Privacy Policy

Last updated October 18, 2026. See also the Terms of Service.

This Privacy Policy explains what information https://sysdesignprep.com (the "Site") collects, how it is used, and the choices you have. We keep it short because we collect little.

1. What we collect

Without an account. The Site works without signing in. Where you are in a walkthrough is kept in your browser's local storage so you can pick up where you left off.

With an account. When you sign in with Google we receive your name, email address and profile picture from Google, and we create a profile record. We do not receive your Google password. Once signed in, how far you have watched each walkthrough is stored against your account so it follows you across devices.

When you buy Pro. Checkout is handled by Stripe. Stripe collects your payment details, billing address and, if you provide one, tax id. We receive your Stripe customer id, the plan you bought, its status and renewal date, and the billing country needed for tax. We never see or store full card numbers.

When you use the AI features. The AI interviewer and answer grading send what you type to a third-party model provider (currently OpenAI) so it can reply or grade it. We store the resulting transcript (your answers, the interviewer's questions and the debrief) against your account, so you can look back at a round, and we record the token count and cost of each call so we can keep the service running. Do not type anything into an interview you would not want stored: it is an answer to a practice question, not a place for confidential information. The provider is bound by its own terms and, under our agreement with it, does not use the content to train its models.

What you do on the Site. To understand how the Site is used and to improve it, we record your activity with a timestamp and where you were at the time: the pages and questions you open, how far you go through a walkthrough, what you draw on the whiteboard (as shapes and labels, not screenshots), the questions you ask the AI Mentor and its answers, and each exchange with the AI interviewer together with how far the round had got. Before you sign in this is linked only to a random identifier stored in your browser; when you sign in, that browser's earlier activity is linked to your account. We do not record keystrokes, mouse movements or your screen.

When you report a problem. If you use the "report an issue" form we store the message you write, the page it was sent from, and your email address if you are signed in, so we can fix the problem and reply.

Automatically. Like most sites we receive standard server logs (IP address, browser, pages requested, timestamps) from our hosting provider, and we use Google Analytics to understand which pages are used. Analytics data is aggregated and does not identify you to us.

2. How we use it

to run the Site and keep you signed in;
to run the AI interviewer and answer grading, and to keep the transcripts available to you;
to meter and cap what the AI costs, so the service stays affordable to run;
to sync your progress across devices;
to process payments, manage subscriptions, prevent fraud and comply with tax law;
to answer your support requests;
to understand how the Site is used, individually and in aggregate, and to improve the questions, walkthroughs and AI features.

We do not sell personal information and we do not use it for third-party advertising.

3. Legal bases (EEA and UK)

We process account and payment data to perform our contract with you; server logs, fraud prevention, analytics and activity records under our legitimate interest in running a secure and useful site; and anything else with your consent, which you can withdraw at any time.

Only the service providers that make the Site work, each bound by its own privacy terms and permitted to use the data only to provide the service to us: a hosting provider (request logs), an authentication and database provider (profile, activity records, subscription status), a payment processor (payment and billing details; currently Stripe), a model provider for the AI features (what you type into an interview or a graded answer; currently OpenAI), and an analytics provider (aggregated usage; currently Google Analytics). Sign-in is provided by Google, which shares your account basics with us as described above.

We may also disclose information if the law requires it or to protect the rights and safety of users or the Site.

5. Cookies and local storage

We use local storage for your theme preference, your place in a walkthrough, and a random identifier that groups your activity before you sign in. Our authentication provider sets a cookie or local storage entry to keep you signed in. Google Analytics sets its own cookies; you can block them with a browser extension or by disabling cookies for this site without losing any functionality other than being signed in. We do not use advertising cookies.

6. Retention

Account data is kept while your account exists. Activity records and AI interview transcripts are kept while your account exists so your history stays available; activity that was never linked to an account is deleted after 24 months; you can ask us to delete a transcript, or all of them, at any time. Payment records are kept for as long as tax and accounting law require (typically 7 years). Server logs are kept for a short period by our hosting provider. If you delete your account we delete your profile and activity records within 30 days; payment records are retained as required by law.

7. Your rights

Depending on where you live you may have the right to access, correct, export or delete your personal information, to object to or restrict its processing, and to complain to a data protection authority. To exercise any of these, email us. We will respond within 30 days. Deleting your account can also be requested by email at any time.

8. Security

Data is transmitted over HTTPS and stored with providers that maintain industry-standard security programs. Access to production data is limited to what is needed to operate the Site. No system is perfectly secure; if we learn of a breach affecting your data we will notify you as the law requires.

9. International transfers

Our providers operate in the United States and other countries. Where required, transfers from the EEA or UK rely on standard contractual clauses or an adequacy decision.

10. Children

The Site is not directed at children under 16 and we do not knowingly collect their personal information. If you believe a child has provided us data, contact us and we will delete it.

11. Changes

We may update this policy. The date at the top shows the latest version. Material changes will be announced on the Site.

12. Contact

Privacy questions or requests: support@sysdesignprep.com.