Privacy & attribution

How Chessility handles personal data. This notice is for visitors in the EU, including Slovakia. The service is in English, so this notice is too.

Controller

The controller is a natural person established in the Slovak Republic. Details are on the legal notice. Contact: the Feedback control on this site.

What we process

Game progress (wins, unlocks, rush scores, a short local history) in your browser via localStorage. Legal basis: the service you asked for (GDPR Art. 6(1)(b)). We do not upload PGN, FEN, or move lists.
Theme (light or dark) in localStorage. Same basis: needed to show the site as you set it.
Cookie / analytics choice in localStorage, so we remember Allow analytics vs Necessary only.
Feedback you send: the text, the page you were on, and an email only if you type one. Used to read the note and reply. Legal basis: Art. 6(1)(b) for the message you submit; Art. 6(1)(a) for an optional reply address. We do not use that email for marketing. Delivery uses a webhook (Discord or Slack) configured by the operator.
Abuse prevention: the feedback API stores your IP address in server memory for about 15 minutes to rate-limit spam. Legal basis: Art. 6(1)(f) (keeping the form usable).
Analytics only after you press Allow analytics: Vercel Web Analytics for page views and in-app actions (play, rush, feedback). Legal basis: Art. 6(1)(a). No PGN, FEN, or move lists. Withdraw anytime via .

Cookies and device storage

Under Slovak Act No. 452/2021 Z. z. on electronic communications (consent for access to your device), we only use non-essential storage after you allow it. Necessary storage (progress, theme, consent choice) does not need a prior opt-in because it is required to provide the trainer you opened.

Processors and transfers

Hosting is on Vercel. Analytics, if allowed, go to Vercel and (if configured) PostHog. Feedback may go to Discord or Slack. Those providers may process data in the United States. Where required, that relies on an adequacy decision (including the EU–US Data Privacy Framework for certified organisations) or standard contractual clauses. Prefer the PostHog EU host (https://eu.i.posthog.com) when you enable PostHog.

Retention

Progress and theme: until you clear this site’s data.
Consent choice: until you change it or clear site data.
Feedback: as long as needed to handle the note, then deleted from the operator’s mailbox / webhook destination.
Rate-limit IPs: about 15 minutes in memory.
Analytics (if allowed): according to Vercel and PostHog; stop new collection by withdrawing consent.

Your rights

You may request access, rectification, erasure, restriction, portability, and (for consent or legitimate interest) objection. You may withdraw analytics consent without affecting the trainer. To exercise rights, use Feedback. You may lodge a complaint with Úrad na ochranu osobných údajov Slovenskej republiky or your local EU data protection authority.

Chessility is not directed at children under 16.

Attribution

This demo stands on open tools and community assets:

Stockfish (source) and stockfish.js — chess engine (GPL-3.0)
chess.js — move generation and PGN/FEN handling
Piece sets include CBurnett (via Lichess / Wikipedia commons) and other public piece styles bundled with the project
UI built with Next.js, React, Tailwind CSS, and DaisyUI