Retell AI (YC W24) – API for Building Voice AI Agents That Interact Like Humans
tl;dr: You can now use our API to build human-like voice AI agents with a few lines of code. We've achieved response times averaging 800ms, reaching the level of human interactions.
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 with minimal code
Human-Like Conversations: With our API, you can build a superior voice conversation experience with just a few lines of code. 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 (see our demo).
Simple Agent Creation: You can quickly build versatile agents using just a prompt. For use cases where you want full control over how to respond to users, while still enjoying our industry-leading low latency and natural conversation, you may use our Custom LLM feature.
Web and Phone Call: We support both phone calls (inbound and outbound phone calls) and web calls. Integration into your existing products requires just a few lines of code.
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.
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