Last updated: October 24, 2026
StemPy Lab ("we", "the site") is an educational platform for learning science and mathematics through conceptual explanations, problems, quizzes, and Python-based exercises, built and maintained by senLearn, a sole proprietorship owned by Smt. Purnima Sen, based in West Bengal, India. This page explains what information we collect, why, and how it's handled.
Account information. When you sign up, we collect your name, email address, and password (handled entirely by our authentication provider, Supabase, so we never see or store your password ourselves), and your date of birth. If you are 18 or over we use the date only to confirm that, and do not keep it. If you are under 18 we keep it, together with your parent or guardian's email address, until you turn 18 (see "Users under 18" below). Adults may optionally add a profile photo. Every account is given a member ID (for example SP-48K7QX) that never changes, so people with the same name can be told apart. If you choose, you can also give the full name to print on your certificates; it is kept apart from your profile.
Content you create. Problems, quizzes, labs, mock tests, question sets, courses, resources, notes, discussion posts, comments, and any images or files you upload are stored against your account so they can be attributed to you and shown to other users.
Teacher applications. If you apply to teach, we keep what you tell us (where and what you teach, your qualification and role, years of teaching, and, if you give them, a phone number and a link) with your account. Only StemPy Lab's administrators see it, to decide on your application and to contact you about it. When you are approved, your qualification, role and workplace fill your teacher profile, where you can change them.
Requests for new exams. If you tell us which exam you are preparing for (Don't find your exam? on the Mock Tests page), we keep your answer with your account. Only StemPy Lab's administrators see it, as totals and recent requests, to decide which series and subjects to add.
Survey after an exam. After you take an open exam, you may answer a few questions about it (your class, how much of the syllabus you have studied, how the paper felt, the time, and what you would like next). Your answers are kept with your account so that you can change them and so that your class is filled in next time. The exam's organiser and StemPy Lab's administrators see only totals and comments, never your name. Once at least 10 have answered, a few totals may be shown on the exam's and the series' pages (for example "71% found it challenging"). Answering is up to you.
Declarations about tests. When a teacher publishes a test or sends an exam for approval, they declare that they have reviewed its questions and answers. We record the declaration with the date and time, their account, name and email, the IP address and browser it was made from, and a copy of the paper as it stood. These records are kept after the test or the account is deleted, because they exist to settle disputes about a paper; the teacher can view and download their own, and StemPy Lab's administrators can see all of them.
Activity and progress data. We track which concepts, problems, quizzes, and labs you've engaged with, your quiz/test scores, and the code and output from Python Labs you run, so we can show your progress, certificates, and leaderboard standing. Code in Python Labs runs entirely in your own browser (via Pyodide). It is never executed on our servers, but the code and its output are saved to your account when you run it, so your work can be reviewed later.
Timed tests and exams. While you take a timed test or an exam we record how long each question is on screen (when its author has kept this on), and how often and for how long you leave the exam screen. You see your own times in your review. Your teacher or the exam's organiser sees them, to judge how the test went and whether its rules were kept: an attempt that leaves the screen more often than the exam allows is held out of the ranks and certificates until they review it, and they can clear it or disqualify it. If you appeal such a decision, the reason you write is seen by them and by StemPy Lab's administrators, and kept with your attempt.
Registering for an exam. You may give your school and city when you register: the exam's organiser sees them, with your name, member ID and result, and gets them in the list of candidates. An adult may also choose to share their email address with the organiser; an under-18's email, and their parent's, are never shared. A phone number given for problems on the exam day (a parent's, for an under-18) is seen only by you and StemPy Lab's administrators, never by the organiser. An organiser can write to an exam's candidates (and the parents of under-18 candidates) only through StemPy Lab, without seeing any address; each message is kept, and may be checked. In StemPy Lab's live series we keep your place, percentile and points for each sitting; the series' standings and the site's leaderboard show your name (a first name only for under-18s), member ID and points, and a monthly champion's trophy shows on their profile. The exams you say you are preparing for are kept with your account, to put them first for you. For an exam with a fee, you pay its organiser directly: StemPy Lab never asks for or receives card, bank or UPI details for it. If you tell the organiser you have paid, they see what you give (how you paid, the payment's reference, the payer's name and your note) with your name and member ID, so they can find the payment; it is kept with the exam. An access code you use is linked to your account, and the organiser sees who used it. An exam's name, host, date, length and announcements are public: they show on its page, on the Mock Tests page, in link previews, and in the calendar and feeds that other websites may show; who registered for it, and the results, never are. A teacher may also show a class that takes join requests on the Mock Tests page: its name, description, subject, level, teacher or institute, and how many students and class tests it has (never who the students are). A QR code on the site or on a poster holds only the address of the page it opens. Tests held in a class or as an exam may be listed on the Mock Tests page once they end, showing who held them, the subject, level, date and how many took part: never the paper, scores or names.
