Turtini

See your calendar on your phone, Outlook or Google

Subscribe link (read-only): in "Sharing and settings", choose calendars and "Busy times only" or "Full details", then "Make link". The link is shown once; anyone with it can read what it shows, so treat it like a password. Revoke it at any time and it stops working immediately. Calendars you lose access to drop out of it on their own.

Two-way sync: connect the Google or Microsoft 365 account you use for an organization. Changes made in either place show in both. When the same event was changed in both places, the later change wins and the calendar shows which version was kept.

Add a calendar by address: paste a webcal:// or https:// calendar address (a school, a league, a public holiday feed). Turtini fetches it on its own servers every few hours.

Export: download your calendars as a .ics file at any time.