Retell AI

Retell AI provides a developer platform and API designed for creating AI voice agents capable of making and receiving phone calls. The platform integrates low-latency speech-to-text, LLM orchestration, and text-to-speech, supporting features such as inbound and outbound calling, function calling, knowledge-base integration, and webhooks.

The company's technology is typically used for customer support, appointment booking, lead qualification, and outbound notifications, serving as an alternative or complement to traditional call-center tooling. Retell AI is a Y Combinator-backed startup associated with the San Francisco Bay Area and utilizes a usage-based per-minute pricing model.