Processing Genesys Cloud Real-Time Transcription Streams with Node.js

What You Will Build

• A Node.js service that connects to the Genesys Cloud Speech API WebSocket to stream audio and receive real-time transcription updates.
• The application uses the @genesyscloud/platform-client-sdk for REST operations and the ws library for bidirectional WebSocket communication.
• The code is implemented in modern JavaScript (ESM) with comprehensive error handling, retry logic, and metric logging.

Prerequisites

• OAuth 2.0 Client Credentials or JWT flow with scopes: speech:transcription:readwrite, interaction:write, speech:glossary:read
• Genesys Cloud Platform Client SDK v9.0+ (npm install @genesyscloud/platform-client-sdk)
• Node.js v18+ with native fetch support
• External dependencies: ws, axios, dotenv
• Access to a Genesys Cloud organization with Speech API enabled and a valid transcription configuration ID

Authentication Setup

The Genesys Cloud Platform requires a valid JWT or Bearer token for all REST and WebSocket operations. The SDK handles token acquisition and automatic refresh, but you must cache the token for WebSocket authorization headers.

import { PlatformClient } from '@genesyscloud/platform-client-sdk';
import dotenv from 'dotenv';

dotenv.config();

const platformClient = new PlatformClient();

async function initializeAuth() {
  try {
    await platformClient.init({
      clientId: process.env.GENESYS_CLIENT_ID,
      clientSecret: process.env.GENESYS_CLIENT_SECRET,
      environment: process.env.GENESYS_ENVIRONMENT,
      loginOptions: {
        grantType: 'client_credentials',
        scopes: ['speech:transcription:readwrite', 'interaction:write', 'speech:glossary:read']
      }
    });

    const tokenInfo = await platformClient.auth.getAccessToken();
    console.log('Authentication successful. Token expires at:', tokenInfo.expiresAt);
    return tokenInfo;
  } catch (error) {
    if (error.status === 401) {
      throw new Error('Invalid client credentials or missing scopes');
    }
    if (error.status === 403) {
      throw new Error('Client lacks required permissions. Verify scopes.');
    }
    throw error;
  }
}

The platformClient.auth.getAccessToken() call returns a token object. Store the accessToken value for WebSocket handshake headers. The SDK automatically refreshes tokens before expiration, but you must poll platformClient.auth.getAccessToken() if your runtime lifecycle exceeds the default 3600-second window.

Implementation

Step 1: Initialize SDK and Cache Glossary Definitions

Transcription glossaries improve accuracy for domain-specific terminology. Fetching them on every message causes unnecessary latency. Cache them in memory and refresh periodically.

import axios from 'axios';

const glossaryCache = new Map();
const GLOSSARY_REFRESH_MS = 300000; // 5 minutes

async function fetchAndCacheGlossaries(accessToken, environment) {
  const baseUrl = `https://api.${environment}.mypurecloud.com`;
  let nextPageUrl = `${baseUrl}/api/v2/speech/glossaries?pageSize=100`;

  while (nextPageUrl) {
    try {
      const response = await axios.get(nextPageUrl, {
        headers: { Authorization: `Bearer ${accessToken}` },
        timeout: 10000
      });

      response.data.entities.forEach(glossary => {
        glossaryCache.set(glossary.id, {
          name: glossary.name,
          terms: glossary.terms,
          lastUpdated: new Date()
        });
      });

      nextPageUrl = response.data.nextPage;
    } catch (error) {
      if (error.response?.status === 429) {
        const retryAfter = parseInt(error.response.headers['retry-after'] || '2', 10);
        await new Promise(resolve => setTimeout(resolve, retryAfter * 1000));
        continue;
      }
      throw error;
    }
  }
  console.log(`Cached ${glossaryCache.size} glossaries.`);
}

Pagination is handled by following the nextPage cursor until it returns null. The 429 retry logic uses exponential backoff via the retry-after header. Cache invalidation should trigger when transcription configurations change.

Step 2: Establish WebSocket Connection and Synchronize Audio Text

The Speech API WebSocket endpoint accepts audio payloads and returns transcription updates. You must send a subscription frame first, then pipe PCM audio chunks at 16kHz.

import WebSocket from 'ws';

const SPEECH_WS_URL = `wss://api.${process.env.GENESYS_ENVIRONMENT}.mypurecloud.com/api/v2/speech/transcriptions/stream`;

function createTranscriptionStream(accessToken, transcriptionId) {
  const ws = new WebSocket(SPEECH_WS_URL, {
    headers: { Authorization: `Bearer ${accessToken}` }
  });

  ws.on('open', () => {
    const subscribePayload = {
      type: 'subscribe',
      transcriptionId: transcriptionId,
      audioFormat: 'pcm',
      sampleRate: 16000,
      channels: 1
    };
    ws.send(JSON.stringify(subscribePayload));
    console.log('WebSocket connected. Subscription sent.');
  });

  ws.on('error', (error) => {
    console.error('WebSocket error:', error.message);
  });

  ws.on('close', (code, reason) => {
    console.log(`WebSocket closed. Code: ${code}, Reason: ${reason}`);
  });

  return ws;
}

The subscription payload defines the audio format. Genesys Cloud expects raw PCM data. You must send audio chunks as binary frames. The WebSocket maintains a bidirectional channel: you write audio, the platform streams JSON transcription updates.

