Privacy Policy
Last updated August 11, 2026
1. Who we are
2Sigma is an exam-preparation service for university students. We decide why and how your personal data is processed, which makes us the controller of that data under the EU General Data Protection Regulation (GDPR) and the database owner under the Israeli Protection of Privacy Law, 5741-1981 as amended by Amendment 13.
2Sigma is run from Israel by an individual trader (osek), not by an incorporated company, so there is no company number to give. That trader is the controller of your data and the owner of the database.
For anything in this policy, including any request about your data, write to [email protected]. We have not appointed a Data Protection Officer; this address reaches the person responsible for privacy.
2. What we collect
Everything below is data we actually hold. Nothing on this list is optional telemetry we could switch off and still run the service, except where marked.
| Category | What it is | Where it comes from |
|---|---|---|
| Account identity | Email address, password (stored only by Firebase, never by us), display name, and a Firebase user ID | You, at sign-up, or your Google account if you sign in with Google |
| Course enrolment | Which courses you are enrolled in and when | Your use of the service |
| Answers | The text you type as an answer, and the flattened PNG of anything you draw on the practice canvas | You, when you submit an answer |
| Evaluations | The score, written feedback and inline comments our AI evaluator produced for each answer | Generated when you submit |
| Mastery scores | A score per topic and per sub-topic, and the questions you have skipped | Derived from your answers |
| Tutor conversations | Your full conversation with Sigmund, our AI tutor, stored per practice session | You, while you practise |
| Credits and payments | Credit packs, the ledger of every credit granted or spent, the price and currency you paid, the tier you bought, and coupon redemptions | Your purchases and redemptions |
| Technical logs | Structured server logs for abuse and cost control, including your IP address on the anonymous landing-page chat | Automatically, on every request |
| Analytics and diagnostics | Product analytics events, error reports, performance traces and error-triggered session recordings | Automatically — subject to your consent, see section 5 |
We do not collect your date of birth, national ID number, address, or payment card details. Card details go directly to PayPal and never reach our servers.
The anonymous chat on our landing page is not stored. The transcript stays in your browser and is sent to our AI provider for each reply; we keep no copy.
3. Why we use it, and our legal basis
| What we do | Why | Legal basis (GDPR Art. 6) |
|---|---|---|
| Create and run your account | To give you the service you asked for | Performance of a contract |
| Serve questions, evaluate answers, run the tutor | The service itself | Performance of a contract |
| Track mastery and pick your next question | The adaptive part of the service | Performance of a contract |
| Take payment, grant and expire credits, issue receipts | To sell you credits | Performance of a contract |
| Keep accounting records of purchases | Israeli tax and bookkeeping rules | Legal obligation |
| Rate-limit, detect abuse, keep the service secure | To stop the service being abused, and to control the cost of AI calls | Legitimate interests |
| Monitor errors and performance | To find and fix faults | Legitimate interests |
| Product analytics and session recording | To understand how the product is used and improve it | Consent |
Where we rely on legitimate interests, we have balanced them against your rights; you can object at any time (section 9).
4. Artificial intelligence
The tutor ("Sigmund"), the answer evaluator and the landing-page questionnaire are all powered by a large language model provided by Anthropic. This means that the questions you are served, the answers you write, the drawings you submit and every message you send the tutor are transmitted to Anthropic so that a reply or a grade can be generated.
AI output can be wrong. Scores, feedback and explanations are not a guarantee of correctness or of any exam result, and no decision with a legal or similarly significant effect on you is made by automated means.
Please do not type personal details about yourself or anyone else into the tutor or the landing-page chat. Nothing in the service requires them.
5. Analytics, error monitoring and session recording
- Google Analytics 4. We send product events (page views, practice events, purchase funnel) tagged with your Firebase user ID and non-identifying user properties such as your interface language, active course and a bucketed credit balance. We never send your email address or name to Google Analytics. Analytics data is exported to Google BigQuery, and that export dataset is located in the United States.
- Sentry. Errors, stack traces and a sample of performance traces. These run on our legitimate interest in keeping the service working, and are not consent-gated. Sentry Session Replay — a replay of a browsing session in which an error occurred — runs only if you allow analytics. Every replay is captured with all text and all form input masked and all media blocked, so a replay of the practice screen does not show what you wrote or drew.
- LaunchDarkly. Feature-flag evaluation receives your Firebase user ID and your email address, which is what lets us switch a feature on for a defined group of accounts rather than for everyone. It also receives your display name.
- Resend. When you buy credits we email you a confirmation of the pack, from [email protected]. Resend receives your email address, your display name if your sign-in provider gave us one, and the content of that message, in order to deliver it. This is a service message we send to perform our agreement with you, not marketing, so it is not part of the analytics choice below and there is nothing to unsubscribe from; we will ask for your consent separately before ever sending you anything else.
