Privacy notice

What we keep, and why

Last updated 30 October 2026

Most of the students who practice here are under 13, so we built Prep Platform to collect as little as we can, and to be unable to read what matters most. This page lists all of it, in plain words.

The short version

Your practice record is yours. It's saved to your account, where only someone signed in to the account can reach it. We don't look at it, and we never sell or share it.
When you finish a set for the first time, we learn which answers were picked. We never learn who picked them.
We never ask a student for anything about themselves. A parent or guardian makes the account with their email. Practice is saved to it once they pay, or for a short while during free time we give: without a payment, it's deleted 30 days after the free time ends.
No ads. No trackers. We never sell or share anything about you.

Your practice record

Everything you do while practicing is saved in your browser's storage on the device you're using. That includes:

your answers, scores and time on every set, your "not sure" marks, and the questions waiting in your revisit set;
the name you type into the app;
your grade and MAP Growth score, if you enter them, which decide where to start;
the notes and words you've seen, and settings such as checking answers as you go;
on the teacher pages, the classes and assignments a teacher sets up. Those pages are a preview: an invitation typed there is not sent anywhere.

One more item is there for the answer counts described below: a list of the sets already counted, so that each set counts once. It holds set names only.

You practice signed in, to an account that has paid for the practice or has free time; there's no practicing while signed out. Once the account is paid for, or has free time we've given it, the record is also saved to the account, and follows you to every device you sign in on. An account with no free time and no payment saves nothing: the record stays on the device until then. Signing out takes the record off that device; it stays in your account. The color theme stays with each device.

Cookies. So that our server can check what the account has paid for, a signed-in browser keeps two cookies for this site and sends them only with practice pages and questions: one holds the device's sign-in, and the other a list of the tests the account has paid for or has free, which our server signs and which lasts twelve hours, or until the free time ends. They do nothing else. The home page, the test pages and the answer counts never receive them, and signing out removes both. We set no other cookies.

What an account holds

An account is one student's. A parent or guardian makes it with their email and a password, or with Google, then chooses the practice and pays for it. The student signs in with the same email and password on their own computer or tablet. The practice opens once the account is paid for, or when we give it free time on a test, ourselves or with a code. Practice during free time is saved to the account. If no plan is paid for, that practice is deleted 30 days after the free time ends, and the account with its email. An account that never has free time or a payment is deleted 30 days after it was made.

For each account, we keep:

the email it was made with. It's the one thing about the account we can read. If it was made with Google, our provider also keeps the name and picture link Google sends with the email;
a check made from the password (a hash), never the password itself;
the practice record described above: answers, scores, times, notes and words seen, and the settings that follow the student between devices;
what's paid for: which books, on which plan, and until when; the ID our payment provider gives the account; and a record of the first payment as the parent's consent, with the version of this notice they saw;
free time we've given the account: which test, until when, and the code it came with, if any. A used code stays marked as used, with the test, the days and the date, after the account is deleted, so it can't be used again;
which devices are signed in, and the day each was last used. A device that isn't used for 180 days is signed out.

Who can see the record. Anyone signed in to the account, on any device. It's kept with our database provider, encrypted on their disks, and the site reaches it only for the account that's signed in. We don't look at individual records, use them to write questions, or show them to anyone; the anonymous answer counts below are what we learn from. The people who run the site could reach the database to fix a problem, and the law could require us to hand over what we hold.

How long we keep it. For as long as the account exists. Before the first payment, the record from free time is kept only until 30 days after the free time ends. Deleting the account removes it, its whole record and its email at once, stops its billing, and deletes its customer record at our payment provider. What's left is the mark on any code it used. Copies in our provider's backups are gone within 30 days.

Forgotten passwords. A forgotten password is reset by email. Nothing is lost: the practice history and everything paid for stay with the account.

What we receive: anonymous answer counts

The first time you finish a set, your browser sends us one short record. It says which set it was, how it was taken (as practice or as part of a full test, with answers checked as you went or at the end), and for each question:

which choice was picked, or that it was left blank, and whether it was right;
about how many seconds it took, and whether it was marked "not sure".

If you entered them on the MAP pages, the record also carries your grade, and on MAP sets, the band your MAP score falls in, such as 201–210. It never carries the exact score.

The record never contains a name, email, account, device ID, cookie, location, IP address or time of day, and it is never connected to an account, even when you're signed in. Nothing connects one record to another, even two from the same student. Retaking a set, working through a revisit set, and looking back over your answers send nothing.

Why we collect it. The counts show us questions that aren't working: a wrong answer nobody picks, a question that strong students keep missing, a set that is harder than its level says. We use them to fix questions and to write better ones, sometimes with the help of AI writing tools. Only the counts are used, and there is nothing about you in them.