Step 3: Parse Partial Segments and Apply Corrections and Confidence Filtering

Transcription messages arrive as JSON. Partial messages update frequently. You must filter low-confidence hypotheses and apply client-side punctuation and capitalization before finalizing text.

const CONFIDENCE_THRESHOLD = 0.75;

function processTranscriptMessage(rawText, words, isPartial) {
  if (!words || words.length === 0) return { text: '', speaker: '', filtered: false };

  const filteredWords = words.filter(w => (w.confidence || 0) >= CONFIDENCE_THRESHOLD);
  const filteredText = filteredWords.map(w => w.text).join(' ');

  if (filteredText.length === 0) return { text: '', speaker: '', filtered: true };

  let correctedText = filteredText;

  if (!isPartial) {
    correctedText = correctedText.charAt(0).toUpperCase() + correctedText.slice(1);
    correctedText = correctedText.replace(/([.!?])\s+/g, '$1 ');
    correctedText = correctedText.replace(/\s+([,;:])/g, '$1');
  }

  return { text: correctedText, speaker: words[0]?.speaker || 'unknown', filtered: false };
}

The confidence field represents model certainty. Words below the threshold are dropped to prevent hallucinated terms. Punctuation correction runs only on isPartial === false messages to avoid rewriting live streams. The speaker field maps to the audio channel source.

Step 4: Handle Speaker Diarization and Update Conversation Variables

Genesys Cloud diarization tags each word object with a speaker identifier. Use this to isolate agent versus customer utterances. When a target phrase appears, update the conversation via the Interaction API.

async function updateConversationVariable(conversationId, accessToken, environment, key, value) {
  const baseUrl = `https://api.${environment}.mypurecloud.com`;
  const url = `${baseUrl}/api/v2/interactions/conversations/${conversationId}`;

  const payload = {
    custom: {
      [key]: value
    }
  };

  let attempts = 0;
  const maxAttempts = 3;

  while (attempts < maxAttempts) {
    try {
      const response = await axios.patch(url, payload, {
        headers: { Authorization: `Bearer ${accessToken}`, 'Content-Type': 'application/json' },
        timeout: 8000
      });

      if (response.status === 200) {
        console.log(`Conversation variable ${key} updated successfully.`);
        return response.data;
      }
    } catch (error) {
      if (error.response?.status === 429) {
        attempts++;
        const delay = Math.pow(2, attempts) * 1000;
        console.warn(`Rate limited. Retrying in ${delay}ms...`);
        await new Promise(resolve => setTimeout(resolve, delay));
        continue;
      }
      if (error.response?.status === 404) {
        throw new Error(`Conversation ${conversationId} not found.`);
      }
      throw error;
    }
  }
  throw new Error('Max retry attempts reached for conversation update.');
}

function detectPhraseAndRoute(text, speaker, conversationId, accessToken, environment) {
  const normalizedText = text.toLowerCase();
  if (normalizedText.includes('pricing') && speaker === 'customer') {
    updateConversationVariable(conversationId, accessToken, environment, 'customer_intent', 'pricing_inquiry');
  }
  if (normalizedText.includes('transfer') && speaker === 'agent') {
    updateConversationVariable(conversationId, accessToken, environment, 'agent_action', 'initiated_transfer');
  }
}

The Interaction API PATCH endpoint merges custom variables without overwriting existing data. The retry loop handles 429 rate limits with exponential backoff. Speaker diarization ensures you only trigger logic for the correct participant.

