What looked simple but wasn't

Multi-role permissions. Admin, teacher, parent, student, accountant — each needs a different slice of the same data, and getting the role-based access right (without duplicating logic across four dashboards) took longer than any single feature module.

Fee management edge cases. Partial payments, sibling discounts, late fee calculation, refunds for withdrawn students — the "happy path" fee flow is easy; the edge cases are where the actual engineering time went.

Attendance sync reliability. Biometric/RFID devices at the gate need to sync attendance data back to the central system in near real-time, and handling devices going offline (spotty campus wifi is more common than you'd think) without losing records took more care than expected.

Notifications that don't feel spammy. Parents want to know about attendance, fees due, and exam results — but if every module fires its own notification independently, you end up flooding parents with pings. Needed a consolidated notification queue with basic de-duping logic.

What we'd scope differently next time

If I were starting a school management app development project again, I'd push harder in the discovery phase to nail down:

Whether the school needs multi-campus support from day one (retrofitting this later is painful)
Which third-party integrations are actually required (payment gateway, SMS provider, biometric hardware) vs. "nice to have"
Whether parents/teachers will actually use a mobile app, or whether a well-designed mobile web experience covers 80% of the need for a fraction of the cost

Curious if others who've built in this space hit the same friction points, or if there's a module I'm missing that tends to blow up scope unexpectedly.