Skip to main content Implement real-time streaming transcription with Deepgram.
Use when building live transcription, voice interfaces,
or real-time audio processing applications.
Trigger with phrases like "deepgram streaming", "real-time transcription",
"live transcription", "websocket transcription", "voice streaming".
npx skills add jeremylongshore/claude-code-plugins-plus-skills --skill deepgram-core-workflow-b ai automation claude-code devops mcp ai-agents
Deepgram Core Workflow B: Live Streaming Transcription
Overview
Real-time streaming transcription using Deepgram's WebSocket API. The SDK manages the WebSocket connection via listen.live(). Covers microphone capture, interim/final result handling, speaker diarization, UtteranceEnd detection, auto-reconnect, and building an SSE endpoint for browser clients.
Prerequisites
@deepgram/sdk installed, DEEPGRAM_API_KEY configuredAudio source: microphone (via Sox/rec), file stream, or WebSocket audio from browser
For mic capture: sox installed (apt install sox / brew install sox)
Instructions
Step 1: Basic Live Transcription
import { createClient, LiveTranscriptionEvents } from '@deepgram/sdk';
const deepgram = createClient(process.env.DEEPGRAM_API_KEY!);
const connection = deepgram.listen.live({
model: 'nova-3',
language: 'en',
smart_format: true,
punctuate: true,
interim_results: true, // Show in-progress results
utterance_end_ms: 1000, // Silence threshold for utterance end
vad_events: true, // Voice activity detection events
encoding: 'linear16', // 16-bit PCM
sample_rate: 16000, // 16 kHz
channels: 1, // Mono
});
// Connection lifecycle events
connection.on(LiveTranscriptionEvents.Open, () => {
console.log('WebSocket connected to Deepgram');
});
connection.on(LiveTranscriptionEvents.Close, () => {
console.log('WebSocket closed');
});
connection.on(LiveTranscriptionEvents.Error, (err) => {
console.error('Deepgram error:', err);
});
// Transcript events
connection.on(LiveTranscriptionEvents.Transcript, (data) => {
const transcript = data.channel.alternatives[0]?.transcript;
if (!transcript) return;
if (data.is_final) {
console.log(`[FINAL] ${transcript}`);
} else {
process.stdout.write(`\r[interim] ${transcript}`);
}
});
// UtteranceEnd — fires when speaker pauses
connection.on(LiveTranscriptionEvents.UtteranceEnd, () => {
console.log('\n--- utterance end ---');
});
Step 2: Microphone Capture with Sox import { spawn } from 'child_process';
function startMicrophone(connection: any) {
// Sox captures from default mic: 16kHz, 16-bit signed LE, mono
const mic = spawn('rec', [
'-q', // Quiet (no progress)
'-r', '16000', // Sample rate
'-e', 'signed', // Encoding
'-b', '16', // Bit depth
'-c', '1', // Mono
'-t', 'raw', // Raw PCM output
'-', // Output to stdout
]);
mic.stdout.on('data', (chunk: Buffer) => {
if (connection.getReadyState() === 1) { // WebSocket.OPEN
connection.send(chunk);
}
});
mic.on('error', (err) => {
console.error('Microphone error:', err.message);
console.log('Install sox: apt install sox / brew install sox');
});
return mic;
}
// Usage
const mic = startMicrophone(connection);
// Graceful shutdown
process.on('SIGINT', () => {
mic.kill();
connection.finish(); // Sends CloseStream message, waits for final results
setTimeout(() => process.exit(0), 2000);
});
Step 3: Live Diarization const connection = deepgram.listen.live({
model: 'nova-3',
smart_format: true,
diarize: true,
interim_results: false, // Only final for cleaner diarization
utterance_end_ms: 1500,
encoding: 'linear16',
sample_rate: 16000,
channels: 1,
});
connection.on(LiveTranscriptionEvents.Transcript, (data) => {
if (!data.is_final) return;
const words = data.channel.alternatives[0]?.words ?? [];
if (words.length === 0) return;
// Group consecutive words by speaker
let currentSpeaker = words[0].speaker;
let segment = '';
for (const word of words) {
if (word.speaker !== currentSpeaker) {
console.log(`Speaker ${currentSpeaker}: ${segment.trim()}`);
currentSpeaker = word.speaker;
