Most apps treat the network as a given. Offline-first flips that assumption: the connection is the exception, not the rule. On Klexify, that decision shaped the entire architecture.
The core idea is simple. Read and write to a local store first — IndexedDB — and treat the server as a destination you sync to when you can. The user never waits on the network to do their work.
Web Workers keep the heavy lifting off the main thread. Diffing, queuing and conflict resolution all run in the background, so the interface stays smooth even while data moves underneath it.
The hard part isn't storage — it's reconciliation. What happens when the same record changed in two places? Get your conflict strategy right early, and offline-first stops feeling risky and starts feeling like a feature.