Privacy policy.

1. Who this is about

This policy describes how Armaan Singh, a sole proprietor trading as Pencils Down Labs(“we”, “us”), handles information about people who visit this website, make an account on it, or buy access to it. It sits alongside the terms of service, which describe what you are buying.

It covers this website only. The printed book is sold through Amazon, and what Amazon collects when you buy it is between you and Amazon, under their policy rather than this one. Nothing about your purchase there reaches us except what you choose to tell us when you verify your copy, described in section 3.8.

2. The short version of how this site is built

Two facts explain most of what follows. The first is that there are no passwords here: you sign in with a six digit code sent to your email address, so an email address is the only identifier the site needs and the only one it has. The second is that the problems and solutions are the product, so almost everything stored about you is a record of your own work on them, kept so that it is still there when you come back on a different device.

3. What we collect, and why

3.1 Your email address, and signing in

When you make an account we store your email address. We use it to send you the six digit code that signs you in, to send you a receipt when you buy something, and to answer you when you write to us. We never store a password because there is no password to store.

You can also choose to sign in with Google instead of typing a code. If you do, Google tells us your email address and confirms it is yours, and that is what we keep. We do not receive your Google password, we do not get access to your Gmail, your contacts or your files, and we ask for nothing beyond your address. Signing in this way lands you on the same account a code would, so nothing about what we hold changes. You can go back to codes at any time, and using Google is never required.

We keep a record of each time a sign in code is requested for an address, and a record of each successful sign in. The first exists so that nobody can use the sign in form to send mail to a stranger or to burn through a real customer's daily limit of code emails. The second exists so you and we can tell whether an account is being used by somebody who should not have it.

3.2 Your test date, and any score you tell us

If you give us the date of the test you are studying for, we store it and use it to show you how long you have and to pace what we suggest next. It is optional and you can clear it. If you choose to tell us a score after a test, we store that too, and it is used to show you your own history. Neither is shared with anybody and neither is required to use the product.

3.3 Your work on the problems

Every answer you submit is stored: what you typed or which option you chose, whether it was right, how many nudges were open at the time, and when you submitted it. That record is what draws the progress on your problem grid, what lets you see what you answered last time, and what tells us which problems are defeating people so we can write better help for them.

It is kept as a log rather than as a score. Pressing Clear on a problem resets what the page shows you and stops those attempts counting toward your progress, and it does not erase them, because the log is also how a refund is worked out and how we find a problem whose answer key is wrong. Deleting your account deletes all of it, which is described in section 9.

3.4 Nudges, Build Ups and worked solutions

We record when you reveal a worked solution, along with whether you had already answered correctly, how many nudges were open, and how many attempts you had made first. We record your answers to the Build Up questions in the same way we record your answers to the problems.

This is used for two things and nothing else: showing you where you were when you come back, and telling us which explanations are not working. A problem where everybody opens the solution without answering is a problem whose nudges have failed, and that is invisible in the answer log alone.

3.5 Your notes and flags

Notes you write on a problem, and problems you flag to come back to, are stored against your account so they are there on your other devices. They are yours. We do not read them for any purpose other than answering you if you ask us to look at something, and they are never shown to anybody else, with one exception described in the next section.

3.6 Your pencil, and how the site looks

Your pencil's appearance is stored as a handful of words on one row: the color of the barrel, the eraser, what it is standing on, and so on. If you have never edited it, the one you see is generated from your account identifier rather than stored, so it is the same every time without us having written anything down.

Whether you have chosen light or dark, and whether the problem outline is folded away, are stored in cookies on your own device and, once you have an account, on your account so the choice follows you. These are preferences you set, not observations of you.

3.7 Tutors and students

If you are working with a tutor through this site, then the link between the two accounts is stored, along with any assignment they set you and your progress through it. A tutor you are connected to can see how you are doing on the problems they assigned and on the set as a whole: which problems you have attempted, which you got right, and whether you used the Build Ups. That is the entire point of the feature and it is the thing to understand before accepting an invitation.

A tutor cannot see your notes, your flags, or anything you have written to us. A connection can be ended, and ending it stops any further sharing.

3.8 Purchases, and proving you own the book

No card details ever reach this site. Payment is taken by Stripe on their own pages, and what comes back to us is a confirmation, an order reference, the amount, and the email address you gave them. We store that as an order record, and we store what it entitles you to and when that access ends. If you take the book owner credit off Mastery, we store the amount that was credited, so that a receipt or a refund can be worked out later from what actually happened rather than from what the price is today.

If you buy before you have signed in, the entitlement waits against the email address you used at Stripe until an account with that address signs in and claims it.

Verifying a printed copy stores which challenges you were issued, when, and whether each attempt succeeded. We store no part of the answer you typed. The record exists to stop somebody without a copy guessing their way in, and it is the minimum that supports a rate limit.

3.9 Things you send us

If you write to us through the contact form, report a problem with a question, join a waiting list, or sign up as a beta reader, we store what you sent and the email address you sent it from, so that we can reply and so that a report about a wrong answer can be traced back to the question it was about. If you have asked us to email you, we store the fact that we sent it, so you do not get the same thing twice.

