Retell AI

🔥 Retell AI – API for building human-like conversational voice AI

We help developers implement human-like voice agents in a day instead of months. Plug in your LLM, a voice agent in born!

Tl;dr: You can now use our API to build human-like voice AI agents with your LLM. We've achieved response times averaging 800ms, reaching the level of human interactions. (see our demo or call +1 (415) 831-7577 to try it out).

Problem — Building human-like voice AI agents is hard

  • Human-like interaction is hard: Building a voice AI agent that can talk seems easy (stitching together speech-to-text, LLM, and text-to-speech), but making it interact like humans is hard. In human conversation, one has to respond fast and handle all kinds of situations (handling interruptions, knowing when it's your turn to speak, etc).

  • Long development time: Developers building voice products spend hundreds of hours focusing on the voice conversation experience alone.

  • Quality often falls short: Current voice AI products often have long response latency (>3s), do not know when to appropriately speak (might interrupt you too much, or respond not quickly enough), and do not handle user interruptions well (AI and human talking over each other), and the list goes on.

Solution — API for building human-like voice AI agents

  • Human-Like Conversations: With our API, you can build a superior voice conversation experience with your LLM. We've achieved response times averaging 800ms, reaching the level of human interactions. We also handle interruptions and provide smart turn-taking determination to achieve seamless conversational exchanges.

  • Connect your LLM easily: Plug in your LLM and create a human-like voice agent easily.

  • WebSocket Support: Connect directly with your users through your web frontend or via phone. You won't have to manage audio bytes – we'll handle that for you.

Who is this product meant for?

Anyone building a voice experience can benefit from using Retell AI. Whether you're developing AI call agents, AI coaching apps, or AI lifelike companions, we are your trusted ally in creating the best conversational experience for your users.

How to get started?

Have questions?

Our Ask:

  • Give us a try! We provide founder's support dedicated to helping you succeed. Please don't hesitate to schedule a meeting with us anytime!

  • If you know anyone who could benefit from Retell AI, we would appreciate a warm introduction. :)

Warm regards from the five-founders' team. (From left to right: Todd, Weijia, Zexia, Bing & Evie)