Retell uses OpenAI models to help power 100M monthly calls

Retell, a voice agent platform, leverages OpenAI models including GPT-6 Astra and Codex to handle 100 million monthly calls. GPT-6 Astra ranks at the top of Retell's voice agent benchmark, while Codex contributes to the company's high revenue efficiency of $1.6M annual run rate per employee. The case highlights OpenAI's impact on scaling real-world voice AI applications.