Sierra is an enterprise AI company co-founded by Bret Taylor and Clay Bavor that builds autonomous AI agents specialized for customer service and support, allowing businesses to automate complex user interactions with accuracy and brand consistency. The company’s platform, Agent OS, supports both no-code and programmatic agent development, helping organizations deploy intelligent assistants tailored to their operations. In 2025, Sierra secured $350 million in funding, valuing the company at about $10 billion, and expanded its client base to include hundreds of enterprises, including brands like SoFi, Brex, and Ramp.