Understanding `notify_participants` in the Calendar and Events API

Question and Answers
2

Hello Julianna,

No, notify_participants is NOT provider-aware. It’s a simple boolean that maps directly to provider APIs:

  • Google: notify_participants=true → sendUpdates=all, false → sendUpdates=none

  • Microsoft/Outlook: Only supports true (returns 400 error if false)

When notify_participants=true:

  1. Google Calendar uses sendUpdates=all, which tells Google to “send notifications to all guests” - but Google decides how to notify them:

    • Google participants: Usually just a calendar notification (no email)

    • Non-Google emails: Email with ICS attachment

  2. Outlook/Exchange always sends email invitations to all participants (can’t be disabled via Nylas API)

You cannot update an event with different notify_participants values per participant. The API applies one value to the entire event, and you cannot make multiple calls to the same event with different notification settings for different guests - the last update would override the previous one.

Workaround

For Google Calendar specifically, rely on Google’s native behavior: when you use notify_participants=true, Google already handles same-provider participants more gracefully (calendar notifications vs emails). For cross-provider scenarios, there’s currently no way to selectively notify only non-Google participants without also notifying Google ones.