curl -X POST 'https://api.openai.com/v1/realtime/transcription_sessions' \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H 'Content-Type: application/json' \
  -d '{}'

# POST /realtime/transcription_sessions (OpenAI API)
Base URL: https://api.openai.com/v1
Auth: Authorization; OpenAI API key; required.
Request formats: application/json.
Last verified: 2026-10-20

> Create transcription session

## Critical Gotchas
* The Responses API is the primary interface for new text and tool workflows; Chat Completions remains a separate compatibility API.
* Audio transcription uploads use multipart form data rather than a JSON request body.

## cURL
curl -X POST 'https://api.openai.com/v1/realtime/transcription_sessions' \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H 'Content-Type: application/json' \
  -d '{}'

## Parameters
| Name | In | Type | Required | Description |
| :--- | :--- | :--- | :--- | :--- |
| turn_detection | body | object | No | Configuration for turn detection. Can be set to `null` to turn off. Server VA... |
| input_audio_noise_reduction | body | object | No | Configuration for input audio noise reduction. This can be set to `null` to t... |
| input_audio_format | body | string | No | The format of input audio. Options are `pcm16`, `g711_ulaw`, or `g711_alaw`.... |
| input_audio_transcription | body | object | No | Request body field input_audio_transcription. |
| include | body | string[] | No | The set of items to include in the transcription. Current available items are... |

## Response example
{"client_secret":{"value":"string","expires_at":0},"modalities":{}}

---
Need an API key? Get one at https://platform.openai.com/api-keys

POST

POST /realtime/transcription_sessions — OpenAI API

OpenAI API key (required); https://api.openai.com/v1

OpenAI API

Create transcription session

Base URL: https://api.openai.com/v1
Auth: Authorization: Bearer <OPENAI_API_KEY>
Last verified: 2026-10-20 · upstream hash matched

Actions Try in browser→

Agents: curl -H "Accept: text/markdown" this URL
→ 290 tokens · Vary: Accept

Critical gotchas

The Responses API is the primary interface for new text and tool workflows; Chat Completions remains a separate compatibility API.

Audio transcription uploads use multipart form data rather than a JSON request body.

cURL

curl -X POST 'https://api.openai.com/v1/realtime/transcription_sessions' \  -H "Authorization: Bearer $OPENAI_API_KEY" \  -H 'Content-Type: application/json' \  -d '{}'

Parameters

Name	In	Type	Required	Description
turn_detection	body	object	No	Configuration for turn detection. Can be set to `null` to turn off. Server VAD means that the model will detect the start and end of speech based on audio volume and respond at the end of user speech.
input_audio_noise_reduction	body	object	No	Configuration for input audio noise reduction. This can be set to `null` to turn off. Noise reduction filters audio added to the input audio buffer before it is sent to VAD and the model. Filtering the audio can improve VAD and turn detection accuracy (reducing false positives) and model performance by improving perception of the input audio.
input_audio_format	body	string	No	The format of input audio. Options are `pcm16`, `g711_ulaw`, or `g711_alaw`. For `pcm16`, input audio must be 16-bit PCM at a 24kHz sample rate, single channel (mono), and little-endian byte order.
input_audio_transcription	body	object	No	Request body field input_audio_transcription.
include	body	string[]	No	The set of items to include in the transcription. Current available items are: `item.input_audio_transcription.logprobs`

Response 200 OK

{
  "client_secret": {
    "value": "string",
    "expires_at": 0
  },
  "modalities": {},
  "input_audio_format": "string",
  "input_audio_transcription": {
    "model": "string",
    "language": "string",
    "languages": [
      "string"
    ],
    "prompt": "string"
  },
  "turn_detection": {
    "type": "string",
    "threshold": 0,
    "prefix_padding_ms": 0,
    "silence_duration_ms": 0
  }
}

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