Most developers who work with calendars eventually hit the same strange bug. Someone subscribes to your ICS feed. Everything looks fine. Then a day or two later nothing updates. Events go missing. Times drift. Outlook users swear the feed is frozen. Google polls whenever it feels like it. Apple refreshes until it doesn t.
You debug your code. You check the ICS. You regenerate the file. You wonder if you broke SEQUENCE again.
If you have ever sent calendar invites from your own backend, you have probably seen this problem:
You send an event update
The ICS file validates
Google Calendar imports it without errors
Nothing changes
No error. No warning. The update simply does not apply.
This is one of the most common issues developers face when working with ICS. The root cause is that Google interprets the specification differently from Outlook and Apple Calendar. The behaviour is not random. It is the result of several strict internal checks.
Synara is a developer-first calendar invite and event-sync service that replaces messy .ics files with fast, reliable API-driven scheduling that's built for modern apps.
ICS is 25+ years old and parsed differently across providers. Updates get ignored, duplicated, or partially applied.
Synara uses ACE, a clean JSON event format, to normalise event data. A single API call handles invites, updates, sync, and ICS fallback, so your app gets predictable behaviour everywhere.
If you ve ever tried to send calendar invites or event updates from your app, you ve probably discovered the same thing I did: ICS is really old, inconsistent, and every provider interprets it differently.
Google, Microsoft, and Apple all parse ICS with their own quirks.
