Vapi
by Vapi AI Inc
FreemiumDeveloper-first voice AI API platform for building, testing, and deploying AI phone agents and voice assistants.
Overview
Vapi is a developer-first platform for building voice AI agents that can make and receive phone calls. It provides APIs for speech-to-text, LLM processing, and text-to-speech in a unified pipeline with ultra-low latency. Supports custom voices, function calling, and real-time interruption handling. Used for appointment scheduling, customer support, and outbound sales.
Pricing
Pay
per-minute
- ~$0.05/minute base cost plus model and telephony charges
- Pricing varies by voice provider and LLM used
Pros & Cons
Pros
Low-latency voice pipeline feels natural
Flexible — choose your own STT, LLM, and TTS providers
Function calling for real-time actions during calls
Good documentation and SDKs
$10 free credits to start
Cons
Developer-focused — requires coding
Per-minute costs add up at scale
Voice quality depends on chosen providers
Relatively new platform, still maturing