },
    "fields": {
      "type": "object",
      "additionalProperties": true,
      "description": "Public validation details when supplied by the endpoint."
    }
  }
}

404 The requested owned resource was not found.

application/json

statusstringrequired

enum ["error"]

messagestringrequired

error_codestringoptional

Public incident or validation code when the endpoint provides one.

nullable true

fieldsobjectoptional

Public validation details when supplied by the endpoint.

Additional properties: not allowed.

Full schema

Schema

{
  "type": "object",
  "additionalProperties": false,
  "required": [
    "status",
    "message"
  ],
  "properties": {
    "status": {
      "type": "string",
      "enum": [
        "error"
      ]
    },
    "message": {
      "type": "string"
    },
    "error_code": {
      "type": "string",
      "nullable": true,
      "description": "Public incident or validation code when the endpoint provides one."
    },
    "fields": {
      "type": "object",
      "additionalProperties": true,
      "description": "Public validation details when supplied by the endpoint."
    }
  }
}

409 The request conflicts with the current resource or operation state.

application/json

statusstringrequired

enum ["error"]

messagestringrequired

error_codestringoptional

Public incident or validation code when the endpoint provides one.

nullable true

fieldsobjectoptional

Public validation details when supplied by the endpoint.

Additional properties: not allowed.

Full schema

Schema

{
  "type": "object",
  "additionalProperties": false,
  "required": [
    "status",
    "message"
  ],
  "properties": {
    "status": {
      "type": "string",
      "enum": [
        "error"
      ]
    },
    "message": {
      "type": "string"
    },
    "error_code": {
      "type": "string",
      "nullable": true,
      "description": "Public incident or validation code when the endpoint provides one."
    },
    "fields": {
      "type": "object",
      "additionalProperties": true,
      "description": "Public validation details when supplied by the endpoint."
    }
  }
}

429 The request rate limit was exceeded.

application/json

statusstringrequired

enum ["error"]

messagestringrequired

error_codestringoptional

Public incident or validation code when the endpoint provides one.

nullable true

fieldsobjectoptional

Public validation details when supplied by the endpoint.

Additional properties: not allowed.

Full schema

Schema

{
  "type": "object",
  "additionalProperties": false,
  "required": [
    "status",
    "message"
  ],
  "properties": {
    "status": {
      "type": "string",
      "enum": [
        "error"
      ]
    },
    "message": {
      "type": "string"
    },
    "error_code": {
      "type": "string",
      "nullable": true,
      "description": "Public incident or validation code when the endpoint provides one."
    },
    "fields": {
      "type": "object",
      "additionalProperties": true,
      "description": "Public validation details when supplied by the endpoint."
    }
  }
}

500 An unexpected service error occurred.

application/json

statusstringrequired

enum ["error"]

messagestringrequired

error_codestringoptional

Public incident or validation code when the endpoint provides one.

nullable true

fieldsobjectoptional

Public validation details when supplied by the endpoint.

Additional properties: not allowed.

Full schema

Schema

{
  "type": "object",
  "additionalProperties": false,
  "required": [
    "status",
    "message"
  ],
  "properties": {
    "status": {
      "type": "string",
      "enum": [
        "error"
      ]
    },
    "message": {
      "type": "string"
    },
    "error_code": {
      "type": "string",
      "nullable": true,
      "description": "Public incident or validation code when the endpoint provides one."
    },
    "fields": {
      "type": "object",
      "additionalProperties": true,
      "description": "Public validation details when supplied by the endpoint."
    }
  }
}

503 The service is temporarily unavailable.

application/json

statusstringrequired

enum ["error"]

messagestringrequired

error_codestringoptional

Public incident or validation code when the endpoint provides one.

nullable true

fieldsobjectoptional

Public validation details when supplied by the endpoint.

Additional properties: not allowed.

Full schema

Schema

{
  "type": "object",
  "additionalProperties": false,
  "required": [
    "status",
    "message"
  ],
  "properties": {
    "status": {
      "type": "string",
      "enum": [
        "error"
      ]
    },
    "message": {
      "type": "string"
    },
    "error_code": {
      "type": "string",
      "nullable": true,
      "description": "Public incident or validation code when the endpoint provides one."
    },
    "fields": {
      "type": "object",
      "additionalProperties": true,
      "description": "Public validation details when supplied by the endpoint."
    }
  }
}

Sandbox scenarios

Use https://sandbox-api.illyvoip.com with Sandbox credentials and the X-Illyvoip-Sandbox-Scenario header. Omit the header for the documented success default. This header belongs to sandbox requests.

success, not-found, rate-limited, forbidden, service-unavailable

Try this operation in Sandbox · Environment setup and limitations

Cancel transfer

Before you start

Result

Charges and safe retries

Authentication

Request examples

cURL

Node.js

PHP

Python

Request body

application/json

Request behavior

Response fields

HTTP responses

application/json

application/json

application/json

application/json

application/json

application/json

application/json

application/json

application/json

Sandbox scenarios

Related reference