> For complete lifecycle-event payload schemas and examples, use the canonical overview: Session /api/sessions; Room lifecycle, participants, 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.

# List room participants

GET https://api.vorbal.dev/api/v1/rooms/{room_id}/participants

List active [room participants](/api/room-participants), sorted by session
`uuid` in ascending order.

This endpoint returns one non-paginated result. Omitting `limit` returns every
participant when the full result set is within the system result ceiling. Setting
`limit` returns at most that many participants and sets `has_more` to `true` when
additional participants matched.

The system checks the full result set against its ceiling before applying
`limit`. If the full set exceeds the ceiling, the request returns `413` and a
smaller `limit` cannot make it succeed.

Reference: https://docs.vorbal.dev/api/room-participants/list

## Authentication

- `Authorization` header (bearer token, required) — Send `Authorization: Bearer <app_uuid>:<api_key>` using an active API key. See [Authentication](https://voice-platform.docs.buildwithfern.com/api/authentication) for details.

## Request

### Path parameters

- `room_id` (string, required) — Case-sensitive [room](/api/rooms) identifier.

### Query parameters

- `limit` (integer, optional) — Sets the maximum number of participants in the response. Omitting it returns every participant when the full result set is within the system ceiling. A non-positive value returns `400`.

## Response

### 200

Participants of the room

- `has_more` (boolean, required) — `true` when more participants matched than `limit` allowed; raise `limit` to retrieve all of them.
- `participants` (list of object, required)
  - `muted` (boolean, required) — Whether the participant is currently muted in the room.
  - `uuid` (string, required) — Session UUID of the participant.
- `room_id` (string, required)

## Errors

### 400 Bad Request Error

Missing `Authorization`, malformed Bearer credentials, or an invalid `limit`. A syntactically valid credential with an invalid API key returns `401` instead.

- `code` (enum, required) — Stable, machine-readable error class from a closed set. Branch on this for programmatic handling. New codes are only added with a documented API change. Maps to the HTTP status as follows: `invalid_request` (400/405/406/415/422), `invalid_authorization_header` (400), `payload_too_large` and `result_set_too_large` (413), `unauthorized` (401), `forbidden` (403), `not_found` (404), `recording_not_active` (400); `conflict` and `room_full` (409), `rate_limited` (429), and `unavailable` (503/529). Unexpected failures use the separate `InternalErrorResponse` schema. Note: `413` is the only status shared by two codes — `payload_too_large` means the request body exceeded its size cap, while `result_set_too_large` means a list response exceeded the system result ceiling (narrow the query with filters and retry). Note: `unavailable` maps to multiple HTTP statuses, which represent different retry conditions: `503` means a required store or service is temporarily unavailable, and `529` means the platform is overloaded. Use the HTTP status and operation description, not just `code`, to distinguish them.
  - Allowed values: `invalid_request`, `invalid_authorization_header`, `payload_too_large`, `result_set_too_large`, `unauthorized`, `forbidden`, `not_found`, `conflict`, `recording_not_active`, `room_full`, `rate_limited`, `unavailable`
- `message` (string, required) — Human-readable, English-only error message. For display only — phrasing may change without notice, so branch on `code`, not on this string.

### 401 Unauthorized Error

The Bearer credential is syntactically valid but its API key is invalid. Missing `Authorization` or malformed Bearer credentials return `400 invalid_authorization_header`.

