Mobile offline modes: when to cache, sync, and say no
How we decide offline behaviour for field apps without building a second database.
Technical deep dive
Users ask for “full offline.” What they usually need is reliable work under flaky networks — not a complete offline twin of the server.
Classify every screen
- Must work offline — critical field tasks (inspections, checklists, signatures).
- Read-only offline — reference data cached for a shift.
- Online only — payments, admin, heavy media uploads.
If everything is “must work offline,” the project scope and budget are wrong.
Sync is a product feature
Conflict rules, last-write-wins vs manual merge, and user-visible sync status need design before code. Silent background sync that fails quietly destroys trust.
Cache with intent
Cache stable reference data aggressively. Cache user drafts until confirmed upload. Avoid caching personalised lists that go stale in minutes unless you can revalidate cheaply.
Great offline UX is specific, honest, and limited — not a slogan on a roadmap slide.
