Vapi

Build Low-Latency Voice AI Agents with Full Model Control

Vapi screenshot

Build Low-Latency Voice AI Agents with Full Model Control

Vapi is an API-first platform for building, testing, and deploying voice AI agents at enterprise scale. It handles the hard real-time infrastructure — speech-to-text, LLM orchestration, text-to-speech, and telephony — so developers can ship production phone agents in minutes instead of months.

Used by Amazon Ring, Intuit, ServiceTitan, and New York Life, Vapi powers customer support, lead qualification, and appointment-scheduling agents with sub-600ms response times and natural turn-taking. Its provider-agnostic design lets teams pick from dozens of STT, LLM, and TTS providers — OpenAI, Anthropic, Google, Deepgram, ElevenLabs, Gladia, and more — or bring their own API keys to control cost and model choice, while built-in guardrails, monitoring, and SOC 2 / HIPAA / PCI compliance make it viable for regulated industries.

Pricing

    • Build: Usage-based — $0.05/min platform fee, model provider costs at cost ($0 if you bring your own API keys), $10 per concurrent line/month, community and email support
    • Chat / SMS: $0.005 per message
    • Scale (Enterprise): Fixed platform fee + committed volume, volume-based per-minute pricing, custom SLA, dedicated account team, SSO/RBAC
    • Add-ons: HIPAA compliance $2,000/month, Zero Data Retention $1,000/month

There is no flat monthly subscription on the Build plan — you pay only for what you use, with model costs passed through at cost.

Tool Summary

Value Rating (5/5)
Price Tier Paid
Cost $$$ (3/5)
Category AI Developer Tools & Automation

Features

  • Assistants: Build a voice agent from a single system prompt plus tools and structured outputs — ideal for support, booking, and qualification.
  • Squads (Multi-Assistant Orchestration): Compose multiple specialized assistants with context-preserving transfers for complex, multi-step call flows.
  • Provider-Agnostic Stack: Choose from dozens of STT, LLM, and TTS providers (OpenAI, Anthropic, Google, Deepgram, ElevenLabs, Gladia, and more) or bring your own keys to pay model costs at cost.
  • Sub-600ms Response Times: Real-time voice pipeline with natural turn-taking, engineered for enterprise call volumes.
  • Phone & Web Integration: Make and receive calls on any phone number, or embed voice calls directly inside web and mobile apps via SDKs.
  • Tool / Function Calling: Connect assistants to your APIs, databases, and existing systems so they can take real actions during a call.
  • MCP Integration: Assistants dynamically pull tools from any Model Context Protocol server during calls; Vapi also ships its own MCP server to manage assistants, numbers, and calls from MCP clients like Claude Desktop.
  • Multilingual Agents: Support for English, Spanish, French, Italian, and other languages out of the box.
  • Real-Time Monitoring: Live call analytics, transcripts, and issue surfacing for continuous agent improvement.
  • AI Guardrails: Built-in safeguards against hallucination and data-integrity issues for production reliability.
  • Enterprise Security: SOC 2, HIPAA, and PCI certification with SSO and granular RBAC.
  • Comprehensive SDKs & API: Web, server, and mobile SDKs with full documentation at docs.vapi.ai for deep custom integration.

Common Use Cases

  • Customer Support Automation: Deploy voice agents that resolve common inbound calls 24/7 and escalate complex issues to human reps with full context.
  • Outbound Lead Qualification: Run automated discovery and qualification calls, then route warm leads into the CRM with call summaries attached.
  • Appointment Scheduling: Let callers book, reschedule, and confirm appointments by phone with calendar and system integrations.
  • Insurance & Financial Services: Build compliant voice agents for policy questions and intake using HIPAA/PCI controls and zero data retention.
  • Marketplaces & Staffing Platforms: Automate two-sided phone verification, onboarding calls, and follow-ups at scale.
  • Developers & AI Agencies: Use Vapi as the voice infrastructure layer to ship client-facing phone agents without building real-time audio plumbing.

Pros ✅

  • API-first platform with full SDKs and docs.vapi.ai for deep customization
  • Provider-agnostic — pick from dozens of STT/LLM/TTS providers or bring your own keys to control cost
  • Sub-600ms response times with natural turn-taking, proven at enterprise volume (Amazon Ring, Intuit, ServiceTitan)
  • Native Model Context Protocol (MCP) support — use MCP server tools in calls, plus a Vapi MCP server to manage assistants from MCP clients
  • Squads orchestration for multi-assistant workflows with context-preserving transfers
  • SOC 2, HIPAA, and PCI compliance with SSO and RBAC for regulated industries
  • Transparent usage-based pricing with model costs passed through at cost

Cons ❌

  • Developer-focused — not a no-code builder, requires engineering to deploy well
  • Usage-based pricing can be hard to forecast for high call volumes
  • Compliance add-ons are expensive (HIPAA $2,000/mo, Zero Data Retention $1,000/mo)
  • Short default data retention on Build (14-day call history) without a paid Scale plan
  • Per-line concurrency fees add up for businesses running many simultaneous calls
  • Quality depends on the third-party STT/LLM/TTS providers you wire together