Privacy Policy
Local computation is our architecture, not a slogan — your inputs never leave your device
Last updated: August 2025
Core Principle: Local Computation
The founding idea of YiJianSuan: every calculation runs locally in your browser. Anything you enter (amounts, weight, dates) exists only in your browser memory — it is never sent to any server, never stored in any database, and never seen by anyone (including us). This is not boilerplate but our technical architecture: all logic executes on your device, and the tools keep working even offline.
Data We Do NOT Collect
- Values you type into any calculator, and their results
- Personal identity information such as name, ID number or phone number (we simply have no accounts or sign-up)
- Personal behavioral profiles: browsing trails, click behavior
- Precise geolocation
The Minimal Data We Process
To improve content and keep the service running, the following limited, non-identifying data is processed:
| Scenario | Data | Purpose | Storage |
|---|---|---|---|
| Tool ratings (when you rate) | Rating value (1–5 stars) + tool ID | Aggregate average scores to help you judge tool quality | Supabase (no identity attached) |
| Usage counts | How often a tool is opened (aggregate count) | Learn which tools are most useful and plan content | Supabase (totals only, no individual records) |
| Preference memory | Language choice, install-tip dismissal | Remember your preferences and avoid repeated prompts | Your own browser (Cookie/LocalStorage) |
| Analytics (optional) | Aggregate page-view statistics | Understand overall traffic trends | Third-party analytics platforms (see below) |
Cookie & Local Storage Details
All of the above live in your own browser. You can clear them anytime via browser settings — every calculator keeps working afterwards.
| Name | Purpose | Location | Duration |
|---|---|---|---|
| NEXT_LOCALE | Remembers your manual language choice (中文/English) | Browser cookie | Persistent (clearable anytime) |
| pwa-install-tip-dismissed-at | Remembers you dismissed the "Add to Home Screen" tip for 30 days | Browser LocalStorage | 30 days |
| sw-purged | Prevents refresh loops during cache self-healing | Browser SessionStorage | Current session |
Third-Party Services
- Analytics: if the site owner enables Baidu Tongji / Google Analytics / Microsoft Clarity, only aggregate page-view statistics are collected, governed by their respective privacy policies
- CDN & fonts: static assets (fonts, icons) load via CDNs, which may log access records (IP, user agent)
- PWA cache: the Service Worker caches some pages on your device for offline access; cached content is limited to the pages themselves
- Supabase: used solely to store the anonymous ratings and aggregate usage counts described above
Data Security
The entire site is served over HTTPS. Since we never collect your inputs, there is no calculation data on our servers that could be breached; even if a third party obtained your visit records, they could not know what you entered or what results you received.
Your Rights & Choices
- Clear local data: wipe cookies and site data in your browser settings — effective immediately
- Opt out of analytics: use Do Not Track or an ad blocker — nothing breaks
- Dismiss install prompts: dismissed tips stay hidden for 30 days
- Questions & complaints: reach us via QQ / WeChat on the contact page — answered within 7 business days
Children’s Privacy
We do not collect personal information from children under 14. The site offers general-purpose calculation tools with no child-directed content or social features.
Policy Updates
This policy may be updated as features evolve; the last-updated date is shown at the top of this page, and material changes will be announced prominently on the homepage. Continued use of the site constitutes acceptance of the updated policy.
Contact
For any questions, feedback or complaints about this privacy policy, contact us: QQ 9277493, WeChat 13993092173 (please note "privacy inquiry" when adding). More channels are listed on the contact page.