> ## Documentation Index
> Fetch the complete documentation index at: https://routeme.sh/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Lag checks

Lag checks verify that your node is **up to date** with the chain. A node that is far behind the tip can serve stale data, which is unacceptable for many use cases.

## **How they work (at a high level)**

* We measure how far each node lags behind the chain and apply internal thresholds. Nodes that are too far behind may be marked as having failed a lag check.
* Severe lag can lead to immediate temporary removal; minor or occasional lag may be treated more leniently. The exact rules are internal and tuned over time.
* Common causes: slow sync, overloaded nodes, or network issues between the node and the chain.

## **What you can do**

Keep your nodes well synced and healthy. Monitor your infrastructure so you don’t fall behind the tip. If you see lag check failures in [Inspect](/provider/inspect), improve sync and stability for that node.

See [When checks fail](/provider/quality-checks-recovery) for what happens after a failure and how to monitor recovery.