companies

Retell AI

YC-backed platform for building LLM voice agents that answer contact-center calls, with a visual conversation builder and per-minute usage pricing.

Retell AI came out of Y Combinator's W24 batch, founded in 2023 by Bing Wu (an ex-ByteDance/TikTok product manager), Zexia Zhang (previously on Google's speech translation team), along with Todd Li, Weijia Yu, and Evie Wang. The team is based in San Carlos, California, and built the company around a specific, unglamorous problem: most inbound calls to a corporate call center are simple, repetitive, tier-one requests that a human shouldn't need to answer. The product lets developers and BPOs build phone agents that handle exactly that tier of call — status checks, appointment confirmations, routine account questions — while escalating anything unusual to a person. It combines a drag-and-drop conversation flow builder with an underlying API, so both non-technical operators and engineering teams can ship an agent without starting from a blank prompt. Retell grew quickly off a $4.6 million seed round backed by Alt Capital, Y Combinator, and Carya Venture, reporting tens of millions in annual revenue by 2025, and was named to Wing VC's Enterprise Tech 30 list in 2026.

Founded

2023

Headquarters

San Carlos, United States

Sector

applications