Vapi (vapi.ai) is a voice AI platform built for developers who want full control over every layer of a conversational phone agent. Rather than a no-code builder, Vapi provides the orchestration infrastructure: you bring your own LLM, your own speech-to-text engine, your own TTS voice, and your own telephony provider — Vapi coordinates them all with sub-600ms latency.
How Vapi Works
You configure a voice agent via JSON or the dashboard, specifying the model (GPT-4o, Claude, Gemini, Mistral), voice provider (ElevenLabs, Deepgram, Azure), and call flow logic. Vapi handles the real-time audio streaming, interruption detection, and turn-taking. Calls can be inbound or outbound, and the platform supports SIP lines for scaling to multiple simultaneous conversations.
Key Features
- Model-agnostic — plug in any LLM, STT, or TTS provider; no vendor lock-in
- Sub-600ms response latency — natural turn-taking with minimal perceptible delay
- Inbound and outbound calling — handles customer support, lead qualification, scheduling, and more
- Webhook and API integration — full programmatic control over call routing, data extraction, and CRM updates
- Scalable concurrency — SIP lines can be added per concurrent call slot as volume grows
- Enterprise options — HIPAA compliance and SOC 2 available as add-ons
Vapi Pricing
- Free trial — $10 in free credits for new users (~150–200 minutes of testing depending on configuration).
- Usage-based — $0.05/min — platform orchestration fee per call minute. Third-party costs for STT, TTS, LLM, and telephony are billed separately by their respective providers, bringing typical all-in cost to $0.13–$0.31/min.
- Enterprise — custom pricing — unlimited concurrency, 24/7 support, HIPAA compliance, dedicated account manager, bundled third-party billing.
Who Should Use Vapi?
Vapi is the right tool for engineering teams that need deep control over voice infrastructure. If you are building a high-volume inbound support line, an outbound sales dialer, or an appointment scheduling agent, and you have developers available to manage the stack, Vapi delivers best-in-class flexibility and latency. Non-technical teams or those wanting predictable all-in-one billing should evaluate alternatives like ElevenLabs Conversational AI or Synthflow.
