🎁 New Sign up free, 10 calls on us. Up to $1, no card needed.

GPT Realtime 2.1 Released 2026-07-06

OpenAI invited beta realtime audio
Input$4/M
Output$24/M
Audio input$32/M
Audio output$64/M
Cache read$0.4/M
Knowledge cutoff2024-09

Provider list prices: no platform markup, pay-as-you-go. These are official list prices. Logged-in customers may see effective prices including workspace discounts on /console/pricing. Effective input at a 70% cache-hit rate:$1.48/M. Automatic prefix caching once a prompt passes the minimum length, with no code changes; cached reads are discounted (up to 90% on current models) and there is no write fee.

Use GPT Realtime 2.1 in 30 seconds

OpenAI Realtime-compatible: connect over WebSocket and stream audio in, audio out. WS /v1/realtime

import asyncio, base64, json, websockets

URL = "wss://synthorai.io/v1/realtime?model=gpt-realtime-2.1"
HEADERS = {"Authorization": "Bearer sk-syn-...", "OpenAI-Beta": "realtime=v1"}

async def main():
    async with websockets.connect(URL, additional_headers=HEADERS) as ws:
        # 1) configure the speech-to-speech session
        await ws.send(json.dumps({
            "type": "session.update",
            "session": {"modalities": ["audio", "text"], "voice": "alloy"},
        }))
        # 2) send input audio (base64 PCM16), then request a spoken reply
        await ws.send(json.dumps({"type": "input_audio_buffer.append", "audio": pcm16_b64}))
        await ws.send(json.dumps({"type": "input_audio_buffer.commit"}))
        await ws.send(json.dumps({"type": "response.create"}))
        # 3) stream the model's audio (and text) back
        async for raw in ws:
            ev = json.loads(raw)
            if ev["type"] == "response.audio.delta":
                play(base64.b64decode(ev["delta"]))   # audio out
            elif ev["type"] == "response.done":
                break

asyncio.run(main())

About GPT Realtime 2.1

Flagship realtime tier for production voice agents
Improved interruption, noise, and alphanumeric handling
Configurable reasoning effort with tool use

GPT Realtime 2.1 is the flagship of OpenAI's realtime speech-to-speech family, announced as an updated realtime reasoning model with improved alphanumeric recognition, silence and noise handling, and interruption behavior.

  • It expands the family to a 128K-token context window with 32K max output tokens, and supports configurable reasoning effort, instruction following, and tool use for complex voice-agent workflows.
  • Audio and text tokens are billed at separate per-token rates, with discounted cached input.
  • On Synthorai it is served through the OpenAI-compatible /v1/realtime WebSocket endpoint, so applications built on the official Realtime SDKs work unchanged.

Specs & limits

Max output (vendor spec)32,000
Modalitiesaudio + text → audio + text
Featuresrealtime · speech-to-speech
NotableUpdated realtime reasoning model with improved alphanumeric recognition, silence and noise handling, and interruption behavior; configurable reasoning effort and tool use for voice-agent workflows; 128k context.
Prompt cachingautomatic · min 1,024-token prefix · TTL 5–10m, up to 1h

per OpenAI official docs ↗

FAQ

Is the GPT Realtime 2.1 API free to try?

GPT Realtime 2.1 is currently in invited beta: access is application-based rather than open signup. Apply from the Synthorai console; once approved, standard pay-as-you-go pricing applies with no subscription.

What is GPT Realtime 2.1 best at?

Flagship realtime tier for production voice agents, plus improved interruption, noise, and alphanumeric handling and configurable reasoning effort with tool use. See the About section for the full picture from the vendor's own release notes.

How much does GPT Realtime 2.1 cost?

GPT Realtime 2.1 costs $4 per million input tokens and $24 per million output tokens on Synthorai. That is the provider's list price, with no platform markup. Cached input tokens bill at $0.4/M.

How do I connect to the GPT Realtime 2.1 API?

GPT Realtime 2.1 is a speech-to-speech model: connect over WebSocket to wss://synthorai.io/v1/realtime?model=gpt-realtime-2.1 with the OpenAI Realtime SDK (or a raw WebSocket) and stream audio in, audio out. It is not a POST /v1/audio/transcriptions file upload. Authenticate with your sk-syn key and mirror the OpenAI-Beta header.

How do I get access to GPT Realtime 2.1?

GPT Realtime 2.1 is in invited beta: request access from the Synthorai console. Once approved it works like every other model: point your OpenAI SDK at base_url="https://synthorai.io/v1" and set model="gpt-realtime-2.1".

Related models

Get your free API key Compare your cost →