Privacy

Last updated 13 October 2026.

What is stored, and where

This site saves the following in your browser's local storage, under names that begin with rb::

That data stays on your device. It is not uploaded, not synced between your devices, and nobody else can see it.

Clearing this site's data in your browser deletes all of it. Private or incognito windows throw it away when you close them. If your browser blocks local storage completely, the tests still work. You just get no saved history, and the page tells you so.

What is not collected

There are no accounts, so we never ask for a name, email address or password. Your personal records (bests, streaks, achievements) stay in your browser and are never sent.

The anonymous statistics record

By default, one thing goes to our own server. When a test finishes, the site stores an anonymous statistics record that holds:

That is the complete list. We keep no IP address, no user ID and no exact time, so no score can be traced back to a person.

These records feed the statistics table on each game page, which appears once a device type has 30 runs. Later, when a game has enough runs to be a fair baseline, they will also give a "top N% of runs measured here" line.

Leaderboards

Leaderboards are opt-in. If you choose to submit a nickname after a run, that nickname and score are displayed publicly on that game's board. There is no account. The board keeps only the name you type, the score, and whether you played by mouse or touch, which shows as an icon.

Every game has its own board, with separate boards for each difficulty and, for typing, each language. Boards build up with no resets for now, and a season change will be announced in advance. Once your nickname is on a board, later scores are sent under that nickname automatically, and the board keeps your best one. If you never submit a name, nothing about you appears anywhere.

Group rooms

Group rooms work the same way. When you join a room someone shared with you, your nickname and your real-attempt score appear on that room's board, where anyone with the link can see them. Practice runs are never sent to the room.

A room stays open for 24 hours. Once it is 30 days old, a daily cleanup deletes it along with all its names and scores, so it is gone within a day of that point.

Analytics and session recording

Google Analytics

This site uses Google Analytics 4 to count page views and see which tests people actually play. It sets cookies in your browser with names that begin with _ga. It reports to Google the page you are on, a rough location based on your IP address, and basic device and browser details. Google Analytics 4 does not log full IP addresses.

We also send it a few events of our own. When you start a test, it gets the test name, the difficulty mode, and whether it was the daily, a challenge or a group room. When you finish one, it gets the test name, the mode, whether it was the daily, and your score. Sharing a result or sending a challenge link sends an event that names the test and how you shared it, and a finished challenge sends whether you won. None of these events contains your nickname or anything else that names you.

KakaoTalk sharing

The KakaoTalk share buttons appear on the Korean pages: on a result, in a group room and in the footer. The Kakao SDK loads only when you press one. It opens the share window and receives only the card you are sharing: a title, a short line and the link. On a result card, the title holds the test name, your score and your nickname if you typed one.

Microsoft Clarity

The site also uses Microsoft Clarity, which goes further than page counts. Clarity records how a page was used (where the pointer moved, what was clicked, how far the page was scrolled). It replays that as an anonymous session so we can see where people get stuck.

Leaderboard nicknames are marked in our code so Clarity hides them in recordings, and Clarity hides what you type into input boxes. It is not loaded on the test pages or the Full Brain Test, so it never records a test being played. Clarity sets its own cookies and may combine what it collects with other Microsoft data, as described in the Microsoft privacy statement.

How to opt out

If you would rather not be recorded or counted, any of these works:

Blocking any of these changes nothing about the tests, because nothing here depends on those scripts loading.

Advertising

No ads are shown yet. The site already carries the Google AdSense loader while our application is reviewed. Once ads run, Google may set advertising cookies and use them as described in Google's advertising policy. Ads will never sit inside or beside the game panel, and blocking them does not affect the tests.

Server logs

Cloudflare delivers this site. To serve pages and block abuse, it handles standard request details such as your IP address, your browser type (user agent) and the address you asked for. That processing is Cloudflare's, covered by their own privacy documents. We do not use it to build any profile of you.

How to clear what is stored

Almost everything this site keeps about you lives in your own browser, so you can delete it yourself without asking us. Clearing this site's data in your browser settings deletes your bests, streaks, achievements, challenge-link and room entries, the last-visit snapshot, your sound, theme and language choices, and the nickname you last used. There is no account to close.

A few things are not in your browser, so clearing it does not remove them. Group room names and scores are deleted within a day of the room turning 30 days old. A leaderboard entry you chose to submit stays on the board under the nickname you typed. The anonymous statistics record for a finished run stays in the count.

Neither of those last two is linked to you or to your browser, so we cannot look up which rows are yours. If you want a leaderboard entry taken down, email the address below with the test and the nickname, and we will remove it.

Children

This site is not made for children, and it collects nothing that could identify anyone of any age.

Contact

Send any questions about this page to ysc9550@gmail.com.