Step 5: Log Latency Metrics and Expose Transcript Diff Tool

Latency measurement compares audio capture timestamps against transcript arrival times. A diff tool compares partial and final transcript states for quality review.

const latencyMetrics = [];

function logTranscriptionLatency(audioTimestamp, transcriptTimestamp) {
  const latencyMs = transcriptTimestamp - audioTimestamp;
  latencyMetrics.push({
    timestamp: new Date().toISOString(),
    latencyMs: latencyMs,
    percentile: latencyMetrics.length > 0 ? Math.min(100, Math.round((latencyMs / 1000) * 100)) : 0
  });

  if (latencyMetrics.length > 100) {
    latencyMetrics.shift();
  }

  const avgLatency = latencyMetrics.reduce((sum, m) => sum + m.latencyMs, 0) / latencyMetrics.length;
  console.log(`Transcription latency: ${latencyMs.toFixed(2)}ms | Average: ${avgLatency.toFixed(2)}ms`);
}

function generateTranscriptDiff(partialText, finalText) {
  const partialWords = partialText.split(/\s+/);
  const finalWords = finalText.split(/\s+/);
  const diff = [];

  const maxLength = Math.max(partialWords.length, finalWords.length);
  for (let i = 0; i < maxLength; i++) {
    const p = partialWords[i] || '';
    const f = finalWords[i] || '';
    if (p !== f) {
      diff.push({ index: i, removed: p, added: f });
    }
  }

  return {
    totalChanges: diff.length,
    changes: diff,
    partialLength: partialWords.length,
    finalLength: finalWords.length
  };
}

The latency logger maintains a sliding window of 100 samples. The diff tool performs a word-level comparison. You can expose the diff function via an HTTP endpoint for administrative review. Both utilities run synchronously to avoid blocking the WebSocket event loop.

Complete Working Example

The following module combines all components into a production-ready service. Replace environment variables with your credentials before execution.

import { PlatformClient } from '@genesyscloud/platform-client-sdk';
import WebSocket from 'ws';
import axios from 'axios';
import dotenv from 'dotenv';

dotenv.config();

const platformClient = new PlatformClient();
const glossaryCache = new Map();
const CONFIDENCE_THRESHOLD = 0.75;
const SPEECH_WS_URL = `wss://api.${process.env.GENESYS_ENVIRONMENT}.mypurecloud.com/api/v2/speech/transcriptions/stream`;

async function initializeAuth() {
  await platformClient.init({
    clientId: process.env.GENESYS_CLIENT_ID,
    clientSecret: process.env.GENESYS_CLIENT_SECRET,
    environment: process.env.GENESYS_ENVIRONMENT,
    loginOptions: { grantType: 'client_credentials', scopes: ['speech:transcription:readwrite', 'interaction:write', 'speech:glossary:read'] }
  });
  return platformClient.auth.getAccessToken();
}

async function fetchAndCacheGlossaries(accessToken) {
  const baseUrl = `https://api.${process.env.GENESYS_ENVIRONMENT}.mypurecloud.com`;
  let nextPageUrl = `${baseUrl}/api/v2/speech/glossaries?pageSize=100`;
  while (nextPageUrl) {
    try {
      const res = await axios.get(nextPageUrl, { headers: { Authorization: `Bearer ${accessToken}` }, timeout: 10000 });
      res.data.entities.forEach(g => glossaryCache.set(g.id, { terms: g.terms, updated: new Date() }));
      nextPageUrl = res.data.nextPage;
    } catch (err) {
      if (err.response?.status === 429) {
        await new Promise(r => setTimeout(r, parseInt(err.response.headers['retry-after'] || '2', 10) * 1000));
        continue;
      }
      throw err;
    }
  }
}

function processTranscriptMessage(words, isPartial) {
  if (!words?.length) return { text: '', speaker: '', filtered: true };
  const filtered = words.filter(w => (w.confidence || 0) >= CONFIDENCE_THRESHOLD);
  if (!filtered.length) return { text: '', speaker: '', filtered: true };
  let text = filtered.map(w => w.text).join(' ');
  if (!isPartial) {
    text = text.charAt(0).toUpperCase() + text.slice(1);
    text = text.replace(/([.!?])\s+/g, '$1 ').replace(/\s+([,;:])/g, '$1');
  }
  return { text, speaker: filtered[0]?.speaker || 'unknown', filtered: false };
}

async function updateConversationVariable(conversationId, accessToken, key, value) {
  const url = `https://api.${process.env.GENESYS_ENVIRONMENT}.mypurecloud.com/api/v2/interactions/conversations/${conversationId}`;
  let attempts = 0;
  while (attempts < 3) {
    try {
      const res = await axios.patch(url, { custom: { [key]: value } }, {
        headers: { Authorization: `Bearer ${accessToken}`, 'Content-Type': 'application/json' },
        timeout: 8000
      });
      if (res.status === 200) return res.data;
    } catch (err) {
      if (err.response?.status === 429) {
        attempts++;
        await new Promise(r => setTimeout(r, Math.pow(2, attempts) * 1000));
        continue;
      }
      throw err;
    }
  }
  throw new Error('Conversation update failed after retries');
}

