> For complete lifecycle-event payload schemas and examples, use the canonical overview: Session /api/sessions; Room lifecycle, members, and room playback /api/rooms; Session playback /api/playback; Recording /api/recording; DTMF /api/keypad-input; Messages /api/messages; WebSocket Session /api/web-socket. Use /api/event-delivery for transport behavior. Endpoint pages name relevant events, but these overviews are the canonical references.

# Collect DTMF input with optional playback

POST https://api.telekesher.dev/v1/sessions/{uuid}/dtmf/collect
Content-Type: application/json

**Rate limit: Per command** · **Burst:** 4 · **Refill:** 0.8 req/s

Collect a complete DTMF response from the caller and optionally play audio prompts first. The operation groups the caller's keys and applies the configured digit-count, timeout, terminator, and regular-expression validation rules.

The platform validates and prepares every prompt URL before admitting the command. An unavailable prompt returns a synchronous HTTP error and does not trigger a webhook. A `202 Accepted` response means that the command was queued. The application stores its `operation_uuid` and matches it to the same field in the terminal `digits.collected` event.

The platform runs exactly one prompt-and-collect cycle and emits one `digits.collected` event with the collected value and outcome `status`. It does not retry the cycle. The application inspects `status` and submits another command when needed, such as a command with an invalid-PIN prompt after `status: invalid`.

The platform also emits a `dtmf.received` event immediately for every key press, whether or not a collection is active. Each event contains one key and its `duration_ms`; it does not group digits or apply collection rules. These events continue during a collection.

**Triggered webhook:** `digits.collected`.

This POST and its cancel DELETE each use a separate rate-limit bucket with the same configuration.

See [Keypad input lifecycle events](/api/keypad-input#lifecycle-events) for complete payload schemas and examples.

Reference: https://docs.vorbal.dev/api/keypad-input/collect

## Authentication

- `Authorization` header (bearer token, required) — Application auth. Send `Authorization: Bearer <app_uuid>:<api_key>` using any active key in the app's collection. See [Authentication](https://voice-platform.docs.buildwithfern.com/api/authentication) for details.

## Request

### Path parameters

- `uuid` (string, required) — [Session](/api/sessions) identifier.

### Headers

- `Idempotency-Key` (string, optional) — Optional key for safely retrying mutating requests. See [Idempotency](https://voice-platform.docs.buildwithfern.com/idempotency) for details.
- `Operation-Id` (string, optional) — optional client-supplied lowercase RFC-4122 v4 UUID returned as operation_uuid; platform generates one when omitted; correlation metadata distinct from Idempotency-Key.

### Body (application/json)

- `between_digits_timeout_ms` (integer, required) — Milliseconds to wait between digits before timing out.
- `first_digit_timeout_ms` (integer, required) — Milliseconds to wait for the first digit before timing out.
- `max_digits` (integer, required) — Maximum digits to collect. Must be >= min_digits.
- `min_digits` (integer, required)
- `terminators` (list of enum, required) — DTMF terminator characters. Only # and * allowed.
  - Allowed values: `#`, `*`
- `prompt_files` (list of string, optional) — Optional HTTP/HTTPS WAV or MP3 URLs to play as the prompt before collecting digits.
- `validation` (object, optional) — Optional input validation.
  - `regex` (string, optional) — RE2 regular expression the collected digits must match (no whitespace, \<=256 chars). On match-and-fail, status is `invalid`.

## Response

### 202

Command accepted for async execution

- `operation_uuid` (string, required)
- `status` (enum, required)
  - Allowed values: `in_progress`, `completed`
- `already_ended` (true, optional) — Optional. Set to `true` on idempotent terminal commands when the session was already in a terminal state at the time the request was received. Absent otherwise.

## Examples

**Request**

```json
{
  "between_digits_timeout_ms": 2000,
  "first_digit_timeout_ms": 10000,
  "max_digits": 6,
  "min_digits": 4,
  "terminators": [
    "#"
  ],
  "prompt_files": [
    "https://cdn.example.com/enter-pin.wav"
  ],
  "validation": {
    "regex": "^[0-9]{4,6}$"
  }
}
```