3.10 Technical logs, and how visits are counted

Our host keeps ordinary server logs of requests, which include IP addresses, for a short period, in order to serve the site and to defend it from attack. We do not use those logs to build a picture of any individual.

Separately, we count visits ourselves, and we do it without a cookie and without keeping your IP address. Your IP address and browser are combined with a secret that is held only in memory and replaced every day, and only the result of that one way calculation is stored. Two visits from you on the same day can be counted as one person; the same visit tomorrow cannot be matched to today's, and nothing stored can be turned back into an IP address. There is no identifier here that survives the day, which is also why there is nothing in it for us to hand back to you or to delete.

4. What we do not do

We do not sell personal information and we do not share it for advertising. There are no advertising networks, no third party analytics products, no social media pixels, and no cross site tracking on this site. We do not make automated decisions about you that have a legal or similarly significant effect. We do not use what you write in a note or an answer to train anything.

5. Cookies and browser storage

Every cookie this site sets is one of two kinds: the one that keeps you signed in, and the ones that remember a display choice you made, such as light or dark and whether the problem outline is folded away. There are no advertising or analytics cookies here, which is why you have not been asked to consent to any. Blocking the sign in cookie will stop you being able to sign in; blocking the others will lose your preferences and nothing else.

If you are not signed in, the site keeps your answers in your own browser for the length of the visit, so that a refresh does not throw away work that has nowhere else to go. Your progress through a Build Up is kept a little longer, because it is visible on the grid and losing it would look like losing work. None of it is sent to us while you are signed out. Making an account moves your work to your account, and from then on the account is the copy that counts.

6. Who else handles it

We use a small number of services to run this site. Each one is given only what it needs to do its job, and none of them is permitted to use it for their own purposes.

• Supabase stores the database and runs the sign in, so it holds everything in section 3 and sends the six digit codes.
• Stripe takes payments. Card details are given to them and never to us.
• Resend sends our email, so it handles your address and the contents of what we send you.
• Vercel hosts the site and keeps the request logs described in section 3.10.
• Google, only if you choose to sign in with it. They tell us your email address and nothing else, and they know you signed in here.
• Desmos provides the graphing calculator that appears on a problem page. It is loaded from Desmos when you open a problem, so they see the request that loads it. We send them nothing about you, and what you type into the calculator is not sent to us.

We may also disclose information if the law requires it, or to protect the site and its users from fraud or abuse. If the business is ever sold or transferred, records would go with it, and this policy would go with them until you were told otherwise.

7. Where it is stored

The database and the site are hosted in the United States. If you are writing to us from somewhere else, your information is being sent there.

8. How long it is kept

Your account and everything attached to it are kept for as long as the account exists. Deleting the account deletes them, and the database is set up so that they go with it rather than being left behind: your attempts, notes, flags, pencil, test date, Build Up progress, tutor connections and entitlements are all removed with the account.

Two things outlive it deliberately. Paid order records are kept for [to be supplied: how long paid order records are kept, which depends on tax law], because they are tax records. The visit counts described in section 3.10 are kept as counts, and there is nothing in them that identifies anybody.

Access itself expires on its own schedule rather than by deletion: digital access lasts 12 months from purchase, and the worked solutions a verified book owner earns never expire.

9. Your choices, and getting your data deleted

You can see and change most of what we hold from your account page: your test date, your pencil, how the site looks, and your progress. You can clear your progress on any individual problem from the problem itself.

You can ask us to delete your account and its data from your account page, and you do not need a reason. We will tell you exactly what goes and what has to stay before you confirm it. You can also write to support@pencilsdownlabs.com to ask what we hold about you, to ask for a copy of it, to correct it, or to have it deleted, and we will act on that.

Depending on where you live, you may have specific rights of this kind under your own law. We do not ask where you live and we do not intend to answer these requests differently depending on the answer, so you are welcome to make any of them whatever your address is. We will not treat you differently for asking.

If you have asked us to email you about a launch or a newsletter, every one of those emails has a way to stop them, and stopping them does not affect your access or the email we have to send you about a purchase.

10. Children

This is built for students preparing for a college admissions test, so many of the people using it are under 18. Nobody under 13 may make an account, and we do not knowingly collect anything from a child under 13. If we learn that an account belongs to somebody under 13, we will delete it and refund anything paid for it.

If you are under 18, a parent or guardian has to agree to the terms alongside you. A parent or guardian may write to us about a child's account, including to ask what it holds or to have it deleted, and we will act on that request.

11. Security

Who can read what is enforced in the database itself rather than in the website, so a bug in a page cannot hand somebody content or records they have not got. There are no passwords to be stolen. Card details never reach us. The key that can write entitlements exists in one place on the server and is never sent to a browser.

No system is perfectly secure, and we are not promising one is. If something happens that affects you, we will tell you.

12. Changes to this policy

If this changes, the date at the top changes with it. If a change materially affects what we do with something we already hold about you, we will tell you by email rather than relying on you noticing the date.

13. How to reach us

Write to support@pencilsdownlabs.com about anything in this policy, including a request about your own data. Messages reach a person and are answered by email.

Pencils Down Labs is operated by Armaan Singh, a sole proprietor trading as Pencils Down Labs. Our postal address is [to be supplied: the postal mailing address of the operator].