Example: Speech-to-speech translation

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call.sendMediaTo(geminiLiveAPIClient);
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geminiLiveAPIClient.sendMediaTo(calleeCall);

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if (payload.interrupted !== undefined) {
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  geminiLiveAPIClient.clearMediaBuffer();
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}

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if (payload.inputTranscription?.text) Logger.write(`===EN=== ${payload.inputTranscription.text}`);
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if (payload.outputTranscription?.text) Logger.write(`===ES=== ${payload.outputTranscription.text}`);

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/**
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 * Voximplant + Gemini Live API connector demo
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 * Scenario: real-time speech-to-speech translation (English -> Spanish).
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 */
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require(Modules.Gemini);
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require(Modules.ApplicationStorage);
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const SYSTEM_INSTRUCTIONS = `
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You are a REAL-TIME INTERPRETER.
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Task:
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- Translate everything you hear from English to Spanish.
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Rules:
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- Output ONLY the Spanish translation (no English, no explanations, no extra commentary).
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- Preserve meaning, tone, names, numbers, and proper nouns.
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- Keep latency low: translate phrase-by-phrase as soon as you have enough context.
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- Do NOT greet or introduce yourself. Speak ONLY when the caller speaks.
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`;
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const GEMINI_MODEL = "gemini-2.5-flash-native-audio-preview-12-2025";
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VoxEngine.addEventListener(AppEvents.CallAlerting, async ({call}) => {
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    let voiceAIClient;
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    let calleeCall;
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    let terminated = false;
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    const terminate = () => {
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        if (terminated) return;
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        terminated = true;
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        try {
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            voiceAIClient?.close();
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        } catch (error) {
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            Logger.write(error);
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        }
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        try {
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            calleeCall?.hangup();
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        } catch (error) {
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            Logger.write(error);
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        }
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        try {
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            call.hangup();
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        } catch (error) {
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            Logger.write(error);
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        }
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        VoxEngine.terminate();
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    };
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    call.answer();
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    call.record({hd_audio: true, stereo: true});
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    call.addEventListener(CallEvents.Disconnected, terminate);
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    call.addEventListener(CallEvents.Failed, terminate);
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    const geminiApiKey = (await ApplicationStorage.get("GEMINI_API_KEY")).value;
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    // const calleeNumber = (await ApplicationStorage.get("CALLEE_NUMBER")).value;
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    // const pstnCallerId = (await ApplicationStorage.get("PSTN_CALLER_ID")).value;
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    // calleeCall = VoxEngine.callPSTN(calleeNumber, pstnCallerId);
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    calleeCall = VoxEngine.callUser("callee");
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    calleeCall.addEventListener(CallEvents.Disconnected, terminate);
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    calleeCall.addEventListener(CallEvents.Failed, terminate);
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    calleeCall.addEventListener(CallEvents.Connected, async () => {
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        calleeCall.record({hd_audio: true, stereo: true});
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        // Optional prompts to make the demo obvious on recordings.
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        call.say("Connected. Speak in English. The other party will hear Spanish.");
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        calleeCall.say("Connected. You will hear Spanish translation in real time.");
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        const GEMINI_CONNECT_CONFIG = {
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            responseModalities: ["AUDIO"],
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            thinkingConfig: {thinkingBudget: 0},
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            realtimeInputConfig: {
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                automaticActivityDetection: {
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                    disabled: false,
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                    prefixPaddingMs: 20,
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                    silenceDurationMs: 200,
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                },
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            },
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            speechConfig: {
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                voiceConfig: {
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                    prebuiltVoiceConfig: {voiceName: "Achird"},
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                },
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            },
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            // inputAudioTranscription: {},
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            // outputAudioTranscription: {},
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            systemInstruction: {
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                parts: [{text: SYSTEM_INSTRUCTIONS}],
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            },
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        };
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        try {
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            voiceAIClient = await Gemini.createLiveAPIClient({
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                apiKey: geminiApiKey,
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                model: GEMINI_MODEL,
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                backend: Gemini.Backend.GEMINI_API,
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                connectConfig: GEMINI_CONNECT_CONFIG,
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                onWebSocketClose: (event) => {
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                    Logger.write("===Gemini.WebSocket.Close===");
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                    if (event) Logger.write(JSON.stringify(event));
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                    terminate();
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                },
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            });
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            // Caller (English) -> Gemini -> Callee (Spanish)
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            call.sendMediaTo(voiceAIClient);
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            voiceAIClient.sendMediaTo(calleeCall);
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            voiceAIClient.addEventListener(Gemini.LiveAPIEvents.SetupComplete, (event) => {
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                Logger.write("===Gemini.LiveAPIEvents.SetupComplete===");
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                if (event?.data) Logger.write(JSON.stringify(event.data));
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            });
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            voiceAIClient.addEventListener(Gemini.LiveAPIEvents.ServerContent, (event) => {
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                const payload = event?.data?.payload || {};
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                if (payload.inputTranscription?.text) {
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                    Logger.write(`===EN=== ${payload.inputTranscription.text}`);
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                }
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                if (payload.outputTranscription?.text) {
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                    Logger.write(`===ES=== ${payload.outputTranscription.text}`);
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                }
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                if (payload.interrupted !== undefined) {
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                    Logger.write("===BARGE-IN=== Gemini.LiveAPIEvents.ServerContent");
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                    voiceAIClient.clearMediaBuffer();
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                }
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            });
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            [
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                Gemini.LiveAPIEvents.SetupComplete,
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                Gemini.LiveAPIEvents.ServerContent,
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                Gemini.LiveAPIEvents.ConnectorInformation,
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                Gemini.LiveAPIEvents.Unknown,
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                Gemini.Events.WebSocketMediaStarted,
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                Gemini.Events.WebSocketMediaEnded,
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            ].forEach((eventName) => {
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                voiceAIClient.addEventListener(eventName, (event) => {
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                    Logger.write(`===${event.name}===`);
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                    if (event?.data) Logger.write(JSON.stringify(event.data));
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                });
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            });
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        } catch (error) {
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            Logger.write("===SOMETHING_WENT_WRONG===");
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            Logger.write(error);
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            terminate();
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        }
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    });
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});