Privacy notice

What we collect

• Account information: an account identifier from your chosen sign-in provider, your username, optional bio, avatar color, and account creation date.
• Solo practice: saved source code, execution format, progress and browser-reported attempt summaries.
• Match information: opponents, problem assignments, timing, outcomes, rating records, and submissions when server judging is enabled.
• Privacy requests: the type of request, your message, account identifier, timestamps, and handling status.
• Technical information: our hosting provider processes connection details such as IP address and request metadata to deliver and protect the service. Application errors record a request identifier, endpoint path, and error type.

Google sign-in checks a verified email and reads profile information to establish your account. We retain the provider identifier and initial display name, not Google passwords or access tokens. GitHub sign-in reads your public account profile. If email sign-in is enabled, we process your email address and temporary sign-in records. It is currently disabled.

Why we use it

We use account and match information to provide sign-in, matchmaking, saved history, competition results, and solo practice drafts, progress and the latest 50 local attempts per problem. Practice example results are browser-reported and unverified. Where GDPR applies, this processing supports the service you request under our terms. We use limited security and operational information for our legitimate interests in preventing abuse and maintaining reliability. Optional device storage relies on your choice in Cookie settings.

We do not sell personal data or use it for advertising. We use cookie-free Cloudflare Web Analytics to measure visits, page views and page performance outside the EU/EEA. Visits are not an exact count of unique people. Browser blockers may prevent collection. We do not offer marketing mail subscriptions. We do not send your code to an AI provider.

What other players can see

Your connection contributes to an aggregate online count while signed in. We do not display a list of online accounts. Your username, avatar color, rating, and statistics may appear in matches and the public leaderboard. Match participants can see their shared result. Your bio is currently shown in your own profile editor. Local Python code drafts and browser execution output stay on your device unless you deliberately send them to a server feature.

Services we use

Cloudflare hosts the website, API, database, and multiplayer rooms. Google and GitHub handle sign-in when you choose them. If email sign-in is enabled, Resend delivers sign-in messages. Follow their privacy notices for their own processing: Cloudflare, Google, GitHub, and Resend.

These providers may process information outside your country, including outside the EEA or UK. We have not restricted the service to EU-only infrastructure. Contact us for information about applicable provider agreements and transfer safeguards.

How long information stays

Account profiles and match records currently remain while the account is active; there is no automatic inactivity deletion. An erasure request starts a review of account, database, multiplayer-room, and backup records, including records shared with opponents. We explain any legal or dispute-related reason to retain information rather than promising immediate removal from every system.

Sign-in sessions expire after seven days; OAuth and email-link records expire after ten minutes. Expiry prevents further use. Hourly maintenance removes expired sign-in and rate-limit records; delays are possible during outages. Host log and backup retention follows the configured Cloudflare service settings. Contact us for the current settings. Duel drafts remain on the device until cleared or optional storage is disabled. Solo drafts remain in your account. Practice retains the latest 50 example-run attempts per problem; new attempts replace older history entries. Custom-run input and output are not stored. Privacy requests remain until handled and retention is reviewed.

Your choices and rights

Edit your username and bio in Profile. Use Cookie settings to allow or withdraw saved preferences, or clear local drafts below. Signed-in users can download their account records and submit requests for access, correction, erasure, restriction, or objection on our contact page.

Where GDPR applies, you can exercise these rights, request portability where applicable, and complain to your local data protection authority. We aim to respond within one month, subject to applicable law and permitted extensions. We may need to verify identity. We never need your password for a request.

Children and changes

This beta is intended for adults aged 18 and over. Please contact us if a child has created an account. We will update this notice when our data practices change and provide notice of material changes through the service.