Privacy

If You Sign In

You sign in with GitHub or Google. We then keep:

• the provider's ID for your account: not your email address, not your name, and never a password;
• the display name you choose, shown on the ranking and your public profile;
• your progress: which problems you completed, your points, the hints you revealed, and each answer you checked (right or wrong, and when), for the points penalty and cooldowns;
• your best passing answer for each problem, visible only to you;
• which problem you were last on, for a Continue link.

A ftp_session cookie keeps you signed in for 30 days after your last visit. We store only a scrambled (hashed) form of it. Sign Out deletes it.

As a Guest

Nothing that identifies you. Your browser keeps a few small things for your convenience, and they never leave it:

• a theme cookie with your light or dark choice;
• for the current tab only, the hints you've revealed and your wrong attempts, so a reload doesn't reset them;
• which sections of a problem statement you closed.

API Keys

Live problems use your own API key. It stays in your browser and goes straight to the provider you chose. It never reaches our server, and we never store it.

No Trackers

The site uses no advertising or analytics trackers, and its fonts are served from this site, not from a third party.