Watch the game rules in one of these supported languages

Watch the Krudoku Promo Video !

Watch the Interview on Dutch Television !

News Blog

Krudoku 3.0 released in App Store


4 years ago

We are proud to announce that Krudoku 3.0 can be downloaded now from the App Store! – ios7 design – challenge a random opponent has improved – find a player who is also searching for an opponent – share scores … Continue reading

Volkskrant Review


5 years ago

Krudoku has been reviewed by de Volkskrant, one of the main Dutch news papers. They call it ‘NumberFeud’, being a very addictive new muliplayer Sudoku board game. It can be compared with the famous WordFeud app, but this one is … Continue reading

Play tournaments on


5 years ago

Since today it is possible to play Krudoku tournaments on It was already possible for WordFeud, MindFeud and Angry Words. But now Krudoku has been added so you can start your own tournaments now ! Register for free on … Continue reading

Review from


5 years ago

We received a very awarding review from, the number 3 ranked app review site on the internet! “It’s not hard to see why the game is so popular once you start playing it. Krudoku is packed with exciting gameplay … Continue reading

Bug finder rewarded


5 years ago

One of the players in Krudoku found a major bug, which she posted to us via the website. To show our gratitude today we visited her and rewarded this with a very nice apple pie! In the very first move … Continue reading

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About Us

HelloApps BV is brand new privately held company in the Netherlands. It is established with the aim of making Apps for business or commercial use. Our first PVP, multiplayer, iOS, mind cracking board game is Krudoku.

Jaap-Jan Hellinga is CEO and app developer. He worked for almost 15 years at Atos in the Netherlands as an IT-specialist. Brainstorming with his wife about a new game with digits finally has led to Krudoku as it is. A crucial part of creating a very stable and fast game was the feedback of our test team and the use of TestFlight. We’re very grateful that the testers of various backgrounds and ages have been testing Krudoku continuously for almost 4 months now.

We already have lots of new ideas for new Apps. With our IT technical background we are more than able to make any high quality App you want.

If you have an idea, suggestion or if you have a business opportunity please contact us with the contact form below. We are looking forward to hear from you.


If you have a question, remark or suggestion please leave a message. In case you want to report a bug, or you’d like to have new functionality added to the Krudoku app please also leave a message.