OpenAI

OpenAI provides the foundational AI models that power intelligent voice applications built on Vapi. The GPT model family delivers advanced language understanding and generation capabilities, enabling voice agents to comprehend complex requests and respond naturally. Whisper offers high-accuracy speech-to-text transcription across 98 languages, converting spoken input into text for processing. OpenAI's text-to-speech models generate natural-sounding audio output with multiple voice options and support for emotional expression.

The Realtime API enables direct speech-to-speech interactions over WebSocket connections, supporting low-latency conversational experiences with automatic interruption handling. Developers can leverage function calling to connect voice agents with external tools and data sources, enabling agents to take actions like booking appointments, checking order status, or retrieving account information.

OpenAI's models support use cases ranging from customer service automation to interactive voice assistants and multilingual support systems.

Vapi and OpenAI together enable developers to build production-ready voice AI applications with minimal complexity. Vapi's voice AI platform orchestrates OpenAI's models to handle the complete voice interaction pipeline: Whisper transcribes incoming speech, GPT processes and generates intelligent responses, and TTS converts text back to natural speech. For applications requiring real-time responsiveness, Vapi can integrate with OpenAI's Realtime API to deliver sub-second latency in voice conversations. This combination supports sophisticated voice agents that understand context, maintain conversation state, and execute multi-step tasks through function calling.

Organizations use Vapi with OpenAI to deploy voice agents for customer support, appointment scheduling, order management, and interactive information systems. The integration handles infrastructure concerns like scaling, failover, and telephony connectivity, allowing teams to focus on designing effective voice experiences powered by OpenAI's language and audio capabilities.