Privacy

We hold no information about any child

This is the section to send to your IT department, and it is short because the answer is short. We have no student names, no class lists, no scores, no grades, no attendance, no identifiers, and no free-text field where any of those could be typed and stored.

The worksheets are built inside your browser. The problems, the numbers, the pictures and the answer key are all generated on your own computer and turned into a PDF there. No worksheet is sent to us, and there is no copy of one on any server of ours to be requested, breached, subpoenaed or sold.

COPPA governs collecting personal information from children under 13. We collect none, from anybody, of any age. FERPA governs education records held by schools and by contractors acting for them; we hold no education records and are not acting as a school official for anyone. State student-privacy laws address services that gather student data; there is none here for them to attach to.

Including the title box. Teachers do sometimes head a worksheet with a child's name, so the title you type and the instruction line you write are held in the part of the web address after the "#" symbol. Browsers never send that part to a server. It is not in the request, not in our logs, and not passed on to any site you click through to — and a link you share still opens the worksheet exactly as you set it up, because the other browser reads it without asking anybody.

What we measure about the site

Two things, and this section says exactly what they are. We need to know whether anybody is using this and which worksheets are worth building more of. Neither measurement involves an account, and you do not need one to use the site.

Page views. These are counted by Vercel Web Analytics, which is part of the company that hosts the site. Its documentation says it does not use cookies to identify visitors: instead a visitor is identified by a hash made from the request, which is reset every day, so the same person on two days is two visitors and the same person on two websites is unconnected. What is recorded with a page view is the time, the address of the page, where you arrived from, an approximate location from your connection, and your browser, operating system and device type. Vercel states that these records are not associated with an IP address.

We do not know what goes into that hash. Vercel does not publish it, so we will not tell you it is one thing rather than another. What we can tell you is that it is gone within a day, by their account, and that nothing on our side ever sees it.

Which worksheets are downloaded. This one is ours, and it is deliberately blunt: a row is the name of the worksheet, which part of the set it was, and the time. There is no column for who, because we did not make one. Two downloads by the same teacher are two unrelated rows. It can tell us that the fraction sheets get printed and it cannot tell us who printed them, and that is the whole design.

Neither of these records anything you type. The worksheet still never leaves your browser, and the title box is still held in the part of the address a browser does not transmit, as above.

What we collect about you

Only if you make an account, which nothing on the site requires. Every worksheet downloads without one. If you do sign up, this is the whole of it:

• The email address you sign in with. If you sign in with more than one address we link them to the same account, so you keep one history rather than two.
• The date the account was created.
• If you sign in with Google, your name and the web address of your Google profile picture. Google sends these along with your email address, and our sign-in provider stores them. Nothing on this site reads them or shows them, and they go nowhere else.
• If you chose a password rather than signing in with Google or an emailed link, a scrambled one-way version of it — never the password itself. It is stored by our sign-in provider, and neither we nor anybody holding a copy of the database can read it back. We never see the password you type.
• Older accounts may also have a timestamp for each worksheet downloaded while downloads were limited. That record is an account reference and a time, and nothing else — not which worksheet, not which standard, not which options. Nothing is being counted against an account any more, so no new ones are written.

Nothing is for sale at the moment, so nothing takes a payment. The payment system is still wired up for later: if it is ever switched on, Stripe handles the payment and holds the card details, and we receive a customer reference and whether a subscription is active. We never see or store a card number.

What we do not do

No advertising, and nothing that follows you. No Google Analytics, no Facebook pixel, no ad network, no session recorder, no remarketing tag, and nothing that tries to recognize you on another website. The two measurements above are the complete list, and they exist so we can fix what is broken and build more of what gets used.

We do not build a profile of what you teach. We can see that a worksheet was downloaded; we cannot see that you downloaded it, and we have not built anywhere to keep that even if we wanted to.

We do not sell, rent or share personal information with anybody for advertising or any other purpose. There is no circumstance in which we would sell an email address.

Nothing you do here is sent to a language model. Every worksheet, every number and every answer key is produced by ordinary code that always gives the same answer, which is also why the keys can be trusted.

Cookies

The only cookies set are the ones that keep you signed in, and you only meet them if you make an account. They are strictly necessary for signing in to work, they carry no advertising or tracking purpose, and signing out clears them.

The page-view counting does not use cookies to identify visitors — that is what the daily hash described above replaces, and it is what their documentation says. Nothing else on this site stores anything in your browser unless you sign in, which is a thing we can check about our own code and have.

This is why there is no cookie banner. A consent pop-up exists to ask permission for the cookies you would refuse, and there are none of those here. A banner would be a piece of theatre asking you to agree to nothing.

Who else handles your data

Five companies, each doing one job, and no others. They are named rather than described, because a school checking us out should not have to ask which ones:

• Vercel hosts the site and counts the page views described above. As the host it keeps ordinary web-server logs — the address requested, the IP it came from, the time — for a period they set. The part of an address after the "#" is not in those logs, because the browser never sent it.
• Supabase stores the account rows listed above and the worksheet download counts, holds the scrambled password if you set one, and writes the sign-in, confirmation and password-reset emails — which it then hands to the email provider below to deliver.
• Our email provider delivers those messages to your inbox, and is the only company here that exists solely to do that. It sees the address it is sending to and the contents of the message — which, for a sign-in email, is a link or a code — and keeps a record of both for a short period so that a message that failed to arrive can be traced. It is not sent anything about the worksheets you make, and we send no marketing of any kind.
• Google, and only if you choose "Continue with Google" rather than a password or an email link. If you use either of those, Google is not involved.
• Stripe, and only if there is ever something to pay for and you pay for it. Nothing on the site currently takes a payment, so for now Stripe hears nothing about anybody.

No data broker, no ad network, no marketing platform, and no AI provider.

How long we keep it

Account details are kept until you delete the account, at which point they and the download timestamps attached to them go with it.

The page-view counts are held by Vercel. Their documentation guarantees the figures stay viewable for a period that depends on the plan we are on, and says they may keep the data for longer than that — so we cannot honestly give you a deletion date, and we are not going to invent one. There is nothing in those records that points at a person.

The worksheet download counts are ours and we keep them. They are a worksheet name, a part and a time, with nobody attached, so there is nothing in them to expire.

Server logs are kept for whatever period our hosting provider sets; we do not extend it or copy them anywhere.

Sign-in and password-reset emails are held for a while by the company that delivers them, so that a message which never arrived can be traced. That period is theirs to set rather than ours, we do not extend it, and we do not copy those messages anywhere else.

What you can ask for

Write to privacy@differentiatedmath.com and you can ask us to send you a copy of everything we hold about you, correct it, or delete it and close the account. We will do it within 30 days and will not ask you to justify the request.

These apply to everybody, wherever you live. Various laws grant some people these rights and not others; sorting our users into those buckets would cost more than simply giving everyone the same answer.

The site is operated from the United States and the data described above is stored there. If you are writing from elsewhere, that is where it lives.

Changes to this policy

If we change what we collect or who handles it, we will update this page and — where the change matters — email account holders before it takes effect. The date at the top is the version you are reading.

Contact

Questions about any of this, including from a school assessing whether staff may use it, go to privacy@differentiatedmath.com. A real person reads it.