Privacy policy.
Last updated October 28, 2026
Who we are
Cortex Chess (cortexchess.com) reviews your chess games and helps you learn from them. It's run by two chess players, known on Chess.com as GaboCoronado. Opens in a new tab. and dan3lson. Opens in a new tab.. This page explains what we collect, why, and who else sees it.
Here's the short version:
- We collect what we need to run your account and review your games.
- We never sell your information.
- When you sign up after seeing one of our ads in ChatGPT, we share a hashed copy of your email with OpenAI so they can tell us which ad worked. See Your choices for how to stop it.
- You can ask us to delete your account and everything in it at any time.
For questions or requests, email cortexchessapp@gmail.com. A real person reads every message.
What we collect
We collect only what you give us, what your chess sites already show publicly, and what the site needs to work.
Your email address
Where it comes from: You, when you sign up.
Why we need it: To sign you in, reset your password, and send you emails about your account and your games.
Your password
Where it comes from: You, when you sign up.
Why we need it: To sign you in. We store it hashed, so even we can't read it.
Your Chess.com and Lichess usernames
Where it comes from: You, when you sign up.
Why we need it: To find and import your games.
Your games
Where it comes from: Chess.com and Lichess, where they are already public.
Why we need it: To review them and show you where you can improve.
Your display name
Where it comes from: Your chess username, unless you change it.
Why we need it: To show who you are to the friends and coaches you share with.
Your time zone
Where it comes from: Your browser.
Why we need it: To count your free daily reviews by your own day.
Notes, comments, lines and bookmarks
Where it comes from: You, as you use the site.
Why we need it: To save your work and show it to the people you share it with.
Friends, coaches and classes
Where it comes from: You, when you accept or send an invite.
Why we need it: To let the people you choose see your games.
How you found us
Where it comes from: The link you arrived on, such as an ad or a friend's invite.
Why we need it: To learn which ads and invites bring people in.
What you do on the site
Where it comes from: The site, as you use it (for example, opening a review).
Why we need it: To see which parts help people, and fix the ones that don't.
Purchases
Where it comes from: Our payment company.
Why we need it: To give you what you paid for. Your card number goes to the payment company, never to us.
We don't ask for your real name, address, phone number, or birthday.
Who we share it with
We never sell your information. We share it only with the service providers that help us run Cortex Chess, and only what each one needs.
Ads measurement (OpenAI)
What it gets: The pages you visit, the moment you sign up, a code from the ad you clicked, a random ID for your browser, and a hashed copy of your email.
Why: To tell us which of our ChatGPT ads brought you here, so we can reach more players like you.
An AI company
What it gets: Your games, including the usernames in them.
Why: To write the coaching in your reviews.
A payment company
What it gets: Your email and what you are buying. Your card details go straight to them, never to us.
Why: To take payments.
An email delivery company
What it gets: Your email address and the emails we send you.
Why: To deliver our emails.
A visit counter
What it gets: Page visits, counted without cookies or anything that identifies you.
Why: To count visits to the site.
An error tracker
What it gets: Error reports from our servers, set up to leave out your IP address and personal details.
Why: To find and fix problems.
A hosting company
What it gets: What we store, because our servers and database run on their computers.
Why: To run the site.
A font service
What it gets: Your IP address, when your browser loads our fonts.
Why: To show the site's lettering.
Chess.com and Lichess
What it gets: Your username, when we ask them for your public games.
Why: To import your games.
If you want to know which company fills any of these roles, email us and we'll tell you.
About the OpenAI ads. We run ads in ChatGPT to reach more chess players who want to learn from their games and get better. To find out which ads actually do that, we measure sign-ups. When you sign up, OpenAI's code on our page hashes your email address in your browser before sending it. Hashing turns your email into a code that can't be turned back into the address, so OpenAI never receives your email itself. If you have a ChatGPT account with the same email, OpenAI can match the two (OpenAI calls this advanced matching) and tell us which ad you saw. That lets us spend our ad budget on the ads that bring in players and stop the ones that don't. OpenAI says it does not currently use this information to personalize what you see. We don't sell your information to OpenAI or anyone else.
People you choose. When you share a game or join a class, the people you share with see that game, your notes on it, and your display name.
If the law requires it. We may share information when the law requires it, or to protect someone's safety.
Cookies and browser storage
We use a few cookies and saved browser settings. Most just make the site work. OpenAI's two are for ads.
Keeping you signed in
Who sets it: Us
How long it lasts: 30 days.
Remembering how you found us: the first link you came in on, the ad you clicked, or a friend's invite
Who sets it: Us
How long it lasts: Up to 30 days for an ad. An invite lasts until you sign up.
Saving what you're in the middle of, like a game you're typing in, and whether you've seen our tips
Who sets it: Us
How long it lasts: Until you close the tab, or until you clear your browser.
Measuring our ChatGPT ads
Who sets it: OpenAI
How long it lasts: Two cookies: one for 30 days, one for 365 days.
Your browser may delete any of these sooner. You can clear them at any time in your browser's settings. Clearing them signs you out.
Your choices
Delete your account. Email cortexchessapp@gmail.com from the address you signed up with. We'll delete your account, your games, your notes and comments, and everything else tied to it within 30 days, and write back when it's done.
Get a copy or fix something. Email us and we'll send you a copy of what we hold about you, or correct anything that's wrong.
Stop the ads measurement. Your browser's tracking protection or an ad blocker stops OpenAI's code from running, and the site works the same without it. Clearing your cookies removes the two OpenAI cookies.
If you live in the European Union or the UK, you also have the right to object to how we use your information, to limit it, and to take it with you. We use your information to provide the service you signed up for. You can complain to your local data protection authority.
How long we keep it
We keep your account and everything in it until you ask us to delete it. Records of what people do on the site are deleted after one year. Payment records are kept as long as tax law requires.
Children
Cortex Chess is not meant for children under 13. If you're under 13, please don't sign up. If we learn that a child under 13 has an account, we'll delete it. A parent can email us to ask.
Changes to this policy
When we change this policy, we'll update the date at the top. If a change affects how we use information we already have, we'll email you before it takes effect.
Have a question this page doesn't answer? Send us a message.