- `code` (enum, required) — Stable, machine-readable error class from a closed set. Branch on this for programmatic handling. New codes are only added with a documented API change. Maps to the HTTP status as follows: `invalid_request` (400/405/406/415/422), `invalid_authorization_header` (400), `payload_too_large` and `result_set_too_large` (413), `unauthorized` (401), `forbidden` (403), `not_found` (404), `recording_not_active` (400); `conflict` and `room_full` (409), `rate_limited` (429), and `unavailable` (503/529). Unexpected failures use the separate `InternalErrorResponse` schema. Note: `413` is the only status shared by two codes — `payload_too_large` means the request body exceeded its size cap, while `result_set_too_large` means a list response exceeded the system result ceiling (narrow the query with filters and retry). Note: `unavailable` maps to multiple HTTP statuses, which represent different retry conditions: `503` means a required store or service is temporarily unavailable, and `529` means the platform is overloaded. Use the HTTP status and operation description, not just `code`, to distinguish them.
  - Allowed values: `invalid_request`, `invalid_authorization_header`, `payload_too_large`, `result_set_too_large`, `unauthorized`, `forbidden`, `not_found`, `conflict`, `recording_not_active`, `room_full`, `rate_limited`, `unavailable`
- `message` (string, required) — Human-readable, English-only error message. For display only — phrasing may change without notice, so branch on `code`, not on this string.

### 404 Not Found Error

The room was not found.

- `code` (enum, required) — Stable, machine-readable error class from a closed set. Branch on this for programmatic handling. New codes are only added with a documented API change. Maps to the HTTP status as follows: `invalid_request` (400/405/406/415/422), `invalid_authorization_header` (400), `payload_too_large` and `result_set_too_large` (413), `unauthorized` (401), `forbidden` (403), `not_found` (404), `recording_not_active` (400); `conflict` and `room_full` (409), `rate_limited` (429), and `unavailable` (503/529). Unexpected failures use the separate `InternalErrorResponse` schema. Note: `413` is the only status shared by two codes — `payload_too_large` means the request body exceeded its size cap, while `result_set_too_large` means a list response exceeded the system result ceiling (narrow the query with filters and retry). Note: `unavailable` maps to multiple HTTP statuses, which represent different retry conditions: `503` means a required store or service is temporarily unavailable, and `529` means the platform is overloaded. Use the HTTP status and operation description, not just `code`, to distinguish them.
  - Allowed values: `invalid_request`, `invalid_authorization_header`, `payload_too_large`, `result_set_too_large`, `unauthorized`, `forbidden`, `not_found`, `conflict`, `recording_not_active`, `room_full`, `rate_limited`, `unavailable`
- `message` (string, required) — Human-readable, English-only error message. For display only — phrasing may change without notice, so branch on `code`, not on this string.

### 406 Not Acceptable Error

The public API returns JSON and does not expose a Server-Sent Events representation. Requests that explicitly negotiate `text/event-stream` without accepting JSON are rejected.

- `code` (enum, required) — Stable, machine-readable error class from a closed set. Branch on this for programmatic handling. New codes are only added with a documented API change. Maps to the HTTP status as follows: `invalid_request` (400/405/406/415/422), `invalid_authorization_header` (400), `payload_too_large` and `result_set_too_large` (413), `unauthorized` (401), `forbidden` (403), `not_found` (404), `recording_not_active` (400); `conflict` and `room_full` (409), `rate_limited` (429), and `unavailable` (503/529). Unexpected failures use the separate `InternalErrorResponse` schema. Note: `413` is the only status shared by two codes — `payload_too_large` means the request body exceeded its size cap, while `result_set_too_large` means a list response exceeded the system result ceiling (narrow the query with filters and retry). Note: `unavailable` maps to multiple HTTP statuses, which represent different retry conditions: `503` means a required store or service is temporarily unavailable, and `529` means the platform is overloaded. Use the HTTP status and operation description, not just `code`, to distinguish them.
  - Allowed values: `invalid_request`, `invalid_authorization_header`, `payload_too_large`, `result_set_too_large`, `unauthorized`, `forbidden`, `not_found`, `conflict`, `recording_not_active`, `room_full`, `rate_limited`, `unavailable`
- `message` (string, required) — Human-readable, English-only error message. For display only — phrasing may change without notice, so branch on `code`, not on this string.

### 413 Content Too Large Error

The full participant set exceeds the system result ceiling. The system checks this ceiling before applying `limit`, and the endpoint has no narrowing filter. The standard error envelope contains `code: result_set_too_large`.

