IllyVoIPdevelopers

Voice API

Answer inbound Voice API call

Answers a ringing inbound call that is routed to Voice API Control.

Try in API Playground ↗Sign in to prepare and run this request.
POST/api/v1/voice/call-control/answer

Before you start

Use the public call_id from a ringing event or active-call result while can_answer_via_api is true.

Result

Save call_control_id for the following actions.

Charges and safe retries

Retry an uncertain Answer with the same call_id; an ended call cannot be answered.

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

Node.js

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

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

PHP

PHP
<?php
$ch = curl_init('https://api.illyvoip.com/api/v1/voice/call-control/answer');
curl_setopt_array($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 => '{
    "call_id": "YOUR_CALL_ID"
}',
]);

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

echo $status . PHP_EOL;
echo $response;

Python

Python
import os
import json
import requests

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

call_idstringrequired

Public CALL- reference from an incoming call_ringing webhook or the active-calls endpoint.

timeout_secondsintegeroptional

Maximum incoming call duration in seconds: 15–14400; default 14400. Retried Answer requests keep the original duration limit.

Additional properties: not allowed.

Full schema
Schema
{
  "type": "object",
  "additionalProperties": false,
  "properties": {
    "call_id": {
      "type": "string",
      "description": "Public CALL- reference from an incoming call_ringing webhook or the active-calls endpoint."
    },
    "timeout_seconds": {
      "type": "integer",
      "description": "Maximum incoming call duration in seconds: 15–14400; default 14400. Retried Answer requests keep the original duration limit."
    }
  },
  "required": [
    "call_id"
  ]
}
Example body
JSON
{
  "call_id": "CALL-0123456789ABCDEF01234567"
}

Request behavior

Use the public call_id from a call_ringing webhook with can_answer_via_api: true, or from the active-calls endpoint. Answer while the call is still ringing. The response returns a call_control_id for subsequent Voice API actions. If a request times out, retry Answer with the same call_id; it reuses the existing session. A call that has ended cannot be answered.

Response fields

  • status: Request outcome. Read the resource state separately; success does not always mean delivery or completion.
  • call_id: Public call reference shared by call history and lifecycle events.
  • call_control_id: Control session reference returned by Create or Answer; use it for subsequent live actions.
  • state: Current state of this call or operation.

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",
  "call_id": "CALL-0123456789ABCDEF01234567",
  "call_control_id": "vapi_760da5ee5a3c8b70777bae20fbda",
  "state": "active"
}
statusstringrequired
enum ["success"]
call_idstringrequired
call_control_idstringrequired
nullable false
statestringrequired

Additional properties: not allowed.

Full schema
Schema
{
  "type": "object",
  "additionalProperties": false,
  "properties": {
    "status": {
      "type": "string",
      "enum": [
        "success"
      ]
    },
    "call_id": {
      "type": "string"
    },
    "call_control_id": {
      "type": "string",
      "nullable": false
    },
    "state": {
      "type": "string"
    }
  },
  "required": [
    "status",
    "call_id",
    "call_control_id",
    "state"
  ]
}
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."
    }
  }
}
402 The account has insufficient available credit.

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

List active callsGet Voice API statusCreate callExecute action chainPlay audioSpeak textGather DTMF or speechGet call statusWaitTransfer callGet transfer statusCancel transferHold callUnhold callSend DTMFEnd call

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