Retell AI offers an API for building human-like conversational voice AI. With their hosted models and various optimizations in each step, users can experience state-of-the-art voice interaction with live demos such as receiving a phone call at a dental office or trying it on webcall with a phone number, name, and email. The API is built by developers for developers to easily integrate into products through three steps: plugging in custom LLM, creating a voice agent for different scenarios, and integrating the voice experience to phones/websites through WebSockets. Retell's conversational flow feels natural thanks to ultra-realistic voices that handle interruptions seamlessly with approximately one-second latency ensuring smooth transitions between speakers.