calcom/cal.com

Expected Results

• Any valid iCalendar feed URL should be accepted regardless of URL suffix

• Validation should be based on:

  • valid URL format
  • successful HTTP response
  • Content-Type: text/calendar
  • optionally presence of BEGIN:VCALENDAR

Technical details

• Validation logic:

  @Matches(/\.ics$/)
  

• Example valid feed:

  https://caldav.soverin.net/calendars/MyCalendar-REDACTED?export
  

• Response headers:

  Content-Type: text/calendar
  

• Node.js version:

  N/A (using cal.com hosted version)
  

• Browser:

  Firefox, and also tried through the cal.com API
  

Evidence

Tested by:

• Opening the ICS feed URL directly in the browser
• Verifying the endpoint returns a valid iCalendar payload
• Verifying the response Content-Type is text/calendar
• Verifying the same feed works in other calendar clients/services
• Attempting to add the feed in Cal.com and observing rejection due to .ics suffix validation

The cal.com UI wasn't very helpful as it only showed a very basic message:

I also ran the curl command which showed explicitly that the missing .ics suffix was the culprit:

% curl --request POST \
  --url https://api.cal.com/v2/calendars/ics-feed/save \
  --header 'Authorization: REDACTED' \
  --header 'Content-Type: application/json' \
  --data '
{
  "urls": [
    "https://REDACTED:[email protected]/calendars/MyCalendar-REDACTED?export"
  ],
  "readOnly": true
}
'
{"status":"error","timestamp":"2026-05-07T20:01:29.624Z","path":"/v2/calendars/ics-feed/save","error":{"code":"BadRequestException","message":"Bad Request Exception","details":{"errors":[{"target":{"readOnly":true,"urls":["https://REDACTED:[email protected]/calendars/MyCalendar-REDACTED?export"]},"value":["REDACTED:[email protected]/calendars/MyCalendar-REDACTED?export"],"property":"urls","children":[],"constraints":{"IsICSUrlConstraint":"The URL must be a valid ICS URL (ending with .ics) pointing to a public host"}}]}}}%