Privacy Policy
Last updated 25 September 2026
λ master is a free interview practice site run by Lambda Master("we", "us"). We are the controller of the personal data described here. You can use every quiz without an account, and we try to collect as little as the site needs to work.
What we collect
Quiz activity
When you take a quiz we store the questions you were given, the answers you chose and your score. This is not linked to your name or email, because we don't ask for either. Your browser tab keeps the ID of the quiz in progress so that a page refresh doesn't lose it.
Reports and feedback
If you report a question or send feedback, we store what you submit: the reason or category, any rating, and the text you type. Please don't put personal information in these messages.
Request data
Our servers see your IP address on every request. We use it to apply rate limits that protect the site from abuse. To understand how quizzes are used we also record when you start and finish a quiz (its settings and your score) against a pseudonymous ID derived from your IP address with a secret key. Your IP address itself is never sent to our analytics provider.
Browser analytics (only if you allow it)
With your permission we use PostHog to understand how the site is used: pages viewed, clicks, when you leave a page, and your browser and device type. PostHog then sets a cookie and local storage to recognise return visits. Until you choose "Accept", none of this runs and nothing is stored for analytics. If your browser sends a Global Privacy Control signal, we treat it as a refusal.
You can change your choice at any time. Declining also stops the quiz metrics described above for your visits.
Cookies and browser storage
| Name | Type | Purpose | Needs consent |
|---|---|---|---|
lm_analytics_consent | Local storage | Remembers your analytics choice. | No, strictly necessary |
lm_attempt | Session storage, cleared when the tab closes | Resumes a quiz after a page refresh. | No, strictly necessary |
ph_* | Cookie and local storage | PostHog analytics, as described above. | Yes, set only after you accept |
Why we use it (legal bases)
- Running the quizzes, reports and feedback: our legitimate interest in providing the service you asked to use and fixing its content.
- Rate limiting and quiz metrics: our legitimate interest in keeping the site secure, available and working. You can object by declining analytics.
- Browser analytics: your consent, which you can withdraw at any time above.
Who we share it with
We don't sell your personal data or share it for advertising. We use service providers who process it on our behalf under contract: our hosting and database providers, and PostHog, Inc. for analytics. PostHog processes data in the United States. Where data leaves the UK or EEA, we rely on safeguards such as the European Commission's Standard Contractual Clauses.
How long we keep it
- Unfinished quizzes are deleted after 7 days. Completed quizzes are kept so the results stay available.
- Reports and feedback are kept until we have dealt with them and no longer need them.
- Analytics events are kept for as long as our PostHog plan retains them.
Your rights
Depending on where you live, you may have the right to access, correct or delete your personal data, to restrict or object to how we use it, to receive a copy of it, and to withdraw consent. To make a request, email hello@lambdamaster.app. Because we don't know who you are, we may need details that let us find your data, such as the approximate time you took a quiz. You also have the right to complain to your local data protection authority.
Children
λ master is meant for people preparing for software engineering jobs. It is not aimed at children under 16, and we don't knowingly collect their data.
Changes to this policy
If we change how we handle personal data, we will update this page and the date above. If a change needs your consent, we will ask for it again.
Contact
Lambda Master · hello@lambdamaster.app
See also our Terms of Service.