Get started with the Gemini Live API using Firebase AI Logic


The Gemini Live API enables low-latency, real-time voice and video interactions with a Gemini model that are bidirectional.

The Live API and its special family of models can process continuous streams of audio, video, or text to deliver immediate, human-like spoken responses, creating a natural conversational experience for your users.

This page describes how to get started with the most common capability — streaming audio input and output, but the Live API supports many different capabilities and configuration options.

The Live API is a stateful API that creates a WebSocket connection to establish a session between the client and the Gemini server. For details, see the Live API reference documentation (Gemini Developer API | Vertex AI Gemini API).

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Check out helpful resources

Before you begin

If you haven't already, complete the getting started guide, which describes how to set up your Firebase project, connect your app to Firebase, add the SDK, initialize the backend service for your chosen Gemini API provider, and create a LiveModel instance.

You can prototype with prompts and the Live API in Google AI Studio or Vertex AI Studio.

Models that support this capability

  • Gemini Developer API

    • gemini-2.5-flash-native-audio-preview-09-2025
  • Vertex AI Gemini API

    • gemini-live-2.5-flash-preview-native-audio-09-2025

    When using the Vertex AI Gemini API, the Live API models are only available in the us-central1 location. .

Stream audio input and output

Click your Gemini API provider to view provider-specific content and code on this page.

The following example shows the basic implementation to send streamed audio input and receive streamed audio output.

For additional options and capabilities for the Live API, review the "What else can you do?" section later on this page.

Swift

To use the Live API, create a LiveModel instance and set the response modality to audio.


import FirebaseAILogic

// Initialize the Gemini Developer API backend service
// Create a `liveModel` instance with a model that supports the Live API
let liveModel = FirebaseAI.firebaseAI(backend: .googleAI()).liveModel(
  modelName: "gemini-2.5-flash-native-audio-preview-09-2025",
  // Configure the model to respond with audio
  generationConfig: LiveGenerationConfig(
    responseModalities: [.audio]
  )
)

do {
  let session = try await liveModel.connect()

  // Load the audio file, or tap a microphone
  guard let audioFile = NSDataAsset(name: "audio.pcm") else {
    fatalError("Failed to load audio file")
  }

  // Provide the audio data
  await session.sendAudioRealtime(audioFile.data)

  var outputText = ""
  for try await message in session.responses {
    if case let .content(content) = message.payload {
      content.modelTurn?.parts.forEach { part in
        if let part = part as? InlineDataPart, part.mimeType.starts(with: "audio/pcm") {
          // Handle 16bit pcm audio data at 24khz
          playAudio(part.data)
        }
      }
      // Optional: if you don't require to send more requests.
      if content.isTurnComplete {
        await session.close()
      }
    }
  }
} catch {
  fatalError(error.localizedDescription)
}

Kotlin

To use the Live API, create a LiveModel instance and set the response modality to AUDIO.


// Initialize the Gemini Developer API backend service
// Create a `liveModel` instance with a model that supports the Live API
val liveModel = Firebase.ai(backend = GenerativeBackend.googleAI()).liveModel(
    modelName = "gemini-2.5-flash-native-audio-preview-09-2025",
    // Configure the model to respond with audio
    generationConfig = liveGenerationConfig {
        responseModality = ResponseModality.AUDIO
   }
)

val session = liveModel.connect()

// This is the recommended approach.
// However, you can create your own recorder and handle the stream.
session.startAudioConversation()

Java

To use the Live API, create a LiveModel instance and set the response modality to AUDIO.


ExecutorService executor = Executors.newFixedThreadPool(1);
// Initialize the Gemini Developer API backend service
// Create a `liveModel` instance with a model that supports the Live API
LiveGenerativeModel lm = FirebaseAI.getInstance(GenerativeBackend.googleAI()).liveModel(
        "gemini-2.5-flash-native-audio-preview-09-2025",
        // Configure the model to respond with audio
        new LiveGenerationConfig.Builder()
                .setResponseModality(ResponseModality.AUDIO)
                .build()
);
LiveModelFutures liveModel = LiveModelFutures.from(lm);

ListenableFuture<LiveSession> sessionFuture =  liveModel.connect();

Futures.addCallback(sessionFuture, new FutureCallback<LiveSession>() {
    @Override
    public void onSuccess(LiveSession ses) {
	 LiveSessionFutures session = LiveSessionFutures.from(ses);
        session.startAudioConversation();
    }
    @Override
    public void onFailure(Throwable t) {
        // Handle exceptions
    }
}, executor);

Web

To use the Live API, create a LiveGenerativeModel instance and set the response modality to AUDIO.


import { initializeApp } from "firebase/app";
import { getAI, getLiveGenerativeModel, GoogleAIBackend, ResponseModality } from "firebase/ai";

// TODO(developer) Replace the following with your app's Firebase configuration
// See: https://firebase.google.com/docs/web/learn-more#config-object
const firebaseConfig = {
  // ...
};

// Initialize FirebaseApp
const firebaseApp = initializeApp(firebaseConfig);

// Initialize the Gemini Developer API backend service
const ai = getAI(firebaseApp, { backend: new GoogleAIBackend() });

// Create a `LiveGenerativeModel` instance with a model that supports the Live API
const liveModel = getLiveGenerativeModel(ai, {
  model: "gemini-2.5-flash-native-audio-preview-09-2025",
  // Configure the model to respond with audio
  generationConfig: {
    responseModalities: [ResponseModality.AUDIO],
  },
});

const session = await liveModel.connect();

// Start the audio conversation
const audioConversationController = await startAudioConversation(session);

// ... Later, to stop the audio conversation
// await audioConversationController.stop()

Dart

To use the Live API, create a LiveGenerativeModel instance and set the response modality to audio.


