Example: Placing an outbound call

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{"destination":"+15551234567","callerId":"+15557654321"}

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call = VoxEngine.callPSTN(destination, callerId);
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call.addEventListener(CallEvents.Connected, async () => {
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  // ...
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});

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voiceAIClient = await Ultravox.createWebSocketAPIClient({ ... });
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VoxEngine.sendMediaBetween(call, voiceAIClient);

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voiceAIClient.addEventListener(Ultravox.WebSocketAPIEvents.Transcript, (event) => {
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  const { role } = event?.data?.payload || {};
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  if (role === "user") voiceAIClient.clearMediaBuffer();
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});

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/**
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 * Voximplant + Ultravox WebSocket API connector demo
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 * Scenario: place an outbound call and bridge it to Ultravox after answer.
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 */
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require(Modules.Ultravox);
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require(Modules.ApplicationStorage);
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const SYSTEM_PROMPT = `You are a helpful phone assistant for Voximplant callers.
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Keep responses short and telephony-friendly (1–2 sentences).`;
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// -------------------- Ultravox WebSocket API settings --------------------
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const MODEL = "ultravox-v0.7";
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const VOICE_NAME = "Mark";
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const DEFAULT_CALL_DURATION_MS = 40000;
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function parseCustomData() {
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    const raw = VoxEngine.customData();
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    if (!raw) return {};
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    try {
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        return JSON.parse(raw);
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    } catch (error) {
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        Logger.write("===CUSTOM_DATA_PARSE_FAILED===");
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        Logger.write(error);
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        return {};
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    }
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}
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VoxEngine.addEventListener(AppEvents.Started, async () => {
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    let voiceAIClient;
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    const {
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        destination,
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        callerId,
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        callDurationMs = DEFAULT_CALL_DURATION_MS,
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    } = parseCustomData();
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    if (!destination || !callerId) {
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        Logger.write("===MISSING_CUSTOM_DATA===");
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        Logger.write(JSON.stringify({destination, callerId}));
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        VoxEngine.terminate();
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        return;
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    }
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    // Place the outbound call (primary path: PSTN)
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    let call = VoxEngine.callPSTN(destination, callerId);
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    // Alternative outbound paths (uncomment to use):
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    // call = VoxEngine.callUser({ username: "callee", callerid: callerId });
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    // call = VoxEngine.callSIP(`sip:${destination}@your-sip-domain`, callerId);
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    // call = VoxEngine.callWhatsappUser({ number: destination, callerid: callerId });
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    let hangupTimer;
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    // Termination functions - add cleanup and logging as needed
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    const terminate = () => {
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        if (hangupTimer) clearTimeout(hangupTimer);
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        voiceAIClient?.close();
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        VoxEngine.terminate();
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    };
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    call.addEventListener(CallEvents.Disconnected, terminate);
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    call.addEventListener(CallEvents.Failed, terminate);
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    call.addEventListener(CallEvents.Connected, async () => {
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        hangupTimer = setTimeout(() => call.hangup(), Number(callDurationMs));
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        const apiKey = (await ApplicationStorage.get("ULTRAVOX_API_KEY")).value;
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        const authorizations = {
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            "X-API-Key": apiKey,
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        };
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        // Create client and wire media after the callee answers
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        const webSocketAPIClientParameters = {
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            endpoint: Ultravox.HTTPEndpoint.CREATE_CALL,
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            authorizations,
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            body: {
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                systemPrompt: SYSTEM_PROMPT,
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                model: MODEL,
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                voice: VOICE_NAME,
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            },
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            onWebSocketClose: (event) => {
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                Logger.write("===ULTRAVOX_WEBSOCKET_CLOSED===");
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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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        try {
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            voiceAIClient = await Ultravox.createWebSocketAPIClient(
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                webSocketAPIClientParameters,
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            );
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            VoxEngine.sendMediaBetween(call, voiceAIClient);
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            // ---------------------- Event handlers -----------------------
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            // Barge-in: keep conversation responsive and capture transcript
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            voiceAIClient.addEventListener(
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                Ultravox.WebSocketAPIEvents.Transcript,
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                (event) => {
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                    const payload = event?.data?.payload || event?.data || {};
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                    const role = payload.role;
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                    const text = payload.text || payload.delta;
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                    if (role && text) Logger.write(`===TRANSCRIPT=== ${role}: ${text}`);
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                    if (role === "user") voiceAIClient.clearMediaBuffer();
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                },
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            );
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            voiceAIClient.addEventListener(
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                Ultravox.WebSocketAPIEvents.PlaybackClearBuffer,
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                () => voiceAIClient.clearMediaBuffer(),
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            );
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            // Consolidated "log-only" handlers - key Ultravox/VoxEngine debugging events
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            [
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                Ultravox.WebSocketAPIEvents.ConnectorInformation,
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                Ultravox.WebSocketAPIEvents.HTTPResponse,
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                Ultravox.WebSocketAPIEvents.State,
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                Ultravox.WebSocketAPIEvents.Debug,
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                Ultravox.WebSocketAPIEvents.WebSocketError,
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                Ultravox.WebSocketAPIEvents.Unknown,
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                Ultravox.Events.WebSocketMediaStarted,
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                Ultravox.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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                    Logger.write(JSON.stringify(event));
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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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});