For the last five years, I've worked on web apps that follow the same pattern: build a backend, set up Postgres, wire up REST endpoints, fetch data on the client, cache it in React state or Redux.
Somewhere along the way, I realized a lot of the data I was sending to the server never needed to go there.
Form drafts. UI preferences. Search indexes. Cached API responses. Offline queues. All of it lives on the client already — it just takes a detour through the network for no real reason.
The latency tax
A round-trip to the server costs 200-500ms on a fast connection. On mobile, it's worse. Multiply that by every interaction that needs data, and your app feels sluggish even when the UI is technically fast.
