Production-Ready Voice Agents: Monitoring Infrastructure Requirements
Real-Time Dashboards
Latency distribution: Live P50/P95/P99 latency charts Active conversations: Current concurrent call volume Error rates: STT failures, LLM timeouts, TTS errors Cost tracker: Real-time spending by provider component Geographic distribution: Call origin heatmap
Vapi dashboard provides: All above metrics without custom implementation
Automated Alerting
Latency degradation: Alert when P95 increases >20% over 5-minute window Error rate spike: Alert when error rate >5% for any component Cost overrun: Alert when spending exceeds daily budget Capacity threshold: Alert when approaching concurrent call limits Provider outage: Alert when primary provider unavailable
Alert routing: PagerDuty, Slack, email, SMS based on severity
Logging and Replay
Conversation logging: Full transcripts with timestamps Audio recording: Optional call recording (with consent) Metadata capture: Latency per component, cost per call, provider used Replay capability: Reproduce exact conversation flow for debugging
Retention: 30-90 days for troubleshooting, indefinite for compliance
Performance Trending
Week-over-week comparison: Latency, accuracy, cost trends Provider performance: Compare Deepgram vs Whisper accuracy over time Prompt A/B test results: Statistical significance of variations Seasonal patterns: Identify usage spikes and prepare capacity
A/B Testing for Optimization
What to Test
Prompt variations:
- Longer detailed prompts vs shorter focused prompts
- Different personality tones (friendly vs professional vs casual)
- Explicit instruction phrasing changes
- Context amount (full history vs recent turns only)
Voice selection:
- Male vs female voices
- Different emotional tones (warm vs neutral vs energetic)
- Voice speed and pitch variations
- Regional accent matching
Provider combinations:
- Deepgram vs Whisper for STT
- GPT-4 vs GPT-3.5 vs Claude for LLM
- ElevenLabs vs PlayHT for TTS
Workflow configurations:
- Different confirmation steps (more vs fewer)
- Clarification timing (immediate vs delayed)
- Fallback strategies (retry vs transfer vs alternative path)
Test Design
Traffic splitting: Route 50% to variation A, 50% to variation B Minimum sample size: 100+ conversations per variation for statistical significance Duration: Run for 1-2 weeks to account for day-of-week variability Randomization: Ensure equal distribution across time periods and user demographics
Success Metrics
Primary: Conversation completion rate, task success rate Secondary: Average latency, cost per conversation, user satisfaction Statistical significance: p < 0.05 for declaring winner Practical significance: >5% improvement to justify change complexity
Vapi A/B Testing
Dashboard configuration: Create multiple agent variants Traffic routing: Percentage-based automatic routing Real-time results: Live comparison of key metrics Easy rollback: Revert to baseline if performance degrades
Scalability Requirements
Concurrent Call Capacity
Development: 10-50 concurrent calls for testing Small production: 100-500 concurrent calls Medium production: 1,000-10,000 concurrent calls Large production: 10,000+ concurrent calls Enterprise scale: 100,000+ concurrent calls
Vapi capability: Scales from 1 to millions of concurrent calls without configuration changes
Geographic Distribution
Single region: Latency acceptable for local user base Multi-region: US East, US West, EU, APAC regions for global deployment Benefits: Reduced latency through proximity, compliance with data residency
Implementation: Vapi automatically routes to nearest region
Provider Failover
Primary provider outage: Automatic switch to backup provider Example chain: Deepgram → AssemblyAI → Whisper User experience: Seamless, no conversation interruption Recovery: Automatic return to primary when available
Vapi orchestration: Built-in failover without manual configuration
Load Balancing
Traffic distribution: Spread load across provider API endpoints Rate limiting: Respect provider rate limits, queue overflow Circuit breaking: Temporarily disable failing providers Health checks: Continuous provider availability monitoring