Most apps quietly assume the network is always there. Then a real user walks into a basement, a half-built apartment tower, or an elevator — and the app falls apart.

For a real-estate sales agent, that moment isn't a glitch. It's a lost lead, and a lost commission.

When we built the AM Live CRM at Aqarmap (Egypt's largest property platform), our field agents were managing 100,000+ leads a month — and a huge chunk of their day happened exactly in those dead zones: new developments, underground parking, remote plots with one bar of signal.

A "cache the last response" approach wasn't enough. We needed the app to be fully usable with zero connectivity — create a lead, move it through the pipeline, log a call — and have all of it sync cleanly the moment the network came back.

Here's the architecture we landed on, and the mistakes worth avoiding.

The core idea: the local database is the source of truth

The biggest mental shift in offline-first is this: the UI never talks to the network directly.…