How the choice works. On your first visit, nothing in this section runs: no request is made to Google Analytics and no replay is recorded until you decide. The banner offers accept all and reject all next to each other, one click each. Your decision — what you chose and when — is stored in the consent cookie listed in the next section, so that it can be evidenced later. You can change it at any time from Cookie settings in the page footer, or under Privacy in your account settings; a withdrawal takes effect immediately and stops both.
LaunchDarkly is not part of that choice: it decides which version of the product you are shown, so it runs on our legitimate interest and sets no cookies.
6. Cookies
We use a small number of cookies, and that is the whole list.
| Cookie | Set by | What it does | Lifetime |
|---|---|---|---|
__session | Us | Keeps you signed in. Strictly necessary — without it the service cannot tell who you are | 5 days |
NEXT_LOCALE | Us | Remembers whether you chose Hebrew or English | 1 year |
2sigma_consent | Us | Stores the analytics choice you made and when you made it, and keeps the banner from asking again | 12 months |
_ga, _ga_<id> | Google Analytics | Tells visitors and sessions apart for the usage statistics | up to 2 years |
The first three are strictly necessary or set at your own request, so they do not depend on consent — but none of them tracks you across other websites. The Google Analytics cookies are set only after you accept, never before. Sentry sets no cookies; Session Replay keeps its state in the browser tab's session storage.
7. Who else sees your data
We use the following providers. Except where noted, each acts as a processor that may only handle your data on our instructions.
| Provider | What it receives | Role |
|---|---|---|
| Anthropic | Every question, answer, drawing and tutor message | Processor |
| Google (Firebase Authentication) | Email address, display name, user ID | Processor |
| Google (Analytics 4 and BigQuery) | User ID and event parameters | Processor |
| Sentry | Errors, traces and error-triggered session replays | Processor |
| LaunchDarkly | User ID, email address, display name | Processor |
| Resend | Your email address, display name, and the content of your purchase confirmation | Processor |
| Hetzner | Hosting of the application and the entire database | Processor |
| Cloudflare (R2) | Exam and question assets only — no student data | Processor |
| Discord | Operational alerts — no student data | Processor |
| PayPal | Your name, email address and payment details, when you buy credits | Independent controller — PayPal handles your payment under its own privacy policy |
We do not sell your personal data and we do not share it for advertising.
Several of these providers are outside Israel and the European Economic Area, mostly in the United States. Those transfers rely on each provider's own data processing terms and on the Standard Contractual Clauses they incorporate. Transfers into Israel rely on the European Commission's adequacy decision for Israel of 15 January 2024.
8. How long we keep it
We do not run a fixed deletion schedule yet, so what you create stays while your account does. Your account, your answers and drawings, your mastery scores and your tutor conversations are kept for as long as your account is open, and go when you delete it or ask us to — section 9 explains how.
Two things outlive that. Records of what you bought are kept for as long as Israeli tax and bookkeeping rules require, which is why deleting your account does not remove them. Your consent record is kept while we still rely on it, and for a period afterwards, so that we can show what you chose and when.
Technical logs, analytics data and error reports are held by the providers named in sections 5 and 7 under their own retention settings.
We are working on fixed retention periods and will state them here once they are set.
9. Your rights
You have the right to access your data, to have it corrected, to have it erased, to receive a copy in a portable format, to restrict or object to processing, and to withdraw any consent you have given (withdrawal does not affect processing already carried out). Under Israeli law you have the right to review the data we hold about you and to demand its correction or deletion.
Two of these you can exercise yourself, immediately, from your profile menu → Settings: "Download my data" gives you a single JSON file with everything we hold about you, and "Delete my account" erases it. Neither needs our approval and neither waits on us. For anything else — correction, restriction, objection, or withdrawing a consent — email [email protected] and we will respond within 30 days.
Deleting your account erases your record and everything attached to it from our database, your tutor conversations, your Firebase authentication record, and your data held by our analytics and error-monitoring providers. PayPal is an independent controller, so a request about the data PayPal holds has to go to PayPal.
If you think we have handled your data badly, please tell us first. You may also complain to the Israeli Privacy Protection Authority, or — if you are in the EU or the EEA — to the data protection supervisory authority where you live.
10. Security
Access to the production database is limited to the people who need it, staff access to internal tools is logged, and traffic to the service is encrypted in transit. No service is perfectly secure; if a breach affects your data we will notify you and the relevant authority as the law requires.
11. Age
The service is for people aged 18 and over. We do not knowingly collect data from anyone younger. If you believe a minor has an account, write to us and we will delete it.
12. Changes
If we change this policy we will update the date at the top of this page, and we will tell you directly about any change that materially affects your rights.