# Stream Lag

> Source: https://sukruyusufkaya.com/en/glossary/stream-lag
> Updated: 2026-05-13T20:56:45.200Z
> Type: glossary
> Category: veri-muhendisligi-ve-ai-altyapisi
**TLDR:** A core stream-health metric that expresses the delay gap between produced events and consumed events.

<p>Stream lag is one of the core indicators of whether real-time behavior is actually being preserved in a streaming system. As consumers fall behind the stream, decision quality and freshness can degrade. This metric may indicate insufficient capacity, partition imbalance, or consumer-side failures. Healthy stream infrastructures must monitor lag continuously.</p>