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

# Router

The **SPQR Router** routes queries to shards and provides the interface for clients to a sharded cluster. Applications should never communicate directly with shards, but rather use the Router to route their queries.

The **Router** caches metadata from the Coordinator and guesses which shard a transaction should be routed to.

A **Router** is stateless, meaning it has no persistent state, and is typically run on dedicated resources. Or can be run anywhere else, including on the same host as the application.