segment = '';
}
segment += ` ${word.punctuated_word ?? word.word}`;
}
console.log(`Speaker ${currentSpeaker}: ${segment.trim()}`);
});
Step 4: Auto-Reconnect with Backoff class ReconnectingLiveTranscription {
private client: ReturnType<typeof createClient>;
private connection: any = null;
private reconnectAttempts = 0;
private maxReconnectAttempts = 10;
private baseDelay = 1000;
constructor(apiKey: string, private options: Record<string, any>) {
this.client = createClient(apiKey);
}
connect() {
this.connection = this.client.listen.live(this.options);
this.connection.on(LiveTranscriptionEvents.Open, () => {
console.log('Connected');
this.reconnectAttempts = 0; // Reset on success
});
this.connection.on(LiveTranscriptionEvents.Close, () => {
this.scheduleReconnect();
});
this.connection.on(LiveTranscriptionEvents.Error, (err: Error) => {
console.error('Connection error:', err.message);
this.scheduleReconnect();
});
return this.connection;
}
private scheduleReconnect() {
if (this.reconnectAttempts >= this.maxReconnectAttempts) {
console.error('Max reconnection attempts reached');
return;
}
const delay = this.baseDelay * Math.pow(2, this.reconnectAttempts)
+ Math.random() * 1000; // Jitter
this.reconnectAttempts++;
console.log(`Reconnecting in ${Math.round(delay)}ms (attempt ${this.reconnectAttempts})`);
setTimeout(() => this.connect(), delay);
}
send(chunk: Buffer) {
if (this.connection?.getReadyState() === 1) {
this.connection.send(chunk);
}
}
close() {
this.maxReconnectAttempts = 0; // Prevent reconnect
this.connection?.finish();
}
}
Step 5: SSE Endpoint for Browser Clients import express from 'express';
import { createClient, LiveTranscriptionEvents } from '@deepgram/sdk';
const app = express();
app.get('/api/transcribe/stream', (req, res) => {
res.setHeader('Content-Type', 'text/event-stream');
res.setHeader('Cache-Control', 'no-cache');
res.setHeader('Connection', 'keep-alive');
const deepgram = createClient(process.env.DEEPGRAM_API_KEY!);
const connection = deepgram.listen.live({
model: 'nova-3',
smart_format: true,
interim_results: true,
encoding: 'linear16',
sample_rate: 16000,
channels: 1,
});
connection.on(LiveTranscriptionEvents.Transcript, (data) => {
const transcript = data.channel.alternatives[0]?.transcript;
if (transcript) {
res.write(`data: ${JSON.stringify({
transcript,
is_final: data.is_final,
speech_final: data.speech_final,
})}\n\n`);
}
});
// Client provides audio via a paired WebSocket (see browser setup)
req.on('close', () => {
connection.finish();
});
});
Step 6: KeepAlive for Long Sessions // Deepgram closes idle connections after ~10s of no audio.
// Send KeepAlive messages during silence periods.
connection.on(LiveTranscriptionEvents.Open, () => {
const keepAliveInterval = setInterval(() => {
if (connection.getReadyState() === 1) {
connection.keepAlive();
}
}, 8000); // Every 8 seconds
connection.on(LiveTranscriptionEvents.Close, () => {
clearInterval(keepAliveInterval);
});
});
Output
Live WebSocket transcription with interim/final results
Microphone capture pipeline (Sox -> Deepgram)
Speaker diarization in streaming mode
Auto-reconnect with exponential backoff and jitter
SSE endpoint for browser integration
KeepAlive handling for long sessions
Error Handling Issue Cause Solution WebSocket closes immediately Invalid API key or bad encoding params Check key, verify encoding/sample_rate match audio No transcripts received Audio not being sent or wrong format Verify connection.send(chunk) is called with raw PCM High latency Network congestion Use interim_results: true for perceived speed rec command not foundSox not installed apt install sox or brew install soxConnection drops after 10s No audio + no KeepAlive Send connection.keepAlive() every 8s Garbled output Sample rate mismatch Ensure audio sample rate matches sample_rate option
Resources
Next Steps Proceed to deepgram-data-handling for transcript processing and storage patterns.
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