curl -X POST 'https://api.openai.com/v1/realtime/calls' \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -F 'sdp=example-sdp'

# POST /realtime/calls (OpenAI API)
Base URL: https://api.openai.com/v1
Auth: Authorization; OpenAI API key; required.
Request formats: multipart/form-data, application/sdp.
Last verified: 2026-10-20

> Create call

## 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/calls' \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -F 'sdp=example-sdp'

## Parameters
| Name | In | Type | Required | Description |
| :--- | :--- | :--- | :--- | :--- |
| sdp | body | string | Yes | WebRTC Session Description Protocol (SDP) offer generated by the caller. |
| session | body | object | No | Optional session configuration to apply before the realtime session is create... |

## Response example
"string"

---
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POST

POST /realtime/calls — OpenAI API

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

OpenAI API

Create call

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
→ 201 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/calls' \  -H "Authorization: Bearer $OPENAI_API_KEY" \  -F 'sdp=example-sdp'

Parameters

Name	In	Type	Required	Description
sdp	body	string	Yes	WebRTC Session Description Protocol (SDP) offer generated by the caller.
session	body	object	No	Optional session configuration to apply before the realtime session is created. Use the same parameters you would send in a [`create client secret`](https://developers.openai.com/api/reference/resources/realtime/subresources/client_secrets/methods/create) request.

Response 200 OK

"string"

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