What is Vapi?
Vapi is a voice agents platform that lets developers build, test, and deploy custom AI-powered voice assistants at scale. It handles the underlying voice infrastructure so teams can focus on designing the actual call experience. The platform supports inbound and outbound call workflows and fits use cases like customer support, appointment booking, sales calls, prior authorization, and product onboarding. Pre-built templates, a full API, and SDKs let teams get a voice agent live in days. Vapi also supports SMS and chat channels alongside voice.
Features & Benefits
- Ultra-Low Latency: Deliver voice agent responses in under 500ms for real-time, natural-sounding conversation.
- Natural Conversation: Manage turn-taking, human-like voices, custom pronunciation, and custom transcription keywords to produce human-like voice agent interactions.
- Multilingual Support: Build voice agents that converse in English, Spanish, Mandarin, or over 100 other supported languages.
- Custom Model Support: Bring your own transcription, LLM, or text-to-speech models, including self-hosted models, or choose from 200+ built-in model integrations.
- Tool Calling and Live Data Access: Connect your APIs as tools so voice agents can fetch external data and trigger actions, including MCP, during a live call.
- Automated Testing: Design test suites using simulated voice agents to catch hallucination risks before deploying to production.
- A/B Experimentation: Test variations of prompts, voices, and call flows to find what performs best in production.
- Telephony Control: Configure custom SIP support, warm call transfers, voicemail detection, and DTMF support for full telephony flexibility.
- Pre-Built Templates: Start from one of thousands of pre-made templates or build a call flow from scratch.
- Observability: Monitor live call performance and connect to your existing observability stack to catch issues in production.
- AI Guardrails: Apply built-in conversation guardrails to prevent model hallucinations and maintain data integrity across calls.
- Integrations: Connect with 40+ third-party apps and services across telephony, CRM, storage, automation, and communication platforms.
- API-Native Configuration: Access every platform capability via API with thousands of configuration options for complete developer control.
Real-World Applications
A logistics company handling hundreds of daily inbound calls can deploy voice agents to qualify loads, fetch available jobs from internal systems, and route shippers without a human on the line. Vapi’s tool-calling capability lets the agent pull live broker data mid-call. The same voice agents platform scales up or down to meet call volume spikes without manual intervention.
Healthcare organizations may use voice agents to handle prior authorization workflows and patient onboarding. The platform’s HIPAA zero data retention option makes it possible to meet compliance requirements without building that infrastructure internally. Automated testing tools let clinical operations teams validate agent behavior before going live.
Sales and customer service teams can run outbound call campaigns using voice agents configured with custom prompts, specific voices, and defined conversation flows. A/B experimentation lets teams continuously test which prompt variations and voice styles produce better outcomes. Call history and observability tools make it possible to review performance and catch problems early.
Development teams building new voice-native products can use Vapi’s API-first architecture to integrate voice agents directly into a web or mobile app. Custom SIP support and warm transfer capability let engineering teams design call routing logic that fits their existing telephony setup. Teams that need multilingual voice agents can configure support for over 100 languages without switching platforms.
