The CCC (short for Catalysts Coding Contest) is Europe's biggest on-site coding competition. Participants are challenged to solve a level-based coding game against thousands of others, worldwide - all at the very same time.

  • Any coding language accepted
  • Participate as a team or individually
  • Use your own computer with any libraries, tools and code snippets


As a participant you are asked to choose an event location, the actual place where you sit and code on the day of the contest. Participation is free, but space is limited. Make sure to reserve your seat in time. If there is no event location close to your home town or if it's fully booked, you can always participate online. Event locations are commonly provided by universities, schools or simply by ourselves - the organizer of the contest, aka Cloudflight.


Usually the CCC takes place twice a year: In spring and in autumn. The upcoming date is the 3rd of April 2020. If you like to plan ahead, watch out for the next dates on our social media channels or get a little reminder via email. Additionally we organize smaller events throughout the year.


Not ready?

Yes, there are still a bunch of things that you surely want to know. This page should summarize the most important ones. If you are looking for impressions to get a feeling for the event, you are welcome to check our social media channels! We share pictures and relevant information via:


The coding game is split into levels, you will be doing one by one. With each level the difficulty increases. The candidate reaching the highest level within the shortest amount of time wins. To accomplish a level you are asked to upload one or more specific answers to our submission platform, the CatCoder. Each wrong answer will be punished with penalty minutes. If you submit your source code after you have completed a level, you are granted bonus minutes. Hence, solving a level on paper is fine, but it won't get you a bonus. There is no need to worry about un-polished code though, we know that things get messy under pressure. You can use any coding language you fancy. Also, you are allowed to use pre-defined code snippets and libraries. Internet access is provided at all event locations, however, excessive downloading and/or streaming is forbidden. In case you have questions during or shortly before the contest, we are here for you via gitter. At any other time please contact us via team@codingcontest.org or Facebook Messenger.

2 contest types!


The #classic contest takes 4 hours and is suitable for coders of all skill-levels. Note, that only a few participants are able to accomplish the full coding game, as the difficulty increases with each level. There is no need to feel discouraged if you don't get so far - this is normal and intended. Btw, did you know that the CCC was initially created for a study?


The #school contest takes 2 hours and is designed for pupils and beginners. Ask your teacher about participation. We know many schools that organize excursions to the CCC or participate directly from the classroom. In Austria it is even supported by the ministry of education. How does that sound? A coding contest instead of just another lesson…

Team or single?


You rather join forces to tackle a challenge? No problem. Team up in groups of 2-3 (#classic) or 2-5 (#school). During the contest each team member is able to submit answers. Setting up a team is either done while registering for an event location or anytime after.


You are a master on your own? Very well! Register for an event location and you are all set. Don't forget, you can still challenge your friends to take part without having to work with them ;)

The day of the event

No matter what, you will be writing code. Apart from that, there are some interesting things to know. However, some parts might differ depending on the event location you are participating at. Therefore, please check your email regularly. We will keep you up-to-date with all general and location specific info. Here is the general agenda for both the #school and the #classic CCC:

  1. Pack your laptop and charger. Note that streaming services are prohibited.
  2. Arrive at least 30-45 min before the start of the contest.
  3. Don’t forget to register for a contest. Last minute registrations are possible until the start. However, we recommend you to register asap, due to a limited amount of seats.
  4. Set up access to the local network.
  5. Log in to gitter and send us a “Hello world” message in the Lobby ;)
  6. Start of the CCC (check your local timezone in the registration page)
  7. You will be coding for 4 (#classic) or 2 (#school) hours.
  8. End of the CCC
  9. Score summary and presentation ceremony

What's the upcoming game about?

Are you wondering what the next coding game is about? Our colleague, Bernhard Niedermayer, provides you with intel.

More questions?