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@adrper79-dot/telephony

Voice pipeline for inbound/outbound calls: Deepgram speech-to-text, ElevenLabs text-to-speech, Telnyx call control webhooks, and a VoiceSession orchestrator. Depends on @adrper79-dot/errors, @adrper79-dot/logger, and @adrper79-dot/llm.

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Installation

npm install @adrper79-dot/telephony

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Secrets required

wrangler secret put TELNYX_API_KEY
wrangler secret put DEEPGRAM_API_KEY
wrangler secret put ELEVENLABS_API_KEY

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API

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transcribeAudio(audioBuffer, env, opts?)

Transcribes audio using Deepgram Nova-2. 
function transcribeAudio(
  audioBuffer: Uint8Array,
  env: { DEEPGRAM_API_KEY: string },
  opts?: { language?: string; model?: string },
): Promise<string>;

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synthesizeSpeech(text, env, opts?)

Synthesizes speech using ElevenLabs. Returns a Uint8Array of MP3 audio. 
function synthesizeSpeech(
  text: string,
  env: { ELEVENLABS_API_KEY: string },
  opts?: { voiceId?: string; modelId?: string },
): Promise<Uint8Array>;

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verifyTelnyxWebhook(request, secret)

Verifies a Telnyx webhook signature. Throws ValidationError on failure. 
function verifyTelnyxWebhook(
  request: Request,
  secret: string,
): Promise<TelnyxEvent>;

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VoiceSession

Orchestrates a full conversation turn: transcribe → LLM → synthesize. 
class VoiceSession {
  constructor(config: VoiceSessionConfig);
  processAudio(audioBuffer: Uint8Array): Promise<Uint8Array>; // returns TTS audio
  getHistory(): LLMMessage[];
  end(): void;
}

interface VoiceSessionConfig {
  callId: string;
  direction: 'inbound' | 'outbound';
  voiceId: string;
  language?: string;
  systemPrompt: string;
  env: {
    TELNYX_API_KEY: string;
    DEEPGRAM_API_KEY: string;
    ELEVENLABS_API_KEY: string;
    ANTHROPIC_API_KEY: string;
    GROK_API_KEY: string;
    GROQ_API_KEY: string;
  };
}

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Example

import { VoiceSession, verifyTelnyxWebhook } from '@adrper79-dot/telephony';

app.post('/webhook/telnyx', async (c) => {
  const event = await verifyTelnyxWebhook(c.req.raw, c.env.TELNYX_API_KEY);

  if (event.data.event_type === 'call.answered') {
    const session = new VoiceSession({
      callId: event.data.payload.call_control_id,
      direction: 'inbound',
      voiceId: 'eleven-turbo-v2',
      systemPrompt: 'You are a friendly receptionist for Acme Corp.',
      env: c.env,
    });
    // Store session in Durable Object or KV by callId
  }

  return c.json({ received: true });
});