How to Build Production-Ready Voice Agents

Voice agents are transforming customer interactions, but most implementations fail at scale. Here's how to build systems that actually work in production.

The Challenge

Building a voice agent that works in a demo is easy. Building one that handles 10,000 concurrent calls with sub-300ms latency is hard.

What breaks at scale:

• Latency spikes during peak hours
• Memory leaks in long conversations
• Context loss across interruptions
• Poor handling of edge cases

Architecture Principles

Streaming-First Design

Don't wait for complete responses. Stream everything:

// Bad: Wait for full response
const response = await model.generate(prompt);
await tts.speak(response);

// Good: Stream tokens as they arrive
for await (const token of model.stream(prompt)) {
  tts.speakChunk(token);
}

Stateless Call Handling

Store conversation state in Redis, not in memory:

interface CallState {
  conversationId: string;
  context: ConversationContext;
  utterances: Utterance[];
  sentiment: number;
}

// Store in Redis with TTL
await redis.setex(`call:${callId}`, 3600, JSON.stringify(state));

Graceful Degradation

When primary systems fail, fall back intelligently:

const providers = [openai, anthropic, localModel];

for (const provider of providers) {
  try {
    return await provider.generate(prompt);
  } catch (error) {
    console.warn(`Provider ${provider.name} failed, trying next`);
  }
}

// Final fallback to scripted responses
return getScriptedResponse(intent);

Real Numbers

From our production deployments:

• Latency: p50 180ms, p99 420ms (first token)
• Uptime: 99.97% over 6 months
• Concurrent calls: 5,000+ peak
• Cost per call: $0.08 average

What's Next

This is just the foundation. In future posts we'll cover:

• Interrupt handling and conversation repair
• Multi-language support at scale
• Custom voice cloning for brand consistency
• Integration with CRM and ticketing systems

Need help building voice infrastructure? We've deployed systems handling 50K+ calls/month. Book a call to discuss your requirements.