Short answer: An inventory app that works with no internet stores everything on the device first, scans barcodes with the camera, and syncs changes in the background when a connection returns. The key design decision is recording stock movements as events, so offline edits from several devices merge without losing counts.
Architecture
| Layer | Choice |
|---|---|
| App | React Native or Flutter (or native) |
| Local database | SQLite / WatermelonDB / Realm |
| Scanning | On-device camera barcode/QR scanning |
| Sync | Background queue, retries, idempotent API |
| Backend | REST or GraphQL API, PostgreSQL |
Rules that make offline work
1. Local first — every action writes locally and returns instantly.
2. Events, not totals — "+5 at 10:02" instead of "stock = 42".
3. Idempotent sync — every change has an ID, so retries never duplicate.
4. Visible state — show what's pending sync.
5. Conflict policy — decided upfront, per field.
Cost
A focused offline inventory app typically starts as a bounded first slice from €9,500. We've built one for a warehouse with no Wi-Fi — read the build note and offline-first for people who work in vans. For field apps that sync in poor coverage, see our Foi Parcurs Online and vehicle tracking case studies, our mobile app development service and native vs cross-platform mobile development.
Next step
Related services: staff augmentation, mobile app development, nearshore outsourcing and all services. Case studies: CodCheck, vehicle tracking and an AI voice agent for a hospitality group.
Not sure what team you need? Try the nearshore team planner. Or see the published pricing, live work and the nearshore lean approach, or send a short brief — we reply within one working day.
Frequently asked
Can an inventory app work completely offline?
Yes. Counts, scans and edits are stored on the device and synced when a connection returns. Only sharing with other devices needs connectivity.
What happens when two people edit the same item offline?
The app needs a conflict rule — for stock counts, record each count as an event and sum or reconcile, rather than overwriting the total.
How much does an offline inventory app cost?
A focused first version — offline storage, barcode scanning and sync — typically starts as a bounded first slice from €9,500.