# Vapi

> The API-first voice-agent platform — assemble phone and web agents from any STT/LLM/TTS mix, with telephony, squads, and tool calling handled for you.

Vapi is the buy side of voice agents: define an Assistant (prompt, model, voice, tools), attach a phone number, and you're live — the platform owns orchestration, turn-taking (vendor-claimed sub-600ms responses), interruptions, telephony, and multi-assistant Squads with context handoffs. Bring any STT/LLM/TTS providers (at cost with your own keys) plus a per-minute platform fee.

Website: https://vapi.ai

Vapi is what "just give me a working voice agent" looks like as a product: an API where an **Assistant** — prompt, model, voice, tools — plus a phone number equals a live agent, with the genuinely hard parts (turn-taking, interruptions, telephony, latency engineering) as someone else's problem.

## Highlights

- **Assistants in minutes** — dashboard or API: configure prompt/model/voice/tools, attach a number, take calls.
- **Provider freedom** — mix OpenAI, Anthropic, Google, Deepgram, ElevenLabs and more; bring your own keys and model costs pass through unmarked.
- **Conversational mechanics handled** — vendor-claimed sub-600ms responses with natural turn-taking and interruption handling.
- **Squads** — multi-assistant workflows with context-preserving handoffs.
- **Tool calling mid-call** — agents hit your APIs during conversations: lookups, bookings, tickets.
- **Telephony native** — inbound/outbound numbers, BYO carrier, plus web and mobile SDK calls.

## In an AI-assisted workflow

The five-minute path: create an Assistant in the dashboard, wire a tool to your backend, attach a number, call it. Vapi is the reference "buy" option in the [realtime voice stack decision](/guides/voice/realtime-voice-apis) — and a sane prototyping layer even for teams that later [build on LiveKit](/tools/livekit).

> [!WARNING]
> Cost-model the real number: platform fee + model costs + telephony compounds per minute, and compliance add-ons (HIPAA, ZDR) are priced for enterprises. High-volume economics eventually argue for the build side — that's the trade, not a flaw.

## Good to know

Proprietary platform; SDKs on GitHub. Momentum is real: a **$50M Series B led by Peak XV** (May 2026, with M12 and Kleiner Perkins; ~$500M valuation per TechCrunch), company-stated 1M+ developers and a billion-plus calls — with TechCrunch reporting Amazon Ring routes all inbound calls through it. The full build-vs-buy map, including [Pipecat](/tools/pipecat)'s OSS pipeline and [Cartesia Line](/tools/cartesia): [Realtime Voice Agents](/guides/voice/realtime-voice-apis).

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_Source: https://agentscamp.com/tools/vapi — Tool on AgentsCamp._