v32

latestOpenAPI 3.1.0MITraw.githubusercontent.com2026-07-312881,4162.7 MB

Realtime

Accept call

Accept an incoming SIP call and configure the realtime session that will handle it.

post/realtime/calls/{call_id}/accept

Path parameters

call_idstring required

The identifier for the call provided in the realtime.call.incoming webhook.

Request body

type'realtime' required

The type of session to create. Always realtime for the Realtime API.

output_modalitiesstring[]

The set of modalities the model can respond with. It defaults to ["audio"], indicating that the model will respond with audio plus a transcript. ["text"] can be used to make the model respond with text only. It is not possible to request both text and audio at the same time.

instructionsstring

The default system instructions (i.e. system message) prepended to model calls. This field allows the client to guide the model on desired responses. The model can be instructed on response content and format, (e.g. "be extremely succinct", "act friendly", "here are examples of good responses") and on audio behavior (e.g. "talk quickly", "inject emotion into your voice", "laugh frequently"). The instructions are not guaranteed to be followed by the model, but they provide guidance to the model on the desired behavior.

Note that the server sets default instructions which will be used if this field is not set and are visible in the session.created event at the start of the session.

includestring[]

Additional fields to include in server outputs.

item.input_audio_transcription.logprobs: Include logprobs for input audio transcription.

parallel_tool_callsboolean

Whether the model may call multiple tools in parallel. Only supported by reasoning Realtime models such as gpt-realtime-2.

Example request

{
  "audio": {
    "output": {
      "voice": {
        "id": "voice_1234"
      }
    }
  }
}

Response

Call accepted successfully.