Privacy and data

Who we are

Blundy is a chess coach in beta, published by its founder. Contact: [contact address to be completed before public launch].

What we keep

Your Chess.com and Lichess usernames and your public games there; your training progress (goal, reviews, training days); if you create an account: your email, or the identifier given by Google, Facebook or Lichess. No password: we store none.

Why

Only to analyse your games, show you why you lose and prepare your training. No ads, no resale, no commercial profiling.

Where your data is

Supabase database hosted in the European Union; website hosted by Vercel. Games are analysed on our own compute server or, without an account, directly on your phone, where they stay. AI-written explanations (later) will only receive chess facts, never your identity.

How long

As long as your account exists. If you delete your account, your profile, your progress and the analyses of your games are erased immediately. Your games stay public on Chess.com or Lichess, which are responsible for them.

Your rights

You can view, correct or delete your data at any time (GDPR): from “My progress”, “Delete my account” button, or by writing to us. You can also contact the CNIL.

Deleting your data

Sign in, open “My progress”, tap “Delete my account” and confirm. If you signed in with Facebook, you can also remove the app from your Facebook settings: write to us and we will erase your account.

Minors

In France, under 15, a parent's consent is needed to create an account. Parents can ask for deletion at any time.

Storage in your browser

Your progress, your session and, without an account, the games read on your phone are kept in your browser (local storage) so the app works. No advertising cookies. Audience measurement only keeps where your visit came from there, for as long as the tab is open, and, with your consent, its randomly drawn number (see “Audience measurement”).

Reminders (notifications)

Only if you turn them on. Your phone then gives us an encrypted delivery address, and Blundy keeps with it a small summary updated at each visit: your public chess username, your time zone, your usual hour, how many reviews you have per day, your blunders to fix, your rating, your goal, your Survival record and the kinds of reminders you turned off. Never your name, email or IP address. This summary is only used to write your reminders (“Your 57 blunders are waiting”), one a day at most, never at night.

You can turn reminders off at any time in your Profile, or in your phone's settings: the address and the summary are erased immediately (or at the first failed delivery). Reminders go through your phone's push service (Apple, Google or Mozilla), which only sees the text of the notification.

Audience measurement

To learn what really helps, the site counts what happens on it by itself: no outside tool, no advertising, nothing sold.

Without your consent, only anonymous counts, with no identifier at all: visits (and the site you came from, reduced to a name like “google”), the type of device (phone, tablet, computer), the language, the page (its template, never its exact address), page speed, site errors, and how many usernames given, games explained or exercises finished. We can't tell whether two visits come from the same person. Where your visit came from stays in your browser for as long as the tab is open.

Only with your consent (the “Can we measure what works?” banner): a randomly drawn number, kept in your browser for 13 months at most, links your visits and steps so we know whether the app makes you want to come back. This number is never linked to your username, your games, your account or your e-mail. Your choice is kept for 6 months, then asked again.

Under 15: choose “No thanks”; no per-person measurement.

Never collected: your username, your games, your e-mail, your IP address (only in memory, for a few moments, to block abuse), the exact address of pages or of the site you came from. Detailed events are kept for 180 days, then only their daily total.