How long we keep it. We delete each record two years after we receive it. Totals worked out from the records, such as "62% chose this answer," are kept for as long as the question is in use.

Because no record can be traced to a person, we can't find or delete one student's records. Nobody else can trace them either, and that is the point.

Who else is involved

These services help run this website. Each one receives your device's IP address and browser type when your browser talks to it, as every website's providers do. This is the full list:

Netlify: Hosts the website and stores the anonymous answer counts. It uses IP addresses to deliver pages and to protect the site from abuse, for example by limiting how fast one address can send records.
Supabase: Runs accounts: it stores the account details and the practice records described above, checks passwords, and sends the emails that confirm an address or reset a password. It keeps a log of sign-ins, with their IP addresses, to protect accounts.
Stripe: Takes payments. Stripe receives the account's email and the card details, what's being paid for or given free, and our internal number for the account, never anything the student practices. Stripe sends the receipts, and keeps payment records for as long as tax and accounting law requires, even after an account here is deleted. We never see the card number.
Google sign-in: Only if you choose Continue with Google. Google's sign-in script loads when you press that button, not before, and Google learns that you used your Google account to sign in here, as with any website's Google sign-in.
Google Fonts: Sends the typefaces the pages are set in.
jsDelivr: Sends the tool that displays math on the practice and teacher pages.

Outside of accounts, the IP address is the only identifier involved. It is used only to deliver the pages and keep the site running safely, never to contact, profile or advertise to anyone. We don't store IP addresses ourselves. We don't use analytics services, advertising networks, social media buttons or session recording.

What we never do

Show ads, or let anyone use what you do here for advertising.
Sell or share personal information.
Build a profile of you, follow you across other websites, or work out where you are.
Ask a student for a name, email, birth date, photo or location.

For parents and guardians

Your consent is the first payment for the practice, by card through Stripe, and Stripe's receipt confirms it. Until then, a student's practice is saved to the account only during free time we've given it, and only for a short while: if no plan is paid for, it's deleted 30 days after the free time ends. With no free time, nothing is saved to the account before that first payment. We ask only for your email. A student never gives us their own email, birth date or real name.

At any time, signed in on the account page, you can:

sign the account out of every device;
see your receipts, change your card, or cancel, on Stripe's billing page;
delete the account, which deletes its record and your email, stops its billing, and stops us collecting anything more.

To see the record, sign in on the sign-in page, where Download my record gives you a copy.

We don't share a student's record with anyone. When teacher accounts arrive, a teacher will see a student's record only after you approve it, and we will update this notice first.

If you believe your child gave us personal information without your consent, for example by making an account with their own email, contact us at the address below and we will delete it.

Your rights, wherever you live

Privacy laws in many places give you the right to ask what personal information a company holds about you, and to have it corrected, deleted or sent to you. Examples include the GDPR in the EU and UK, state laws in the US, PIPEDA in Canada and the LGPD in Brazil. Anyone signed in can download the account's record, and the account holder can delete the account, from the pages described above. For anything else, write to us and we will answer within 30 days. We can tell you what we hold about an account (the email, what's paid for, the consent record, the device dates and the practice record), and send you a copy. Asking will never change how the site works for you.

In the EU and UK. The personal data involved is account details, payment records, practice records, and the IP addresses our providers handle. Our legal basis for accounts and payments is providing the service you asked for and paid for, and for the rest, our legitimate interest in running a working, secure website. The anonymous answer counts are not personal data. Our providers are based in the United States, and their data processing terms cover the transfer. If you have a concern, you can complain to your data protection authority. In the UK, that is the Information Commissioner's Office.

In the United States. We do not sell or share personal information, and we don't use it for targeted advertising. If your browser sends a privacy signal such as Global Privacy Control, there is nothing for it to switch off, because we already treat every visitor that way.

Keeping it safe

Every page and every record travels over an encrypted connection (HTTPS), and our database provider encrypts what it stores. Passwords are kept only as a hash made by a deliberately slow calculation, so guessing them from a stolen copy of the database would take a very long time. Passwords need at least 10 characters, with uppercase and lowercase letters, a number and a special character. Each account reaches only its own record, and the tables behind it can't be read directly at all.

The answer counts are stored with Netlify, and only the people who maintain our questions can read them, with their own credentials. The code that runs accounts is served from our own site, never borrowed from elsewhere.

When this notice changes

We will post any change here and update the date at the top. If a change would affect children's information, we will post it before it takes effect and ask for a parent's consent before anything new about a child is collected.

The rest of the rules for using Prep Platform, including paying, renewal and cancelling, are in our terms of service.

Contact us

Write to us with any privacy question or request:

[Company legal name]
[Postal address]
[Phone number]
support@prepplatform.org