Reading and use of pages. On lessons, problems, quizzes, labs, courses, mock tests, notes and blog posts we count how many times a page is opened and for how long it is open and in use (time with the tab idle or hidden is not counted). If you are signed in, this is saved against your account so we can see what helps people learn and which content to improve. Teachers see only totals for their own content, never who a person is, except for students in their own classes. If you are not signed in, a random code stored in your browser lets us count a visit once, without your name. Nothing is counted if your browser sends a "Do Not Track" signal. We do not use this for advertising and we do not share it with anyone.
Class and teacher-student data. If you join or teach a class, we store class membership, assignments, teacher feedback, and assessment results tied to that class. A teacher may invite another teacher to co-teach a class or co-author a course: accepted collaborators can see and manage the same class/course data as the original teacher.
Content feedback and ratings. Students can rate and leave feedback on classes, courses, problems, quizzes, and labs. By default this is anonymous: the teacher or author sees the rating and comment but never who submitted it; only you can see your own feedback tied to your name. You can optionally choose to post feedback under your own name instead, per submission.
Role changes. If a site administrator changes an account's role (for example, promoting a teacher to moderator or admin), that change is logged with who made it and when. This log is visible only to superadmins, for accountability.
Communications. We send a welcome email when you join, and emails about your account itself (for example a change to your role, or the result of a teacher application); these are sent whatever your settings are. If you enable email notifications in your profile, we also send emails for time-sensitive events and decisions (live class sessions, certificates, approvals, reports and moderation outcomes), and about your tests: an exam's announcements and its organiser's messages, results, appeals, reminders, class announcements and new class tests (several at once come as one email). Every email links to the Terms of Use, this policy, the Refund Policy and Help. We use our email provider, Resend. You can turn the optional emails off any time from your profile settings. For a learner under 18 we also email their parent or guardian to ask for approval, and to confirm what they decided.
Records of emails and approvals. We keep a record of the emails the site sends (the address, the subject and text, the time, and the email provider's message reference) and of every parent or guardian approval or refusal (the time, the address that responded, the network address and browser details of the response, and which versions of the Terms of Use and this policy were agreed to). These records are visible only to superadmins and are kept so we can show what was sent and decided, and to resolve any dispute.
Live classes. When a teacher starts a live session, we record when it started and ended, and which students joined and when (attendance), so the teacher can see who attended. The video call itself runs on Jitsi (meet.jit.si, operated by 8x8, Inc.) or, if the teacher chooses, on a meeting link the teacher provides (for example Google Meet or Zoom). Those services see your name and your audio and video if you turn them on, under their own privacy policies. A teacher who records a session must show the class a recording notice, and the recording is then held by the teacher and the service they used, not by us.
Technical data. Like any website, our servers and our hosting and security providers handle your IP address and browser details when you visit. We use them to keep the site secure and to limit abuse, and to work out your country so we can show the right price (Indian rupees in India, US dollars elsewhere). We do not use them to build a profile of you. For a parent's approval we also keep the network address of the response, as described above.
To operate the site: authenticating you, showing your content and progress, enabling teacher-student interaction within classes, sending notifications you've opted into, and maintaining leaderboards and public profiles. We do not sell your personal information, and we do not use it for advertising.
We use a small number of third-party service providers to run the site:
We pay these providers to run the site for us. We do not sell your information to anyone, and we share it with a public authority only when the law requires it.
Some pages link out to third-party educational resources (for example, PhET Interactive Simulations). Visiting those links is subject to that third party's own privacy policy, not ours.
Our database and files are held by Supabase in Japan (Tokyo), and the website is served from Vercel in the same region. Our email provider, our AI provider, and some of the services above are based in the United States. By using the site you understand that your information is processed outside India. We do this only with providers that protect it with security measures, and we do not send it to any country the Government of India has restricted for this purpose.
How long we keep it. We keep your account and content until you ask us to delete them. Records of emails and of parent approvals are kept for two years and then deleted; the latest parent decision for a living account is kept for as long as it is in force. A date of birth and guardian details are deleted when you turn 18. Error reports are deleted once the problem is fixed. Payment records are kept for as long as accounting and tax law require. After you delete your account, copies in our backups disappear when the backups are replaced.
If something goes wrong. If a security breach affects your personal data, we will tell you and the authorities in the way and the time the law requires.
Your name, profile photo (adults only), and public profile (badges, leaderboard standing, published content) are visible to other signed-in users; a learner's profile page is not shown to people who aren't signed in and is kept out of search engines. Your email address is not shown publicly. Content you post in community areas (discussions, comments, problems, quizzes, labs, mock tests, question sets, courses, resources, and notes not locked private by their author) is visible to anyone who can access that section. Content feedback and ratings you submit are shown to the relevant teacher/author without your identity, unless you chose to post under your own name for that submission.
Your performance. The My performance page (your scores over time, your strong and weak topics, and the rough guide to where your average would stand in a real exam) is worked out from your own results whenever you open it, and only you see it. The Leaderboard's Most Improved list shows your name and how many points your average rose, the same way the other leaderboard lists show names.
