Realtime Collaboration Lessons from KanbanSync

Building realtime apps taught me that correctness and UX must move together.

What Worked Well

• Event names mapped to user intent, not only backend state.
• Optimistic updates for immediate feedback.
• Server reconciliation for eventual consistency.

Common Pitfalls

• Duplicate events causing UI jitter.
• Missing idempotency on write operations.
• Weak conflict handling in shared lists.

My Rule

If a user can trigger an action quickly multiple times, the backend path should be idempotent and the frontend should gracefully merge updates.