# Vapi — The developer platform for voice AI agents, bring your own model, voice and telephony, and Vapi orchestrates the call.

> Source: The Agents Index — https://theagentsindex.com/vapi (structured, researched, re-verified)
> Facts last verified: 2026-07-23

Vapi is a developer-first platform for building, testing and deploying voice AI agents that make and answer phone calls. It is API-first and model-agnostic: you assemble an agent from your choice of speech-to-text, language model and text-to-speech provider, and Vapi orchestrates the real-time pipeline — turn-taking, interruptions, telephony and function calls — at sub-500ms latency. It is one of the most widely adopted voice-agent stacks among technical teams building custom phone automation. Founded in 2023 by University of Waterloo classmates Jordan Dearsley (CEO) and Nikhil Gupta (CTO), who had previously built Superpowered, a Y Combinator-backed calendar app, Vapi launched publicly in 2024 and has raised $72M total — a $20M Series A led by Bessemer Venture Partners (December 2024) and a $50M Series B led by Peak XV Partners (May 2026, a reported ~$500M valuation per TechCrunch; the round’s own announcement did not disclose a figure).

| Fact | Value |
| --- | --- |
| Website | https://vapi.ai |
| API | Yes |
| Best for | Engineering teams that want maximum control to build custom voice agents on their own choice of model, voice and telephony. |
| Not for | Non-technical teams who want a turnkey, no-code voice agent live in an afternoon. |

## Verdict

Vapi is the builder’s choice for voice AI: an API-first, model-agnostic platform that hands developers control over every layer — transcription, model, voice and telephony — with real-time orchestration and sub-500ms latency. Its bring-your-own-provider design means you can chase the best model or cheapest voice without rebuilding the agent, and enterprise features (HIPAA, zero-data-retention, SLAs) let it scale to millions of calls. The honest catch is cost transparency: the $0.05/min headline is only the orchestration fee, and the true all-in rate is usually several times that once you add a model, a good voice and telephony. Pick Vapi if you have engineers who want to build a bespoke voice agent and own the stack; skip it if you want a no-code tool that hides the plumbing.

## Strengths and weaknesses

- ✓ Gives developers a clean, well-documented API and control over every layer of a voice agent — a top-tier builder’s platform.
- ✓ Model- and voice-agnostic (bring your own STT/LLM/TTS), so you are never locked into one provider’s quality or price.
- ✓ Proven at genuine enterprise scale, not just funding hype: Amazon Ring evaluated 40+ AI voice vendors before choosing Vapi and now routes 100% of its inbound call volume through the platform, and Vapi has processed over 1 billion calls for 1M+ developers.
- ✗ The advertised $0.05/min is only the orchestration fee — real all-in cost typically lands around $0.13–$0.33/min once model, voice and telephony are added.
- ✗ Developer-first: it rewards engineering ownership and is not a turnkey no-code tool for non-technical teams.
- ✗ Compliance is metered separately even on the Scale plan — HIPAA costs an additional $2,000/month and Zero Data Retention $1,000/month, on top of the per-minute rate and contract.
- ⚠ True per-minute cost is the sum of several passed-through services, so the headline platform fee understates spend.
- ⚠ It is a programmable platform, not a no-code builder — expect to write code and own the configuration.

## Key features

- **Bring-your-own pipeline** — Pick your own STT, LLM and TTS providers; Vapi is model-agnostic rather than locking you to one vendor.
- **Real-time orchestration** — Handles turn-taking, interruptions and telephony at sub-500ms average latency so calls feel natural.
- **Tool / function calling** — Agents call external functions and webhooks mid-call to fetch data, book appointments or trigger workflows.
- **Squads (multi-agent)** — Coordinate multiple specialised agents that hand off to one another within a single call.

## Use cases

- **Inbound call deflection** — A support line answers common questions and completes routine tasks autonomously, escalating to a human only when needed.
- **Outbound automation** — Appointment reminders and lead-qualification calls run at volume, with the agent updating your systems via function calls.

## Integrations

Model providers — OpenAI, Anthropic, Google · Speech providers — bring your own STT & TTS · Telephony — Twilio, Vonage or imported SIP numbers · Custom tools via function calling & MCP

## Sources

- https://vapi.ai/pricing
- https://www.lindy.ai/blog/vapi-ai
- https://www.globenewswire.com/news-release/2026/05/12/3292882/0/en/vapi-raises-50m-series-b-as-it-reaches-1-billion-calls-powering-the-next-generation-of-enterprise-voice-ai.html
- https://www.globenewswire.com/news-release/2024/12/12/2996317/0/en/Vapi-Dials-in-20M-in-Series-A-Led-by-Bessemer-to-Bring-AI-Voice-Agents-to-Enterprise.html
- https://techcrunch.com/2026/05/12/vapi-hits-500m-valuation-as-amazon-ring-chose-its-ai-platform-over-40-rivals/