Sierra, founded in 2023 by Bret Taylor and Clay Bavor, brought unusually heavyweight backgrounds to a customer service startup: Taylor previously co-founded Quip, served as Facebook's CTO, was Salesforce's co-CEO, and chairs OpenAI's board, while Bavor spent eighteen years at Google leading Google Labs, its AR/VR efforts, and Google Workspace's product and design teams.
That pedigree translated into rapid growth: Sierra's Agent OS platform, publicly launched in February 2024, reached $100 million in annual recurring revenue within seven quarters and passed $150 million by early 2026, with customers including WeightWatchers, Sonos, SiriusXM, and OluKai. Agents built on the platform handle text, voice, email, and SMS, and take real actions, processing orders, managing subscriptions, handling returns, rather than only answering questions.
There's no free tier; Sierra sells through enterprise contracts, and the company raised $950 million in May 2026 at a $15.8 billion valuation. For an enterprise consumer brand evaluating AI customer service vendors by growth trajectory and backing, Sierra's founder pedigree and rapid revenue growth since 2023 make it one of the most closely watched names in this category.
