Last Mile Redis

The text discusses how backend applications can be optimized for faster response times by utilizing caching data close to end users through geo-routing, which can shave hundreds of milliseconds off application response times. It introduces Fly.io, a platform that enables developers to deploy Docker containers globally and build Redis apps with "instant" purge capabilities. The text also explores the concept of selective replication in cache regions by allowing local caches to accept writes while still syncing changes from the primary, which can be used for global content distribution or simulating a distributed fan-out queue.