Privacy & GDPR

The short version

Waterfall runs entirely in your browser. There is no account, no server that sees your answers, and none of your study data is uploaded anywhere. Your exam progress lives in this browser's local storage, on this device, until you export or delete it yourself. The only thing that leaves your browser is an anonymous, cookieless count of which pages were visited — described below.

What is stored, and where

Everything Waterfall keeps is written to your browser's localStorage under keys prefixed wf:v1:. That is:

• Your exam attempts — score, timing, and the answers you gave (up to the most recent 200 per exam; older ones are evicted automatically)
• Per-question review statistics, used to schedule flashcard review
• An in-progress paper, so a refresh does not lose your place
• Preferences — theme, timer sound, partial-credit grading

None of this is sent to a server. If your browser blocks or clears local storage — private browsing, for instance — the app still works for that session, but nothing persists after you close the tab; a banner tells you when this is happening.

Cookies and tracking

Waterfall sets no tracking or advertising cookies, and there is no advertising, no cross-site tracking, no profiling and no session recording. The one notice banner you may see records only that you dismissed it, in local storage, on this device.

There is one piece of analytics: Vercel Web Analytics, which counts page views so the author can see which exams people open. It is cookieless and stores no identifier in your browser — Vercel derives a short-lived, non-reversible hash from request data to estimate daily visitor counts, and keeps aggregate totals only. What it records is the page path, the referring site, and coarse technical facts your browser sends to any website anyway: country, browser, operating system and device type.

What it never sees is the part that matters: your answers, your scores, your review statistics and your in-progress paper are read and written only in this browser's local storage, and no page path contains them. Vercel acts as a data processor for this traffic data; see Vercel's Web Analytics privacy documentation. If a future version adds error reporting or any further analytics, this page and that notice will be updated first.

Your rights (GDPR)

Because your data never leaves your device, most GDPR mechanics are things you already have direct control over in Settings:

• Access & portability — Export snapshot downloads everything as JSON
• Erasure — Reset an exam, or reset everything, deletes it immediately and permanently
• Rectification — since there is no account, there is no record to correct beyond what you control locally

There is no data controller in the GDPR sense for this local data, because nobody but you ever has a copy of it.

Copyright and licensing

Waterfall's code is licensed under the MIT License (LICENSE). Question bank content is licensed separately under Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0; content/LICENSE). Every question is written from primary curriculum documentation — none is copied from a commercial dump site or prep vendor.

Trademarks

Certification names referenced by the question banks — OTCA, CKAD, CKA, KCNA, Terraform Associate, and others — are trademarks of their respective owners, used nominatively to identify which exam a bank prepares for. Waterfall is not affiliated with, endorsed by, or sponsored by The Linux Foundation, CNCF, HashiCorp, Amazon Web Services, or any other certification body.

Questions

Waterfall is an open-source portfolio project. For a question about this policy, open an issue on the project's repository.