Privacy policy

Short version: no accounts, no personal data collection. Your code runs in your browser and never leaves your device.

Last updated: 2026-10-29

What stays on your device

• Your code. Everything you type in the playground or practice editor is executed locally by JavaScript in your browser. It is not uploaded, stored or seen by anyone but you.
• Your drafts. The editor saves your code in your browser's localStorage. Clearing your browser data removes it; we never receive it.
• Your inputs. Test inputs and judging also happen locally.

What a website can't avoid

Like essentially every website, the hosting provider (a static-hosting CDN) technically processes anonymized request logs (IP addresses included) for security and abuse prevention, as described in the provider's own policy. We don't use analytics cookies, sign-in, or any cross-site tracking.

Advertising and third-party cookies

This site may display advertising through Google AdSense. Third-party vendors, including Google, use cookies to serve ads based on your prior visits to this website or other websites.

• Google's use of advertising cookies enables it and its partners to serve ads to you based on your visit to this site and/or other sites on the Internet.
• You may opt out of personalized advertising by visiting google.com/settings/ads, or opt out of third-party vendor cookies at aboutads.info/choices.
• Visitors in the EEA, UK and Switzerland are shown a consent choice before any personalized advertising loads.
• Advertising never runs inside the code editor or the judging panel.

If advertising is not currently enabled, no advertising cookies are set and no ad scripts are loaded.

Changes

If this policy materially changes, the date above changes with it. Questions: use the feedback link (or the address shown in your mail client when it opens).