Certificates. A certificate you earn (for an exam, a learning path or a class) shows your full name (the name you gave for certificates, or else your profile name), your member ID, what it is for, and, for an exam, your marks and place. Each certificate has a number and a QR code, and anyone who has them can open the certificate on the site to check it is genuine. Certificates are not listed anywhere and are kept out of search engines, so a certificate is seen only by the people you show it to. Your teachers and an exam's organiser see your member ID beside your name, and other candidates see it beside your name in an exam's ranks.
Content drafting. Admins, and specific teacher accounts an admin has approved, can use AI to help draft problems, quizzes, labs, courses, and notes. Anything AI-drafted lands in the same editable draft form as manually written content and goes through the same review before it's published. Nothing is auto-published from AI output.
Practice generator. Accounts an admin has enabled it forcan generate an AI-written practice problem for their own study use.
Translation. Any logged-in user can request an AI-generated translation of content into another language.
Exam figures. Admins can ask AI to look up an exam's published score-to-percentile or score-to-rank figures on the web. Only the exam's name and year (and an admin's note on what to look for) are sent; nothing about any student is. An admin checks the figures against their sources before students see them.
Each of these sends the relevant request content (for example, the topic/grade/category you specify, or the text being translated) to our AI provider, Anthropic (the Claude API), to generate a response. We don't send your name, email, or other account information as part of these requests. Requests are rate-limited per account, and these features may be restricted or disabled site-wide at our discretion.
We use a session cookie set by Supabase to keep you signed in, and your browser's local storage for things like your light or dark theme, unfinished drafts, and which of your badges your dashboard has already shown you. A small cookie remembers whether to show the exams for India or for elsewhere (set from your browser's time zone or your profile's country); it holds nothing else. We do not use advertising or tracking cookies of our own. Some pages embed a video or a simulation from another service (YouTube, Vimeo, PhET, Desmos, GeoGebra); that service may set its own cookies when you play or open it, and its own privacy policy applies to that.
To see how the site is used and how fast it loads, we use Vercel Web Analytics and Vercel Speed Insights. They count page visits and measure page speed without cookies and without identifying you or building a profile of you.
When a page breaks, your browser sends us a short error report: what went wrong, which page it was on (without anything after a "?" in the address) and the type of browser. It isn't linked to your account, and we use it only to fix problems.
Many of our users are school students, and we treat anyone under 18 with extra care:
We do not show advertising to anyone, and we do not track or monitor the behaviour of children to target them with anything. A parent or guardian can ask us to review or delete their child's data at any time using the contact details below. The age at which someone can consent to data processing on their own varies by country, and a date of birth entered at sign-up is self-declared. The Digital Personal Data Protection Act, 2023 treats anyone under 18 as a child and will require a parent's verifiable consent before a child's data is processed; its main duties start on 13 May 2027, and we are preparing for them.
You can edit or delete most of your own content directly from the site. You can update or remove your profile information from your profile settings.
You can also ask us, at support@stempylab.com, to give you a summary of the personal data we hold about you and who we share it with, to correct data that is wrong or incomplete, to erase your data and delete your account, or to stop using your data for a purpose you agreed to (you can withdraw consent as easily as you gave it, for example by turning off optional emails). You can also name another person to exercise these rights for you if you die or cannot act. We reply within 15 days. If you are not satisfied with our reply, write to the Grievance Officer below. Once the Data Protection Board of India is taking complaints, you can also complain to it. Where you live outside India, you may have further rights under your own country's law; write to us and we will answer.
The laws behind this page are the Information Technology Act, 2000 (section 43A) and the Reasonable Security Practices Rules, 2011 made under it, which apply today, and the Digital Personal Data Protection Act, 2023 and Rules, 2025, whose main duties start on 13 May 2027. We follow reasonable security practices: your data is encrypted in transit, access inside the site is controlled by role, and the people who can reach the database are limited.
This policy is governed by the laws of India, without regard to conflict-of-law principles. Any dispute arising from this policy or how we handle your data is subject to the exclusive jurisdiction of the courts at Arambagh, District Hooghly, West Bengal (and, where the value or nature of a claim requires, the District Court at Chinsurah, Hooghly), and the Calcutta High Court on appeal.
Under the Information Technology Act, 2000 and the Information Technology (Intermediary Guidelines and Digital Media Ethics Code) Rules, 2021, our designated Grievance Officer for privacy and data-related complaints is:
Name: Arghya Sen (Grievance Officer, appointed by senLearn)
Address: senLearn (sole proprietorship of Smt. Purnima Sen, Proprietor)
Village Senpur, Post Office Nangulpara
District Hooghly, West Bengal, PIN 712406, India
Email: support@stempylab.com
We acknowledge a complaint within 24 hours and resolve it within 15 days.
If we materially change what we collect or how we use it, we'll update this page and post a site announcement, and we remind our users of our policies at least once a year.
Questions about this policy? Contact us at support@stempylab.com.
Our address:
senLearn (sole proprietorship of Smt. Purnima Sen, Proprietor)
Village Senpur, Post Office Nangulpara
District Hooghly, West Bengal, PIN 712406, India