Flow telemetry is network metadata that summarizes communications between systems, usually including source and destination endpoints, timestamps, protocol details, and the amount of data transferred. It does not capture every packet or payload, but it gives a compact record of who talked to whom, when, and how much.
In cyber security, flow telemetry matters because it creates visibility at scale. Defenders use it to build baselines, spot unusual spikes, detect new or rare connections, and identify lateral movement or data exfiltration patterns. It is also useful for finding performance bottlenecks and for feeding monitoring and automation tools. On its own, flow data rarely proves a compromise, but it often tells analysts where to investigate first and helps turn noisy traffic into actionable signals.