Over the last months, I’ve been working on solving a problem that kept appearing in many companies I cooperated with:
calendar chaos across multiple platforms.
Google Calendar, Outlook, iCloud, internal CRMs, booking systems, sales tools — everything works well individually, but once companies start using multiple systems, conflicts, double bookings and missed meetings become surprisingly common.
Main problems we observed:
- double bookings between Google & Outlook
- no real-time synchronization
- lack of central control
- fragile webhook-based integrations
- poor scalability for larger teams
What worked well:
Instead of building fragile one-way syncs, we focused on:
- real-time bidirectional synchronization
- conflict detection before events are created
- centralized event processing layer
- unified API for all calendar providers
Key lessons learned:
- Polling-based sync is unreliable at scale
- Webhooks alone are not enough
- Event normalization is harder than expected
- Timezone handling is one of the biggest hidden problems
- Race conditions appear much more often than people expect
Technical stack:
- REST API based integration layer
- message queue for event processing
- conflict resolution logic
- audit logging for every sync operation
Questions to the community:
- How do you currently handle multi-calendar synchronization?
- Have you experienced issues with calendar conflicts in production?
- What platform gave you the biggest headaches?
Happy to exchange experiences — this area seems simple on the surface but quickly becomes complex in real production systems.
