Privacy Policy
Left Hand Trainer ("we", "us") is a free, browser-based reaction trainer for PC gamers. The site is operated by Dan W., an independent individual developer, who is the data controller for the purposes of the GDPR and UK GDPR. You can reach us at any time at contact@lefthandtrainer.com.
This policy explains what we collect, why, and the choices you have. You can use the trainer anonymously — we do not require an account.
Your gameplay stays on your device
Your scores, streaks, reaction times, settings and personal bests are stored only in your browser's local storage on your own device. They are not uploaded to us. Clearing your browser data erases them.
Global leaderboard (optional)
After a round you may choose to submit a score to the public global leaderboard. Only if you click Submit do we store: the display name you type, your score and game stats (mode, accuracy, time), and your country. The country is derived from your network location at the country level only — we do not store your IP address or any more precise location. This information is shown publicly on the leaderboard, so please do not enter your real name or any personal information as your display name. Leaderboard data is stored using Supabase, our database provider. To have a leaderboard entry removed, email contact@lefthandtrainer.com with the display name and mode — we will remove it, no proof of identity required.
Anonymous training statistics
To understand how people actually perform on a keyboard — which keys are slowest, how quickly players improve — we collect anonymous, aggregated round statistics. When a round ends we record: the average reaction time for each key the trainer prompted you to press in that round, the mode, key set and difficulty you used, your accuracy, and a count of how many rounds have been played in this browser. The per-key figures cover only the keys the game asked you for, drawn from a fixed list of twenty-seven — nothing you type freely is recorded, and no text you enter anywhere on the site reaches this data. That holds when you build your own key set too: the editor only offers keys from that same fixed list, so nothing outside it can ever reach this data.
That round counter is read from your browser's local storage. It is not an identifier: it is not unique to you, and most records share a low number. But because it counts upwards, consecutive rounds played in the same browser can be matched to one another within our data — we would rather state that plainly than imply otherwise. What the record contains no version of is a name, an account, a device or advertising identifier, an IP address, or a cookie. There is nothing in it that identifies you, and nothing that can be joined to your leaderboard entries, to another browser, or to any other site.
One related detail, for completeness: if you play a custom key set, the record of that round shows which of those twenty-seven keys the round used, and an unusual combination is a more distinctive pattern than one of the built-in presets. It still names no person, device or browser, and it is still not readable from outside — but it makes rounds from one browser somewhat easier to group together within our data than a preset round would be, and we would rather say so than leave you to discover it.
This data cannot be read publicly. Unlike the leaderboard, the table is write-only from your browser: the public key this site ships is permitted to add rows to it and is not permitted to read them back. We may publish findings from it (for example "the median reaction time across all players for the 4 key"), always as aggregate figures with the sample size stated, never as individual records.
Where consent is legally required — the European Economic Area, the UK and Switzerland — these statistics are not collected at all unless a consent management platform has recorded your permission for them. We also send nothing from a browser with Global Privacy Control or Do Not Track enabled, and nothing when we cannot determine which country a visit came from. In every one of those cases the trainer works exactly the same.
Cookies and consent
We use cookies and similar technologies for two purposes: analytics (to understand aggregate traffic) and advertising (to keep the site free). Where consent is legally required — for example for visitors in the European Economic Area, the UK and Switzerland — advertising and analytics storage is denied by default on your device before anything loads. In practice that means we currently set no analytics or advertising cookies for those visitors and collect no training statistics from them; Google Analytics may still receive a cookieless signal that a page was viewed, which carries no identifier. If we begin serving personalised advertising in those regions we will ask for your consent first, through a Google-certified consent management platform that records your choice and lets you change it at any time through the options it presents. You can manage ad personalization at any time in Google Ads Settings. Strictly necessary storage needed for the site and your local scores is always active.
Analytics
Subject to the consent rules above, we use Google Analytics 4 to measure aggregate, anonymous traffic such as page views and country-level location. We do not use it to identify you. You can learn more in Google's Privacy Policy.
We also use Cloudflare Web Analytics, which counts page views without cookies and without building a profile of you, and Cloudflare's country signal to show a flag beside leaderboard entries. See Cloudflare's privacy policy.
Advertising
Subject to the consent rules above, we use Google AdSense to display ads. Google and its partners may use cookies to serve ads based on your visits to this and other sites. You can opt out of personalized advertising in Google Ads Settings, or learn more at Google's partner-sites policy. This information does not include your name, address, email or phone number.
Hosting
The site is hosted and delivered through Cloudflare, which processes standard technical request data (such as IP address and browser type) to deliver and secure the site, and provides the country signal used for the leaderboard flag.
Your choices and rights
Depending on where you live (for example under the EU/UK GDPR or the CCPA), you may have the right to access, correct or delete personal data, and to withdraw consent. You can: change your consent choice through the consent options presented to you where a consent banner applies; opt out of personalized ads via Google Ads Settings; clear your local data by clearing your browser storage; and request removal of a leaderboard entry by emailing contact@lefthandtrainer.com. We honor valid requests as required by law, free of charge.
Children
This site is not directed to children under 13 (or the minimum age in your country), and we do not knowingly collect personal information from them. Please do not submit personal information in the leaderboard name field.
Data retention
Leaderboard entries remain until you or we remove them. Analytics data is retained according to Google's default retention settings. Local data persists on your device until you clear it.
Changes to this policy
We may update this policy from time to time. Changes are posted here with a new "Last updated" date.
Contact
For any privacy question, to exercise a data right, or to request removal of a leaderboard entry, email contact@lefthandtrainer.com. We aim to respond to privacy requests within 48 hours. Full details are on the contact page.
The site is operated from the United States by Dan W. as an independent individual, not a registered company. Formal legal notices can be sent to the same address.