Use cases
Looking for a particular job?
Trying to get Google Calendar onto an iPhone?
Importing Google calendars into iCloud is the whole of what this does for Google. The name is the job: a cal collapse is several calendars becoming one iCloud calendar you already have.
Trying to subscribe to Google Calendar on an iPhone?
Adding the Google account, or the secret iCal URL, and why neither lands in the iCloud calendar Apple Calendar already shows.
Syncing a work calendar?
Google Workspace calendars work the same way, with the read-only access and the absence of invitation emails that a shared work calendar needs.
Sitting on a pile of webcal subscriptions instead?
Copying webcal feeds into one iCloud calendar is the other half of the same job — TeamSnap, ParentSquare, or any feed that publishes one, written into a calendar you already have rather than added as yet another subscription in Apple Calendar.
Trying to import an .ics file into Apple Calendar?
Apple still does the one-shot dump; CalCollapse can upload and replace into an iCloud calendar you already have. Labels and busy blocks apply. It will not stay current until you replace the file.
Trying to get a team schedule onto an iPhone?
Sync TeamSnap with iCloud. A school calendar? Sync ParentSquare with iCloud.
Comparing this against a paid sync tool?
OneCal alternatives for Google to iCloud covers what you give up by choosing the smaller thing, as well as what you stop paying for.
Arrived here from a scheduling tool?
How this differs from Calendly — booking links and calendar sync solve different halves of the same complaint, and this is the sync half.