---
title: "OpenAI’s Realtime WebRTC API: A Guide to the Beta Implementation"
canonical: "https://cogint.ai/openai-realtime-webrtc-beta-guide-summary/"
description: "A condensed guide to OpenAI’s Beta Realtime WebRTC API: browser microphone capture, peer-connection offer/answer, audio media, the oai-events DataChannel, session configuration, function calling, interruption handling, orderly shutdown, and a browser-based Google AIY Voice Kit experiment."
author: "Chad Hart"
published: "2025-03-18T00:00:00.000-04:00"
modified: "2026-07-14T14:39:40.000-04:00"
site_tags:
  - "voice-ai"
  - "openai"
  - "webrtc"
machine_topics:
  - "Voice AI"
  - "OpenAI"
  - "WebRTC"
is_based_on:
  - "https://webrtchacks.com/the-unofficial-guide-to-openai-realtime-webrtc-api/"
content_fidelity: "faithful_html_conversion"
annotations_not_part_of_article: true
word_count: 668
approx_tokens: 889
content_hash: "739c2d8d0da29b4dac6c9f18323380a9d15218dfaf375478d4fa59a98d8f7bd7"
markdown_url: "https://cogint.ai/openai-realtime-webrtc-beta-guide-summary/index.md"
---

# Machine-oriented context

This section is generated metadata and is not part of the original article.

## Summary

A condensed guide to OpenAI’s Beta Realtime WebRTC API: browser microphone capture, peer-connection offer/answer, audio media, the oai-events DataChannel, session configuration, function calling, interruption handling, orderly shutdown, and a browser-based Google AIY Voice Kit experiment.

## Key findings

- WebRTC carried audio while a DataChannel carried JSON Realtime API control and event messages.
- Session behavior was configured after connection with session.update and related events.
- Function calls and their results used the same DataChannel event path.
- An orderly shutdown was needed to finish output audio before stopping capture and closing the peer connection.
- Running the browser implementation on the AIY Voice Kit’s Raspberry Pi was more practical than rebuilding against archived hardware libraries.

## Provenance and sources

- Adaptation of [The Unofficial Guide to OpenAI’s (Beta) Realtime WebRTC API](https://webrtchacks.com/the-unofficial-guide-to-openai-realtime-webrtc-api/), originally published 2025-03-18; relationship: Condensed implementation guide.
- Tested or observed at: 2025-03-18
- [The Unofficial Guide to OpenAI’s (Beta) Realtime WebRTC API](https://webrtchacks.com/the-unofficial-guide-to-openai-realtime-webrtc-api/) — webrtcHacks; original hands-on guide
- [Realtime API with WebRTC](https://platform.openai.com/docs/guides/realtime-webrtc) — OpenAI; official developer documentation

## Limitations

- The article intentionally describes the Beta API and should not be read as current GA API documentation.
- Endpoint names and event semantics may have changed after the observation date.

# Published article

Faithful Markdown conversion of the human-readable article follows.

This summary is based on my March 2025 webrtcHacks investigation, [The Unofficial Guide to OpenAI’s (Beta) Realtime WebRTC API](https://webrtchacks.com/the-unofficial-guide-to-openai-realtime-webrtc-api/?ref=cogint.ai). I started the project because I wanted to repurpose an old Google AIY Voice Kit for ChatGPT voice mode. Connecting the microphone to OpenAI’s sample was easy. Understanding the full WebRTC and Realtime API flow beyond “say hello to the bot” was not.

The resulting article became a long, step-by-step guide with code, logs, diagrams, and a live example. This is the shorter version of what that investigation found. It describes the Beta implementation available when the original article was published.

## The architecture was mostly standard WebRTC

The browser first used `getUserMedia` to capture a microphone track. That track was added to a new `RTCPeerConnection`, while the incoming track handler connected OpenAI’s generated audio to an HTML audio element. The browser also created a DataChannel named `oai-events` for Realtime API control messages.

This separation is important. WebRTC carried the actual audio, while the DataChannel carried JSON events that configured the model, started responses, reported transcripts, and invoked functions. From an application perspective, the DataChannel behaved a lot like a WebSocket. It simply traveled with the WebRTC session.

The connection used the usual offer/answer process. The browser created an SDP offer and sent it to OpenAI’s Beta Realtime endpoint. OpenAI returned an SDP answer, which the browser applied as the remote description. WebRTC then handled the audio transport, encryption, congestion control, and network details behind the `RTCPeerConnection` APIs.

## Session behavior came from DataChannel events

Establishing the media connection was only the first part. The application still needed to tell the model how to behave.

When the DataChannel opened, the example sent a `session.update` message with the voice, instructions, input transcription settings, turn-detection behavior, and available functions. It could then send `response.create` to ask the model to begin speaking.

Incoming events described the state of the conversation. Some contained user or assistant transcripts. Others indicated that speech had started or stopped, an audio response had finished, a response was canceled, or a function call was ready. The guide walked through many of these events because the ordering and naming were a major part of building anything beyond the smallest demo.

Interruptions were split between WebRTC playback and Realtime API state. When the user spoke over the assistant, server-side voice activity detection could stop the audio response. The client still needed to pay attention to the corresponding events so its interface and conversation state stayed synchronized.

## Function calling also traveled over the DataChannel

I added a simple `end_session` function so the user could verbally ask the application to stop. The function definition was included in the initial session configuration. When the model selected it, the client received a completed function-call event over the DataChannel.

The example then generated a final goodbye, waited for the output audio to finish, stopped the microphone track, and closed the peer connection. This exposed a practical detail that short samples often skip: a voice application needs an orderly shutdown path, especially if it wants the user to hear a final response before media capture ends.

## The AIY Voice Kit became a browser device

My original plan was to implement everything in Python on the Raspberry Pi inside the old AIY Voice Kit. The archived hardware libraries and older system image made that awkward. Running the same browser application on the Pi was much simpler and kept the example portable.

The browser handled the WebRTC session, while a variation of the page connected the Voice Kit’s button and light to the conversation. The experiment also pointed toward smaller embedded implementations. A full browser is not required in principle—libraries such as Pion, aiortc, and embedded WebRTC stacks can establish the same kind of connection—but it was the fastest way to bring the old hardware back to life.

The [full webrtcHacks guide](https://webrtchacks.com/the-unofficial-guide-to-openai-realtime-webrtc-api/?ref=cogint.ai) includes the live example, complete event walkthrough, source code, security caveats, SDP details, and AIY Voice Kit demonstration.