AntiBrow is an antidetect browser for people and AI agents that run many browser identities at once. Each profile gets a coherent real-device fingerprint applied inside the browser engine, with its own cookies, storage and passkeys kept on your own disk. Cloud sync is opt-in per profile. You can manage profiles from a desktop app for Windows, macOS and Linux, or drive them with the standard Playwright API from the Node and Python SDKs, so there is no proprietary page API to learn. It also runs as an MCP server, so an agent can launch a profile, navigate, click, type and take screenshots across tool calls. Each profile has a virtual authenticator that captures and replays passkeys. Unlimited local profiles are free with one concurrent browser; paid plans add concurrency, cloud-synced profiles and Live View. Dated detector runs are published as open data under CC BY 4.0.