Vapi

✓ Editorially verified

Developer platform for building, deploying, and scaling production voice AI agents

Freemium· Build (usage-based): $0.05/min platform fee, $0.005/msg SMS/chat, 10 concurrent lines free then $10/line/mo, model/STT/TTS costs passed through at cost. Scale: custom annual contract with volume pricing. Add-ons: HIPAA compliance $2,000/mo, Zero Data Retention $1,000/mo.AudioModel-agnostic: OpenAI GPT-4o, Anthropic Claude, Google Gemini, Groq, DeepSeek, Llama; STT/TTS via Deepgram, ElevenLabs, PlayHT, Cartesia, Azure

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Best for

Product and engineering teams building voice agents for phone-based support, sales, or scheduling who want control over the model stack without engineering the real-time voice pipeline themselves.

Skip if

Non-technical operators looking for a fully packaged, no-code IVR replacement, or hobbyists who need a truly free tier with predictable flat pricing.

Vapi is a voice AI orchestration platform that lets developers assemble production-grade phone and web voice agents by wiring together a speech-to-text engine, a large language model, and a text-to-speech voice, then handling the messy real-time plumbing (turn-taking, interruption handling, endpointing, function/tool calls, telephony, and observability) so teams do not have to build it themselves. Agents can be configured through a dashboard or entirely via the REST API and SDKs (Node, Python, Web, iOS, Android, Flutter, React Native), and Vapi provisions Twilio-style numbers, SIP trunks, and inbound/outbound calling out of the box. It is model-agnostic: teams can pick from OpenAI GPT-4o, Anthropic Claude, Google Gemini, Groq, DeepSeek, or Llama for the reasoning layer, mix providers like Deepgram, ElevenLabs, PlayHT, Cartesia, and Azure for STT/TTS, and bring their own API keys to control costs. Common workflows include voice-driven customer support, outbound lead qualification, appointment scheduling, order taking, receptionist replacement, and internal IVR modernization. Enterprise features include SOC 2, HIPAA and PCI compliance, SSO, RBAC, on-call SLAs, and a dedicated deployment engineer. The platform is designed for sub-500ms latency at scale and is used by teams running millions of calls per month.

Editor's take

Vapi is the most credible general-purpose voice agent platform we have tested: it stays out of your way on model choice, exposes a clean API, and quietly solves the hardest 20% of real-time voice work. Just budget carefully — the platform fee is only one line on the bill, and HIPAA is a genuine enterprise add-on rather than a checkbox.

— The AI Tool Bible editorial team

Pros

✅ Model-agnostic stack lets you swap LLM, STT, and TTS providers per assistant and bring your own API keys
✅ Handles the real-time voice plumbing (interruption detection, endpointing, barge-in, backchanneling) that is painful to build from scratch
✅ First-class REST API and SDKs across Node, Python, Web, iOS, Android, Flutter, and React Native
✅ Built-in telephony: provisions phone numbers, supports SIP trunks, and covers inbound and outbound calls
✅ Tool/function calling and 25+ prebuilt integrations (Salesforce, HubSpot, Zapier, Make, Cal.com, etc.) for real workflows
✅ Enterprise compliance path: SOC 2, HIPAA (add-on), PCI, SSO, RBAC, Zero Data Retention available
✅ Transparent per-minute platform fee with model costs passed through at cost rather than marked up opaquely

Cons

⚠️ Total cost is hard to predict because platform fee, LLM, STT, TTS, and telephony are billed separately and stack up
⚠️ HIPAA compliance and Zero Data Retention are paid add-ons ($2,000/mo and $1,000/mo) rather than included
⚠️ Latency and voice naturalness ultimately depend on the third-party providers you choose, not Vapi itself
⚠️ Build plan retains call history only 14 days and chat history 30 days, so long-term analytics require your own pipeline
⚠️ Not a no-code tool — meaningful agents still require prompt engineering, tool wiring, and webhook code
⚠️ Concurrency beyond 10 lines costs $10/line/month, which adds up for high-volume outbound campaigns

Use cases

AI phone receptionistOutbound lead qualification callsAppointment scheduling and remindersVoice-based customer supportOrder taking and reservationsIVR replacementVoice-driven surveys and market researchDebt collection and payment remindersInsurance intake callsVoice interface for internal tools