Realtime

Create transcription session

Create an ephemeral API token for use in client-side applications with the Realtime API specifically for realtime transcriptions. Can be configured with the same session parameters as the transcription_session.update client event.

It responds with a session object, plus a client_secret key which contains a usable ephemeral API token that can be used to authenticate browser clients for the Realtime API.

Returns the created Realtime transcription session object, plus an ephemeral key.

post/realtime/transcription_sessions

Request body

input_audio_format'pcm16' | 'g711_ulaw' | 'g711_alaw'

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.

includestring[]

The set of items to include in the transcription. Current available items are: item.input_audio_transcription.logprobs

Response

Session created successfully.

modalitiesstring[]

The set of modalities the model can respond with. To disable audio, set this to ["text"].

input_audio_formatstring

The format of input audio. Options are pcm16, g711_ulaw, or g711_alaw.

Changes

Changed in 3 of the 163 revisions of this API.7614

Aug 5, 2026ab0c5306e39025See the full diff
- ●
  added the new gpt-live-transcribe enum value to the // response property for the response status
  response-property-enum-value-added
- ●
  added the new gpt-transcribe enum value to the // response property for the response status
  response-property-enum-value-added
- ○
  added the new optional request property /
  new-optional-request-property
- ○
  added the new optional request property /
  new-optional-request-property
- ○
  added the new gpt-live-transcribe enum value to the request property //
  request-property-enum-value-added
- ○
  added the new gpt-transcribe enum value to the request property //
  request-property-enum-value-added
- ○
  added the optional property / to the response with the status
  response-optional-property-added
This revision also has 2 changes that name no endpoint, such as unreferenced schemas being removed. See the revision's changelog
May 13, 202674cbcf73838f748See the full diff
- ▲
  request property / was restricted to a list of enum values
  request-property-became-enum
- ▲
  removed the enum value gpt-4o-mini-transcribe of the request property /
  request-property-enum-value-removed
- ▲
  removed the enum value gpt-4o-transcribe of the request property /
  request-property-enum-value-removed
- ▲
  removed the enum value semantic_vad of the request property /
  request-property-enum-value-removed
- ▲
  removed the enum value whisper-1 of the request property /
  request-property-enum-value-removed
- ▲
  the / request property type changed from string to no type
  request-property-type-changed
- ▲
  the / response's property type changed from string to no type for status
  response-property-type-changed
- ●
  removed the request property
  request-property-removed
- ●
  removed the request property /
  request-property-removed
- ●
  removed the request property /
  request-property-removed
- ●
  removed the request property /
  request-property-removed
- ○
  added the new optional request property /
  new-optional-request-property
- ○
  added subschema #1 subschema #2 to the / request property anyOf list
  request-property-any-of-added
- ○
  the request property default value server_vad was removed
  request-property-default-value-removed
- ○
  added the new item.input_audio_transcription.logprobs enum value to the request property /
  request-property-enum-value-added
- ○
  added subschema #1 subschema #2 to the / response property anyOf list for the response status
  response-property-any-of-added
- ○
  removed the gpt-4o-mini-transcribe enum value from the / response property for the response status
  response-property-enum-value-removed
- ○
  removed the gpt-4o-transcribe enum value from the / response property for the response status
  response-property-enum-value-removed
- ○
  removed the whisper-1 enum value from the / response property for the response status
  response-property-enum-value-removed
This revision also has 40 changes that name no endpoint, such as unreferenced schemas being removed. See the revision's changelog
Mar 22, 202541844462b8731See the full diff
- ○
  endpoint added
  endpoint-added

Full history