Browser telemetry is data collected from a live browser session, such as network requests, page loads, clicks, form actions, redirects, and script behavior. It shows what a browser actually did, not just what a user or agent said it would do.
In cyber security, browser telemetry is valuable because many attacks and defenses happen inside the session. Defenders use it to spot suspicious automation, credential harvesting, endpoint enumeration, and repeated probing after access fails. It can also reveal whether an AI agent is safely retrieving information or drifting into boundary testing, because the request sequence and page interactions expose its real behavior. Analysts rely on this telemetry for detection, incident investigation, and tuning controls such as rate limits, authorization checks, and bot filtering.