Vapi
By Vapi
Vapi is a developer-focused platform and API for building AI voice agents, providing the infrastructure to connect speech recognition, language models, and text-to-speech into real-time phone or web voice conversations.
Definition
Vapi is a developer-focused platform and API for building AI voice agents, providing the infrastructure to connect speech recognition, language models, and text-to-speech into real-time phone or web voice conversations.
Overview
Vapi is aimed at engineers building custom voice AI applications rather than business users configuring a pre-built agent — it provides APIs and SDKs for wiring together the components of a voice pipeline: converting a caller's speech to text, sending that text to a large language model to generate a response, converting the response back to speech, and handling the low-latency, real-time audio streaming a natural-sounding phone conversation requires. This sits below more no-code, business-facing tools like Synthflow in the stack, giving developers finer control over prompts, model choice, and call logic. Because building a responsive, low-latency voice agent from scratch requires coordinating multiple specialized services — speech-to-text, an LLM, text-to-speech, and telephony — Vapi's value proposition is abstracting that orchestration into a single API, letting developers plug in providers of their choice for each stage (such as different text-to-speech models or LLMs) rather than building the pipeline and its latency/interruption handling themselves. Vapi is used by developers and startups building products such as AI receptionists, automated outbound sales callers, and voice-based customer support agents, competing with both other developer-facing voice-AI infrastructure providers and more consumer-facing platforms like Bland AI.
Key Features
- Developer API and SDKs for building custom AI voice agents
- Orchestration of speech-to-text, LLM response generation, and text-to-speech
- Support for plugging in different LLM and voice-model providers
- Real-time, low-latency audio streaming for natural phone conversations
- Telephony integration for inbound and outbound calls
- Tools for handling interruptions and turn-taking in live voice conversations