- `code` (enum, required) — Stable, machine-readable error class from a closed set. Branch on this for programmatic handling. New codes are only added with a documented API change. Maps to the HTTP status as follows: `invalid_request` (400/405/406/415/422), `invalid_authorization_header` (400), `payload_too_large` and `result_set_too_large` (413), `unauthorized` (401), `forbidden` (403), `not_found` (404), `recording_not_active` (400); `conflict` and `room_full` (409), `rate_limited` (429), and `unavailable` (503/529). Unexpected failures use the separate `InternalErrorResponse` schema. Note: `413` is the only status shared by two codes — `payload_too_large` means the request body exceeded its size cap, while `result_set_too_large` means a list response exceeded the system result ceiling (narrow the query with filters and retry). Note: `unavailable` maps to multiple HTTP statuses, which represent different retry conditions: `503` means a required store or service is temporarily unavailable, and `529` means the platform is overloaded. Use the HTTP status and operation description, not just `code`, to distinguish them.
  - Allowed values: `invalid_request`, `invalid_authorization_header`, `payload_too_large`, `result_set_too_large`, `unauthorized`, `forbidden`, `not_found`, `conflict`, `recording_not_active`, `room_full`, `rate_limited`, `unavailable`
- `message` (string, required) — Human-readable, English-only error message. For display only — phrasing may change without notice, so branch on `code`, not on this string.

### 500 Internal Server Error

An unexpected platform failure. Quote `support_id` to support; the technical cause and vendor event identifier are never exposed.

- `code` ("internal_error", required)
- `message` ("An internal error occurred", required)
- `support_id` (string, required) — Identifier for this error occurrence, starting with `err_`. Preserve the complete value and quote it when you contact support.

## Examples

**Response**

```json
{
  "has_more": true,
  "participants": [
    {
      "muted": false,
      "uuid": "session-id"
    }
  ],
  "room_id": "string"
}
```

**SDK Code**

```python
import requests

url = "https://api.vorbal.dev/api/v1/rooms/room_id/participants"

headers = {"Authorization": "Bearer <token>"}

response = requests.get(url, headers=headers)

print(response.json())
```

```javascript
const url = 'https://api.vorbal.dev/api/v1/rooms/room_id/participants';
const options = {method: 'GET', headers: {Authorization: 'Bearer <token>'}};

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

```go
package main

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

func main() {

	url := "https://api.vorbal.dev/api/v1/rooms/room_id/participants"

	req, _ := http.NewRequest("GET", url, nil)

	req.Header.Add("Authorization", "Bearer <token>")

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

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

	fmt.Println(res)
	fmt.Println(string(body))

}
```

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

url = URI("https://api.vorbal.dev/api/v1/rooms/room_id/participants")

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

request = Net::HTTP::Get.new(url)
request["Authorization"] = 'Bearer <token>'

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

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

HttpResponse<String> response = Unirest.get("https://api.vorbal.dev/api/v1/rooms/room_id/participants")
  .header("Authorization", "Bearer <token>")
  .asString();
```

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

$client = new \GuzzleHttp\Client();

$response = $client->request('GET', 'https://api.vorbal.dev/api/v1/rooms/room_id/participants', [
  'headers' => [
    'Authorization' => 'Bearer <token>',
  ],
]);

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

```csharp
using RestSharp;

var client = new RestClient("https://api.vorbal.dev/api/v1/rooms/room_id/participants");
var request = new RestRequest(Method.GET);
request.AddHeader("Authorization", "Bearer <token>");
IRestResponse response = client.Execute(request);
```

```swift
import Foundation

let headers = ["Authorization": "Bearer <token>"]

let request = NSMutableURLRequest(url: NSURL(string: "https://api.vorbal.dev/api/v1/rooms/room_id/participants")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "GET"
request.allHTTPHeaderFields = headers

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()
```