Contest calendars for Google Calendar

Subscribe

Click Add to Google Calendar and confirm — that's the whole thing. No signup, and nothing to install.

The button opens Google Calendar in a new tab and asks you to confirm — you'll need to be signed in, and it has to be a browser, not the mobile app. Prefer to do it by hand, or using Apple Calendar or Outlook? Copy the value instead: the two CodeChef entries are feed URLs, for Other calendars → + → From URL; the Codeforces and LeetCode ones are calendar IDs, for Subscribe to calendar.

Why your CodeChef calendar stopped updating

It probably didn't break. The feed you subscribed to was almost certainly abandoned years ago, and a dead calendar feed looks exactly like a working one with no upcoming contests. Nothing errors. It just quietly stops.

I checked every public CodeChef calendar I could find. All of them are dead, including CodeChef's own:

Measured on 4 September 2026 by fetching each calendar's public .ics. The same check runs hourly in CI — if a feed recommended above goes stale, the build fails and I get an email.

The fix isn't to find a better feed. There isn't one. It's to generate the data from CodeChef's own contests API, which is public, unauthenticated and perfectly healthy. That's all this project does.

How to subscribe

Google Calendar

1. Open Google Calendar on desktop — this can't be done from the mobile app.
2. In the left sidebar, next to Other calendars, click +.
3. Choose From URL, paste a feed URL, and click Add calendar.
4. It syncs to your phone automatically within a few minutes.

Apple Calendar / Outlook

Both accept the same URL: in Apple Calendar use File → New Calendar Subscription; in Outlook use Add calendar → Subscribe from web. Both honour the feed's hourly refresh hint, which Google largely ignores.

Google re-polls external calendar feeds on its own schedule — often every 12–24 hours, sometimes slower. That's fine for contests announced days ahead. If you want changes within minutes, use the push method below.

Want it instant instead?

Subscribing is read-only and refreshes at Google's pace. If you'd rather have contests pushed into a calendar you own — appearing within minutes, with your own reminders, and with renamed or cancelled contests corrected automatically — the repo includes sync.py, which writes directly to the Google Calendar API using a service account. It's a small Python script; I run it hourly from a Raspberry Pi.

github.com/asil-khalifa/codechef-calendar — MIT licensed.

How this one avoids dying the same way

There'd be something absurd about publishing a fix for abandoned calendar feeds that quietly becomes one. The failure mode is always the same — silence — so the design targets that specifically:

• Empty never overwrites good. If CodeChef's API fails or returns nothing, the generator exits with an error instead of publishing an empty calendar. A broken upstream can't blank your calendar.
• Failure is loud. A bad run turns CI red and sends email. That includes a third-party feed on this page going stale, so the recommendations can't rot unnoticed.
• Feeds change only when contests change, so the commit history is a genuine changelog rather than hourly noise — making it obvious at a glance when updates actually stopped.
• Events are keyed on contest code, not name. CodeChef ships duplicate names occasionally — START257 went out titled "Starters 255" — which would otherwise merge two contests into one.

One caveat I can't fully engineer away: GitHub disables scheduled workflows after 60 days without repository activity. If this page ever goes stale, that's the first thing I'd check.

Questions