import 'package:firebase_ai/firebase_ai.dart';
import 'package:firebase_core/firebase_core.dart';
import 'firebase_options.dart';
import 'package:your_audio_recorder_package/your_audio_recorder_package.dart';

late LiveModelSession _session;
final _audioRecorder = YourAudioRecorder();

await Firebase.initializeApp(
  options: DefaultFirebaseOptions.currentPlatform,
);

// Initialize the Gemini Developer API backend service
// Create a `liveGenerativeModel` instance with a model that supports the Live API
final liveModel = FirebaseAI.googleAI().liveGenerativeModel(
  model: 'gemini-2.5-flash-native-audio-preview-09-2025',
  // Configure the model to respond with audio
  liveGenerationConfig: LiveGenerationConfig(
    responseModalities: [ResponseModalities.audio],
  ),
);

_session = await liveModel.connect();

final audioRecordStream = _audioRecorder.startRecordingStream();
// Map the Uint8List stream to InlineDataPart stream
final mediaChunkStream = audioRecordStream.map((data) {
  return InlineDataPart('audio/pcm', data);
});
await _session.startMediaStream(mediaChunkStream);

// In a separate thread, receive the audio response from the model
await for (final message in _session.receive()) {
   // Process the received message
}

Unity

To use the Live API, create a LiveModel instance and set the response modality to Audio.


using Firebase;
using Firebase.AI;

async Task SendTextReceiveAudio() {
  // Initialize the Gemini Developer API backend service
  // Create a `LiveModel` instance with a model that supports the Live API
  var liveModel = FirebaseAI.GetInstance(FirebaseAI.Backend.GoogleAI()).GetLiveModel(
      modelName: "gemini-2.5-flash-native-audio-preview-09-2025",
      // Configure the model to respond with audio
      liveGenerationConfig: new LiveGenerationConfig(
          responseModalities: new[] { ResponseModality.Audio })
    );

  LiveSession session = await liveModel.ConnectAsync();

  // Start a coroutine to send audio from the Microphone
  var recordingCoroutine = StartCoroutine(SendAudio(session));

  // Start receiving the response
  await ReceiveAudio(session);
}

IEnumerator SendAudio(LiveSession liveSession) {
  string microphoneDeviceName = null;
  int recordingFrequency = 16000;
  int recordingBufferSeconds = 2;

  var recordingClip = Microphone.Start(microphoneDeviceName, true,
                                       recordingBufferSeconds, recordingFrequency);

  int lastSamplePosition = 0;
  while (true) {
    if (!Microphone.IsRecording(microphoneDeviceName)) {
      yield break;
    }

    int currentSamplePosition = Microphone.GetPosition(microphoneDeviceName);

    if (currentSamplePosition != lastSamplePosition) {
      // The Microphone uses a circular buffer, so we need to check if the
      // current position wrapped around to the beginning, and handle it
      // accordingly.
      int sampleCount;
      if (currentSamplePosition > lastSamplePosition) {
        sampleCount = currentSamplePosition - lastSamplePosition;
      } else {
        sampleCount = recordingClip.samples - lastSamplePosition + currentSamplePosition;
      }

      if (sampleCount > 0) {
        // Get the audio chunk
        float[] samples = new float[sampleCount];
        recordingClip.GetData(samples, lastSamplePosition);

        // Send the data, discarding the resulting Task to avoid the warning
        _ = liveSession.SendAudioAsync(samples);

        lastSamplePosition = currentSamplePosition;
      }
    }

    // Wait for a short delay before reading the next sample from the Microphone
    const float MicrophoneReadDelay = 0.5f;
    yield return new WaitForSeconds(MicrophoneReadDelay);
  }
}

Queue audioBuffer = new();

async Task ReceiveAudio(LiveSession liveSession) {
  int sampleRate = 24000;
  int channelCount = 1;

  // Create a looping AudioClip to fill with the received audio data
  int bufferSamples = (int)(sampleRate * channelCount);
  AudioClip clip = AudioClip.Create("StreamingPCM", bufferSamples, channelCount,
                                    sampleRate, true, OnAudioRead);

  // Attach the clip to an AudioSource and start playing it
  AudioSource audioSource = GetComponent();
  audioSource.clip = clip;
  audioSource.loop = true;
  audioSource.Play();

  // Start receiving the response
  await foreach (var message in liveSession.ReceiveAsync()) {
    // Process the received message
    foreach (float[] pcmData in message.AudioAsFloat) {
      lock (audioBuffer) {
        foreach (float sample in pcmData) {
          audioBuffer.Enqueue(sample);
        }
      }
    }
  }
}

// This method is called by the AudioClip to load audio data.
private void OnAudioRead(float[] data) {
  int samplesToProvide = data.Length;
  int samplesProvided = 0;

  lock(audioBuffer) {
    while (samplesProvided < samplesToProvide && audioBuffer.Count > 0) {
      data[samplesProvided] = audioBuffer.Dequeue();
      samplesProvided++;
    }
  }

  while (samplesProvided < samplesToProvide) {
    data[samplesProvided] = 0.0f;
    samplesProvided++;
  }
}



Pricing and token counting

You can find pricing information for the Live API models in the documentation for your chosen Gemini API provider: Gemini Developer API | Vertex AI Gemini API.

Regardless of your Gemini API provider, the Live API does not support the Count Tokens API.



What else can you do?

  • Check out the full suite of capabilities for the Live API, like streaming various input modalities (audio, text, or video + audio).

  • Customize your implementation by using various configuration options, like adding transcription or setting the response voice.

  • Supercharge your implementation by giving the model access to tools, like function calling and grounding with Google Search. Official documentation for using tools with the Live API is coming soon!

  • Learn about limits and specifications, for using the Live API, like session length, rate limits, supported languages, etc.