Privacy Policy

This policy covers unnamed (www.998244353.best) and its browser extension CC for Web. Last updated: 2026-10-06.

In one paragraph

There are no accounts here. Your code, problems and hand-written test cases stay in your own browser and are never uploaded to our servers. The only thing that is ever uploaded is the preference profile you explicitly push with “Upload local settings” — and that profile is publicly readable.

What the site keeps in your browser

All of the following lives in this browser on this device only. The site cannot read it and keeps no copy:

• Editor preferences (theme, shortcuts, UI scale, sidebar position and split ratio, time limit) — in localStorage.
• File tree and file contents (your problems, code and notes) — in IndexedDB.
• Caches such as precompiled headers — also in IndexedDB.

Clearing your browser data removes all of it. We have no way to get it back.

The optional cloud sync

It only happens when you click “Upload local settings”, and only preference items are uploaded: theme, shortcuts, UI scale, sidebar position, split ratio and time limit.

Once uploaded, that profile is publicly readable: anyone who knows your Codeforces handle can fetch the same profile at an address of the form https://www.998244353.best/your-handle, with no login required. Clicking “Upload local settings” therefore means agreeing to publish that profile.

The judge server address, your hand-written test cases, the file tree and file contents are never uploaded. To have an uploaded profile deleted, see the contact details below.

When your code leaves your device

Only in these two cases, both of which you trigger yourself:

• When you switch to an external judge service. If you switch the judging engine to Piston or Judge0, your code is sent to the service address you entered yourself. That deployment is yours and its data handling is up to you; this site is not involved and keeps nothing.
• When you use the browser extension to grab a problem. The extension reads the current problem page and delivers the statement and samples to the target you picked (a tool running on your own machine, or the editor on this site you are already using). It does not go through our servers.

With the built-in local WASM sandbox, your code never leaves your device at all.

What the browser extension reads

• Only when you click the extension icon or press its shortcut, it reads the URL of the current tab to decide whether the page is supported.
• On supported problem sites, it reads the statement and sample text on that page.
• When you open a supported problem site, the extension asks this site's page whether the samples for that URL still need filling in; it only reads the statement and samples if this site answers yes. It does nothing else on those pages, and you can turn it off per site from your browser's extension permission settings.
• It does not read other tabs, does not record browsing history, and collects no personally identifying information.
• What it parses is sent only to the target you chose, and never through our servers.

What we do not do

• We do not collect names, email addresses or phone numbers, and there is no sign-up.
• No advertising, no analytics tracking, no profiling.
• We do not sell, rent or share any data with third parties.
• We never upload any file without your knowledge.

Third-party services

• The site is hosted on Vercel and its static assets are distributed through Cloudflare; access logs are handled by those providers under their own privacy policies, and we keep nothing extra.
• The three open-source monospace fonts bundled with the code area (JetBrains Mono / Fira Code / Cascadia Code) are downloaded only when you select one under Settings › Editor › Font.
• See Third-party components and licences for the full list.

Children

This site is not aimed at children under 13, and we do not knowingly collect their personal information.

Changes to this policy

When this policy changes we update the “Last updated” date at the top of the page. Material changes to our data practices will be called out on the site as well.

Contact

For questions about our data practices, or to have an uploaded profile deleted, please open an issue on GitHub:

• Site and cloud sync: wasm-oj-frontend
• Browser extension: cph-companion