Daytona provides isolated computers for AI agents so they can write and run code, install packages, call tools, browse, and keep state on a machine of their own. Buyers include model labs, companies that produce training and evaluation data, and product teams putting agents into production. The company raised a $60 million Series B at a $1 billion valuation, led again by FirstMark, which also led the $24 million Series A. Total funding is now $91 million. Daytona is using the round to build that runtime at the volume long-running agents now require, after agent-specific infrastructure moved into mainstream use this year. Those computers have to start in milliseconds, pause with state intact, fork into parallel copies, and shut down when the job ends. Daytona says it is the only provider with Linux, Windows, macOS, and GPU sandboxes on one platform, so an agent can drive a Windows desktop, test a native Mac app, optimize a CUDA kernel, or work in CAD software from the same system. The company reports revenue up about 25 times since January, with average month-over-month net revenue retention of about 135 percent. Customers named in the announcement include Meta, Cohere, Writer, Clay, n8n, Postman, Mintlify, bolt.new, Handshake, Snorkel, Surge AI, Turing, AfterQuery, and Trajectory. Writer had passed 20,000 sandboxes a day on its own stack and then provisioned 300,000 in a single month on Daytona. AfterQuery replaced an in-house Google Kubernetes cluster in a day. CEO Ivan Burazin co-founded Daytona in 2023 with CTO Vedran Jukić and chief architect Goran Draganić. Burazin and Jukić earlier built Codeanywhere, a browser-based development environment, and Burazin founded the Shift conference before serving as chief developer experience officer at Infobip. The product started as infrastructure for human developers and shifted to agent runtimes once customers began requesting environments with no person at the keyboard. The company is a 35-person team hiring in San Francisco. New angels include Patrick Collison, Tobi Lütke, Aravind Srinivas, Eric Yuan, Olivier Pomel, Adam D'Angelo, and Brendan Foody, with Qualcomm Ventures, Samsung Next, and Okta Ventures joining as strategic investors.