Privacy
Privacy policy — local storage, analytics only when configured, and no selling data.
Chemistry Fundamentals is designed to work without accounts or backend databases. Most data stays on your device.
Overview
We keep tracking to a minimum. No account creation is required to read lessons, use calculators, or browse the periodic table. Analytics and ads are only active when explicitly configured — and this deployment shows their status in the footer.
Local data on your device
Some features remember your choices on this device using your browser's storage (localStorage). This is not synced to a server or account.
- What is stored: theme (light/dark/system), saved bookmarks (ID and URL), recently viewed pages (last 20), lesson completion and quiz attempts, calculator history (only if non-sensitive and useful), dismissed help messages, and recent searches (last 20 — shown as 6 chips).
- Why it is stored: to remember your place, keep your saved items, and show recent learning without a login.
- Where it is stored: on this device only, under the key
cf:state:v2. Nothing is uploaded. - How to control it: visit Saved for export and reset, History to clear recent views, or use your browser’s “Clear site data.” You can export a human-readable JSON file (with schema version and export date) before resetting. Separate resets exist for saved items, progress, search history, and all local data. Deletion cannot be undone on this device.
- Clearing browser data may remove local data. It is not restored without an import.
- We do not store form messages, contact details, precise behavioral analytics, or hidden identifiers. Exported files are never automatically uploaded.
Stored only if your browser allows localStorage. If storage is unavailable (private mode or quota), features fall back to defaults without crashing.
Cookies
This site sets no nonessential cookies by default. Essential preference storage (like theme) uses localStorage, not cookies. If analytics or other cookies are added later, the Cookies page and consent wording will be updated and a banner will only appear when nonessential cookies are present. See Cookies for the current statement.
Analytics, third parties, and hosting
Analytics / ads: None is loaded by default. When ENABLE_ANALYTICS or ENABLE_ADS is turned on in deployment, this section and the Cookies page will describe provider, purpose, retention, and consent before any nonessential storage is set. Without explicit authorization no trackers, session replay, or fingerprinting is added.
Hosting / CDN logs: Like most static hosts, our deployment provider (e.g., Cloudflare Pages / Netlify / Vercel) may retain standard access logs (IP, user-agent, requested path, time, referer, status) for security and reliability. We do not augment these logs and do not collect precise behavioral profiles. Refer to your host’s privacy documentation for log retention.
External services: Search Web calls GET /api/web-search only when you use the Search Web tab — proxied to Google Custom Search JSON API via server-held keys (never exposed in the client bundle). The KaTeX stylesheet is fetched from cdn.jsdelivr.net for equation rendering; no chemistry data is sent to the CDN. External links (e.g., IUPAC, NIST, PubChem) open in a new tab with rel="noopener noreferrer" and are governed by the target site’s policy.
Forms / contact: The footer newsletter form is a non-submitting draft until a provider is configured — it shows “Coming soon” and does not send email addresses. If a contact/correction endpoint is added later, collection will be minimal (email + message), transmitted over HTTPS, validated server-side, rate-limited, and disclosed here with processor and retention.
Data retention: localStorage items persist until you reset them atSaved or clear site data in your browser. No server copy exists; clearing cannot be undone. Hosting logs are ephemeral per provider. Exported JSON files you download are under your control and never uploaded automatically.
Age and education
Chemistry Fundamentals is usable by students, including those in high-school courses. We do not knowingly collect personal data from children, we require no account, and we do not show age-gated advertising by default. Teachers and guardians should review local requirements for classroom use and supervise lab activities via Safety and Lab Safety.
Your choices
- Export your local data at Saved before any reset.
- Reset sections individually (saved, recent searches, history, lesson/quiz progress, calculator history) or reset all — see Saved.
- Block or clear site data via browser settings; the site remains readable without JavaScript or storage.
Details
All statements match actual behavior as deployed. For questions, see Contact. Last updated: 2026-08-23.