Mobile Offline Sync Engine & Architecture

Unreliable or fluctuating internet connectivity is a common challenge in educational institutions. YeneSchool is engineered with an offline-first philosophy: the mobile application never blocks user productivity when internet connectivity drops.

1. What Operates Completely Offline on Mobile

The mobile app caches the latest school state on device storage:

• Full Student Rosters & Photos: Browse class lists and student profiles without an active connection.
• Attendance Roll-Call: Take daily, period, and bus attendance offline.
• Continuous Assessment & Grade Entry: Enter exam, quiz, and test scores.
• Offline Timetable & Class Schedules: View room assignments and period times.
• Discipline Incident Logging: Record student behavioral notes on the spot.

2. The Local SQLite Sync Queue

When an action is taken while offline:

1. The app serializes the payload (e.g., attendance_records_batch) with a local unique UUID, monotonic timestamp, and cryptographic hash.
2. The payload is written to the device's local SQLite Database.
3. A subtle Amber cloud indicator in the top navbar indicates: "3 unsynced actions stored locally".
4. The user continues working with zero latency or spinner blocking.

3. Background Sync & Conflict Resolution Strategies

The moment network connectivity is re-established (via Wi-Fi or cellular data):

1. Network Listener Trigger: The app detects the online state change.
2. Sequential Batch Flush: The sync worker iterates through the SQLite queue in strict chronological order and posts requests to the backend sync endpoint (POST /sync/batch).
3. Conflict Resolution Strategy:
   • Last-Write-Wins with Entity Timestamps: For grade score edits, the most recent verified timestamp prevails.
   • Server Merge for Attendance: If attendance was marked on both mobile and web while split-brain, records are merged per student record.
4. Queue Pruning: Successfully committed transactions are pruned from local storage to keep the device storage footprint minimal (< 25 MB).
5. The navbar cloud icon turns green with a checkmark: "All Changes Synced".

Next Steps

• Platform Offline Mode (PWA) — Explore how desktop web offline mode operates
• Mobile App Overview — General mobile app architecture and setup
• Data Quality & Audits — Audit synced data integrity