**Response**

```json
{
  "operation_uuid": "550e8400-e29b-41d4-a716-446655440000",
  "status": "in_progress"
}
```

**SDK Code**

```python Keypad Input_playPromptAndCollectDTMFDigits_example
import requests

url = "https://api.telekesher.dev/v1/sessions/uuid/dtmf/collect"

payload = {
    "between_digits_timeout_ms": 2000,
    "first_digit_timeout_ms": 10000,
    "max_digits": 6,
    "min_digits": 4,
    "terminators": ["#"],
    "prompt_files": ["https://cdn.example.com/enter-pin.wav"],
    "validation": { "regex": "^[0-9]{4,6}$" }
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.json())
```

```javascript Keypad Input_playPromptAndCollectDTMFDigits_example
const url = 'https://api.telekesher.dev/v1/sessions/uuid/dtmf/collect';
const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: '{"between_digits_timeout_ms":2000,"first_digit_timeout_ms":10000,"max_digits":6,"min_digits":4,"terminators":["#"],"prompt_files":["https://cdn.example.com/enter-pin.wav"],"validation":{"regex":"^[0-9]{4,6}$"}}'
};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}
```

```go Keypad Input_playPromptAndCollectDTMFDigits_example
package main

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

func main() {

	url := "https://api.telekesher.dev/v1/sessions/uuid/dtmf/collect"

	payload := strings.NewReader("{\n  \"between_digits_timeout_ms\": 2000,\n  \"first_digit_timeout_ms\": 10000,\n  \"max_digits\": 6,\n  \"min_digits\": 4,\n  \"terminators\": [\n    \"#\"\n  ],\n  \"prompt_files\": [\n    \"https://cdn.example.com/enter-pin.wav\"\n  ],\n  \"validation\": {\n    \"regex\": \"^[0-9]{4,6}$\"\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(res)
	fmt.Println(string(body))

}
```

```ruby Keypad Input_playPromptAndCollectDTMFDigits_example
require 'uri'
require 'net/http'

url = URI("https://api.telekesher.dev/v1/sessions/uuid/dtmf/collect")

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  \"between_digits_timeout_ms\": 2000,\n  \"first_digit_timeout_ms\": 10000,\n  \"max_digits\": 6,\n  \"min_digits\": 4,\n  \"terminators\": [\n    \"#\"\n  ],\n  \"prompt_files\": [\n    \"https://cdn.example.com/enter-pin.wav\"\n  ],\n  \"validation\": {\n    \"regex\": \"^[0-9]{4,6}$\"\n  }\n}"

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

```java Keypad Input_playPromptAndCollectDTMFDigits_example
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.post("https://api.telekesher.dev/v1/sessions/uuid/dtmf/collect")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"between_digits_timeout_ms\": 2000,\n  \"first_digit_timeout_ms\": 10000,\n  \"max_digits\": 6,\n  \"min_digits\": 4,\n  \"terminators\": [\n    \"#\"\n  ],\n  \"prompt_files\": [\n    \"https://cdn.example.com/enter-pin.wav\"\n  ],\n  \"validation\": {\n    \"regex\": \"^[0-9]{4,6}$\"\n  }\n}")
  .asString();
```

```php Keypad Input_playPromptAndCollectDTMFDigits_example
<?php
require_once('vendor/autoload.php');

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://api.telekesher.dev/v1/sessions/uuid/dtmf/collect', [
  'body' => '{
  "between_digits_timeout_ms": 2000,
  "first_digit_timeout_ms": 10000,
  "max_digits": 6,
  "min_digits": 4,
  "terminators": [
    "#"
  ],
  "prompt_files": [
    "https://cdn.example.com/enter-pin.wav"
  ],
  "validation": {
    "regex": "^[0-9]{4,6}$"
  }
}',
  'headers' => [
    'Authorization' => 'Bearer <token>',
    'Content-Type' => 'application/json',
  ],
]);

echo $response->getBody();
```

```csharp Keypad Input_playPromptAndCollectDTMFDigits_example
using RestSharp;

var client = new RestClient("https://api.telekesher.dev/v1/sessions/uuid/dtmf/collect");
var request = new RestRequest(Method.POST);
request.AddHeader("Authorization", "Bearer <token>");
request.AddHeader("Content-Type", "application/json");
request.AddParameter("application/json", "{\n  \"between_digits_timeout_ms\": 2000,\n  \"first_digit_timeout_ms\": 10000,\n  \"max_digits\": 6,\n  \"min_digits\": 4,\n  \"terminators\": [\n    \"#\"\n  ],\n  \"prompt_files\": [\n    \"https://cdn.example.com/enter-pin.wav\"\n  ],\n  \"validation\": {\n    \"regex\": \"^[0-9]{4,6}$\"\n  }\n}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
```

```swift Keypad Input_playPromptAndCollectDTMFDigits_example
import Foundation

let headers = [
  "Authorization": "Bearer <token>",
  "Content-Type": "application/json"
]
let parameters = [
  "between_digits_timeout_ms": 2000,
  "first_digit_timeout_ms": 10000,
  "max_digits": 6,
  "min_digits": 4,
  "terminators": ["#"],
  "prompt_files": ["https://cdn.example.com/enter-pin.wav"],
  "validation": ["regex": "^[0-9]{4,6}$"]
] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://api.telekesher.dev/v1/sessions/uuid/dtmf/collect")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error as Any)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()
```