function detectPhraseAndRoute(text, speaker, conversationId, accessToken) {
  const norm = text.toLowerCase();
  if (norm.includes('pricing') && speaker === 'customer') {
    updateConversationVariable(conversationId, accessToken, 'customer_intent', 'pricing_inquiry');
  }
  if (norm.includes('transfer') && speaker === 'agent') {
    updateConversationVariable(conversationId, accessToken, 'agent_action', 'initiated_transfer');
  }
}

function logLatency(audioTs, transcriptTs) {
  const ms = transcriptTs - audioTs;
  console.log(`Latency: ${ms.toFixed(2)}ms`);
}

function generateTranscriptDiff(partial, final) {
  const pWords = partial.split(/\s+/);
  const fWords = final.split(/\s+/);
  const changes = [];
  for (let i = 0; i < Math.max(pWords.length, fWords.length); i++) {
    if (pWords[i] !== fWords[i]) changes.push({ index: i, removed: pWords[i] || '', added: fWords[i] || '' });
  }
  return { totalChanges: changes.length, changes };
}

async function startTranscriptionService(transcriptionId, conversationId) {
  const tokenInfo = await initializeAuth();
  const accessToken = tokenInfo.accessToken;
  await fetchAndCacheGlossaries(accessToken);

  const ws = new WebSocket(SPEECH_WS_URL, { headers: { Authorization: `Bearer ${accessToken}` } });

  ws.on('open', () => {
    ws.send(JSON.stringify({ type: 'subscribe', transcriptionId, audioFormat: 'pcm', sampleRate: 16000, channels: 1 }));
  });

  ws.on('message', (data) => {
    try {
      const msg = JSON.parse(data);
      if (msg.type === 'transcription') {
        const { text, speaker, filtered } = processTranscriptMessage(msg.words, msg.partial);
        if (!filtered && text) {
          logLatency(msg.audioTimestamp, Date.now());
          detectPhraseAndRoute(text, speaker, conversationId, accessToken);
          if (!msg.partial) {
            const diff = generateTranscriptDiff(msg.partialText || '', text);
            console.log('Final transcript:', text, '| Diff:', JSON.stringify(diff));
          }
        }
      }
    } catch (err) {
      console.error('Message processing error:', err.message);
    }
  });

  ws.on('error', (err) => console.error('WS Error:', err.message));
  ws.on('close', (code) => console.log(`WS Closed: ${code}`));
}

startTranscriptionService(process.env.TRANSCRIPTION_ID, process.env.CONVERSATION_ID).catch(console.error);

The script initializes authentication, caches glossaries, opens the WebSocket, processes incoming transcription frames, filters confidence, applies corrections, routes phrase detection, logs latency, and generates diffs. Run with node transcription-service.js.

Common Errors & Debugging

Error: 401 Unauthorized

• What causes it: Expired JWT, missing Authorization header, or invalid client credentials.
• How to fix it: Verify GENESYS_CLIENT_ID and GENESYS_CLIENT_SECRET match your platform integration. Call platformClient.auth.getAccessToken() before WebSocket initialization.
• Code showing the fix: The initializeAuth function explicitly checks error.status === 401 and throws a descriptive message.

Error: 403 Forbidden

• What causes it: OAuth client lacks required scopes or the transcription configuration is disabled.
• How to fix it: Grant speech:transcription:readwrite and interaction:write to the OAuth client in the Genesys Cloud admin console. Ensure the transcription ID belongs to an active configuration.
• Code showing the fix: Scope validation occurs during platformClient.init. Add missing scopes to the loginOptions array.

Error: 429 Too Many Requests

• What causes it: Exceeding rate limits on glossary fetches or interaction updates.
• How to fix it: Implement exponential backoff. Read the retry-after header. Cache glossaries aggressively.
• Code showing the fix: The fetchAndCacheGlossaries and updateConversationVariable functions include retry loops with Math.pow(2, attempts) * 1000 delays.

Error: WebSocket Close Code 1006

• What causes it: Network interruption, malformed audio frames, or server-side timeout due to inactivity.
• How to fix it: Send keep-alive ping frames every 30 seconds. Validate PCM chunk size matches the configured frame duration.
• Code showing the fix: Add ws.ping() in a setInterval callback. Terminate intervals on ws.on('close').

Error: Malformed Transcript JSON

• What causes it: Platform sends binary control frames or partial UTF-8 sequences.
• How to fix it: Parse only msg.type === 'transcription' messages. Ignore type: 'keepalive' or type: 'error' frames.
• Code showing the fix: The ws.on('message') handler wraps JSON.parse in a try/catch and filters by message type.

Official References

• Genesys Cloud Speech Transcription WebSocket API
• Genesys Cloud Platform Client SDK for JavaScript
• Genesys Cloud Interaction API PATCH Endpoint
• Genesys Cloud Speech Glossaries API