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

gemini-2.5-flash-native-audio

invited beta Tool callingReasoning

Gemini 2.5 Flash Native Audio is Google's native-audio Live API model, which the model page describes as enabling low-latency, real-time voice and video interactions with Gemini 2.5 Flash: it processes continuous streams of audio, video, or text and answers with immediate, human-like speech rather than chaining a transcriber and a synthesiser.

Input
text audio video $0.5/M
Output
text audio $2/M
Audio input
$3/M
Audio output
$12/M
Knowledge cutoff
2025-01

Benchmarks

gemini-2.5-flash-native-audio: 8 published, but no benchmark it shares with enough other models to compare.

gemini-2.5-flash-native-audio other models measured peer average no peer scored higher
AMI near+far field (WER)
63.8%
Big Bench Audio
71%
BFCL v3 (single-turn, python only)
69.4%

Vendor-published: Amazon OpenAI

Price in context

Where the price sits among 6 comparable models

Input$0.5/M
$0.06 · nova-2-sonic GPT Realtime · $4
Output$2/M
$0.24 · nova-2-sonic GPT Realtime 2.1 · $24

The bar shows how this model’s price compares with every other model of the same kind on Synthorai. The cheapest and the most expensive are named at each end. These are base rates; batch, region and cache-write discounts are on the pricing page.

Specs & limits

Tokens

Context window (vendor spec) 131,072
Max output (vendor spec) 8,192
Knowledge cutoff 2025-01

Thinking

Vendor control thinkingBudget
Default dynamic thinking applied when the request sets nothing
Can be turned off Yes
Thinking behaviour The Live API guide documents this 2.5 Live model as using a token budget rather than a level: dynamic thinking on by default, thinkingBudget 0 to disable.
Parameter reasoning_effort
Values minimal · low · medium · high accepted set is the provider's

Audio

Audio limits
  • Live API session: raw little-endian 16-bit PCM, 16 kHz input and 24 kHz output
  • audio-only sessions capped at 15 minutes (2 minutes with video) unless extended via session management
  • 128k-token session context
Streaming transcription Yes

Realtime

Voices Any voice from the Gemini text-to-speech voice set; native-audio output models switch languages naturally during a conversation.
Session
  • Function calling supported, with NON_BLOCKING function declarations letting the model keep talking while a tool runs
  • VAD interruption cancels and discards the in-flight generation
  • search grounding and thinking supported
  • no caching, structured outputs, code execution or Batch API

Model

Modalities text + audio + video → text + audio

Native-audio Live API model that processes raw audio end to end rather than chaining STT and TTS. Google's model page lists a January 2025 knowledge cutoff and an unusually small 8,192-token output limit alongside the 131,072-token input window.

per Google official docs ↗

Use gemini-2.5-flash-native-audio 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=gemini-2.5-flash-native-audio"
# Send ONLY the Authorization header - the beta protocol is retired.
HEADERS = {"Authorization": "Bearer sk-syn-..."}

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": {
                "type": "realtime",
                "output_modalities": ["audio"],
                "audio": {"output": {"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 gemini-2.5-flash-native-audio

  • Sessions run over a stateful WebSocket, taking raw 16-bit PCM at 16 kHz in and returning it at 24 kHz, and the model accepts audio, video, and text while returning audio and text.
  • Token limits are 131,072 for input and an unusually small 8,192 for output, the session context window is 128k tokens for native-audio models, and audio-only sessions run 15 minutes, or 2 minutes with video, unless extended through session management.
  • Function calling, search grounding, and thinking are supported; caching, structured outputs, code execution, and the Batch API are not.
  • Two capabilities set this generation apart from the newer Live model and are the reason to stay on it: proactive audio, which lets the model decide not to respond when the input is not relevant, and affective dialog, which adapts response style to the expression and tone of the speaker.
  • Asynchronous function calling is also supported here, so a declaration marked non-blocking lets the model keep talking while a tool runs.
  • Voices come from Google's text-to-speech set, native-audio output switches languages naturally during a conversation and does not accept an explicit language code, and the knowledge cutoff is January 2025.
  • Synthorai exposes it through the OpenAI-compatible /v1/realtime WebSocket endpoint used for the rest of its voice catalog.

FAQ

Is the gemini-2.5-flash-native-audio API free to try?

gemini-2.5-flash-native-audio 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 gemini-2.5-flash-native-audio best at?

Low-latency real-time voice and video over the Live API; proactive audio and affective dialog, absent from the newer Live model; audio-only sessions run 15 minutes, two with video. See the About section for the full picture from the vendor's own release notes.

How much does gemini-2.5-flash-native-audio cost?

gemini-2.5-flash-native-audio costs $0.5 per million input tokens and $2 per million output tokens on Synthorai. That is the provider's list price, with no platform markup.

How do I connect to the gemini-2.5-flash-native-audio API?

gemini-2.5-flash-native-audio is a speech-to-speech model: connect over WebSocket to wss://synthorai.io/v1/realtime?model=gemini-2.5-flash-native-audio 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, sending only the Authorization header (the beta protocol is retired).

How do I get access to gemini-2.5-flash-native-audio?

gemini-2.5-flash-native-audio 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="gemini-2.5-flash-native-audio".

Related models

Compare

Every value on this page is transcribed from the vendor's own documentation, linked above, and carries the date it was checked. Prices are compared across the catalogue; specification values that vendors define differently are shown with the difference stated rather than charted. Nothing here is measured by us, and nothing is scored.

Get your API key Compare your cost →