Privacy

Without an account

Your practice history, bookmarks, mock exam progress, scratchpad notes, your light or dark theme choice and when you last put off the offer to keep your progress are saved in your own browser using localStorage. They stay on the device you used and are not transmitted anywhere. An error report you write while signed out opens in your own email app, and is sent only if you send it.

If you create an account

An account is optional. Every part of this site works without one, and progress then stays in your browser.

If you sign in, these things are stored against your account: your email address, which is how you sign in again; a display name, taken from Google if you used it and editable on your account page; your learning progress, meaning which questions you have answered, whether you got them right the first time and since, how many tries and how long it took, whether you opened a hint or the solution, how sure you said you were before checking, when a wrong answer matched a known slip, which slip, when you walked a solution step by step, the step you said you did not have, and, for a question you found hard, when it is next due for review; a timestamped log of each answer you send, saying whether it was right, whether you opened a hint or the solution and how long it took, but not what you typed; your bookmarks; your mock-exam results, including the final answer you gave to each question so the review works on any device, and how long each question was open and in what order, so the pacing can be shown; the days you practised, with how many answers and for how long, so a streak can be counted; and, when you download a paper as a PDF, which paper and when, so a copy can be traced if it is shared. The file itself carries your name and email address on every page.

The answers you type while practising and your scratchpad working are not stored. They are not needed to measure progress, and your working out is yours.

Signing in with Google shares your email address and name with this site. It does not give Google any of your practice history. An error report you send while signed in is stored with your account, along with the page you sent it from, so a reply is possible; it survives, without a name, if the account is deleted.

Supabase, which runs the sign-in, keeps the network address and browser each sign-in came from, and, if you sign in with Google, the web address of your Google profile photo. This site does not use them.

While you are signed in, this browser also keeps your email address and name, a copy of your progress so pages open quickly, and any changes not yet sent to your account. Signing out removes the copy, the name and address, your scratchpad notes and any paper in progress. Changes not yet sent stay, and are sent the next time you sign in here.

The data is held by Supabase, the database service this site runs on, in a region chosen when the project was created and named in the setup notes. It is not sold, shared or used for advertising.

What is measured

Two measurements run, both from Vercel. Web Analytics counts page views, so it is possible to tell which topics are being used. Speed Insights records how long a page took to become usable, so a slow page can be found and fixed. Neither sets a cookie, builds a profile, or follows you to other sites.

Between them they record the page address, the referring site, an approximate country, the kind of device and connection, and page-load timings, never the contents of a page. Sign-in pages have their web addresses stripped of everything after the path before a page view is recorded.

Seven events are counted as well, so it is possible to tell whether the sign-in flow works: a sign-in started (and whether by Google or email), a sign-in completed, progress imported (and how many items), the keep-your-progress prompt shown, that prompt dismissed, an account deleted, and a paper downloaded as a PDF (and which kind of paper). None carries your email, name, a question or anything you typed, and measurement is kept entirely separate from your account.

When something on a page fails in your browser, a report goes to the database this site keeps, so it can be fixed: the kind of error and its message, the path of the page without anything after it, the version of the site, and the name of your browser and whether it is on a phone. Nothing you typed, no account and no network address go with it. When a page or a printed paper fails on the server, the same is kept: where it failed and the message, the path and the version, and nothing about who asked. The same error on the same page is counted rather than stored again, and every report is deleted after 30 days.

What is not collected

There is no advertising, no advertising network, and nothing that identifies you across sites. No server receives the answers you type while practising or your scratchpad notes, with or without an account. No password exists to be leaked: sign-in is by Google or a single-use emailed link.

Removing your data

Clear all progress on the progress page removes the stored history, in your browser or in your account; the record of papers printed for the account stays until the account is deleted, since each printed copy carries its serial. Clearing site data for this domain in your browser removes everything held locally, including scratchpad notes and saved exam sessions. Delete account on the account page removes the account and everything attached to it, immediately and permanently; a copy can be downloaded first from the same page.

Fonts

Typefaces are served from this site rather than fetched from a third-party font service, so loading a page does not reveal your visit to anyone else.