Last updated 2 September 2026. Short version: this site has no accounts, no sign-ups and no database. Everything you do here stays in your browser, apart from the advertising described below.
Donka Puzzle Co. operates donka-puzzles.com. For any privacy question, email [email protected].
The Sudoku game uses your browser's local storage to remember three things:
This information is stored locally by your own browser. It is not transmitted to us, it is not stored on any server, and we cannot read it. Clearing your browser's site data will erase it, and doing so will reset your streak.
We do not ask for or collect names, email addresses, or any other personal information through this site. There are no accounts and no contact forms. If you email us, we have your email address and whatever you chose to put in the message, and we use it only to reply.
Our hosting provider, Cloudflare, processes standard server request data such as IP addresses in the course of delivering the site and protecting it from abuse. This is handled under Cloudflare's own privacy terms.
This site displays advertising served by Google AdSense. That advertising is how the site is paid for.
Opting out of personalised ads does not remove advertising from the site; it means the ads you see will be less relevant to you.
Where required, a consent notice is shown before non-essential cookies are set, and you can accept or reject personalised advertising. Your choice is remembered on your device and can be changed at any time by clearing your site data. The legal basis for processing under the GDPR is consent for advertising cookies, and legitimate interest for the security and delivery of the site itself.
We do not sell personal information in the ordinary sense of the phrase, though under the CCPA/CPRA the sharing of advertising identifiers with ad partners may be treated as a sale or share. You can limit this using the opt-out links above. You may also email us to ask what information relates to you and to request its deletion, though in practice we hold nothing beyond any email you have sent us.
This site is not directed to children under 13 and we do not knowingly collect information from them. If you believe a child has provided us with personal information by email, contact us and we will delete it.
If this policy changes, the revised version will be posted here with a new date at the top. Material changes to how data is handled will be noted clearly rather than folded in quietly.
Privacy questions go to [email protected] or via the contact page.