If you're building a dApp, you've probably written something like this: const cached = await redis . get ( `cdp:position: ${ user } ` ); if ( cached ) return JSON . parse ( cached ); const position = await cdpContract . methods . getPosition ( user ). call (); await redis . setEx ( `cdp:position: ${ user } ` , 60 , JSON . stringify ( position )); // 60s TTL return position ; Enter fullscreen mode Exit fullscreen mode This works, but there's a hidden problem: your data is stale for up to 60 seconds by design. And you're making RPC calls every 60 seconds regardless of whether anything actually changed on-chain. For most protocol contracts — a CDP vault, a staking contract, a price oracle, a liquidity pool — transactions are relatively rare. Most users are just reading. The contract state sits unchanged for minutes, hours, sometimes days. The insight Contract state only changes when a transaction is mined.…