Published .ics feeds

An .ics link is a read-only source. calsync reads it and never writes to it.

When to use one

Your school or work Microsoft tenant blocks outside apps.
You only need to see someone else's calendar on yours.
The calendar comes from a service with no sign-in route, such as a team schedule or a holiday list.

The flow is one way. Events on the feed are copied onto your writable calendars. Nothing is copied back.

Get the link

Outlook on the web: Settings, Calendar, Shared calendars, Publish a calendar. Pick the calendar and the level of detail, click Publish, and copy the ICS link.
Google Calendar: Settings, pick the calendar, Integrate calendar, then copy the Secret address in iCal format.

Anyone with the link can read the calendar. Treat it like a password. If it leaks, publish it again to get a new one.

Add it to calsync

On the calsync page, add a calendar and choose a published .ics link. With the command line, run calsync auth ics LABEL and paste the link at the prompt.

Repeating events in a feed are unpacked into individual occurrences.

Good to know

Providers refresh published feeds on their own schedule. A change can take a while to show up.
calsync only sees the level of detail you published.