Scope of this policy
This policy covers TenYears (拾年) backtesting website and its export and sharing features. It describes the application's current practices. Hosting platforms, market-data providers, and third-party websites you choose to visit have their own privacy policies.
The tool does not ask you to connect a brokerage account, provide banking details, or upload real holdings, and it does not open financial accounts. A hosted version may require platform authentication to verify access.
Backtest inputs and market requests
Contribution amounts, dates, frequency, dividend settings, and backtest calculations are processed in your browser. The application has no user database for complete investment plans or results and does not write them to cookies or local storage.
To load prices, your browser sends the selected stock or ETF ticker to this site. The server requests historical market data from Yahoo Finance, or the application uses a saved dataset. The history API does not send your contribution amount, chosen backtest period, or complete results. API failure logs may include the ticker and error reason.
Cookies and local storage
The application uses browser local storage to remember your privacy choice and, only with your permission, your language preference. These two items do not contain contribution amounts, holdings, or backtest returns.
| Record | Purpose and control |
|---|---|
ledger-cookie-choice-v1 | Necessary: remembers Necessary only or Allow language preference. |
ledger-language | Optional: saves Chinese or English only when allowed; removed when permission is withdrawn. |
These local records have no application-defined expiration and remain until you clear this site's browser data or your browser removes them. Choosing Necessary only deletes the saved language preference. Clearing all browser data for this site also deletes the privacy choice. Either choice allows backtesting, downloads, and sharing.
You can change your choice through Cookie settings in the calculator footer. The hosting platform manages its own authentication and security cookies; this site's language-preference setting does not control them.
Backtest links, QR codes, and downloads
A backtest link stores tickers, dates, amount, frequency, dividend settings, language, and chart range after the # symbol. That fragment is not sent to this site's server in ordinary page requests, but it is not encrypted. Anyone holding the link, QR code, or exported file can read these settings.
Links may remain in browser history, bookmarks, browser-sync records, and recipients' devices. Images, PDFs, SVGs, CSVs, and QR codes are generated in your browser. The application does not upload exports to its own file server. Once saved, their retention and sharing depend on you, your device, and any cloud-sync services you use.
Share only settings you are comfortable disclosing. Do not add account numbers, identity information, or other sensitive details to links or captions. Deleting your local file cannot recall copies already saved by other people.
Hosting, fonts, and other services
The site includes no advertising or advertising-tracking integrations. A Cloudflare-hosted version may enable Cloudflare Web Analytics to measure page views, browser and device categories, referrers, and page performance. The host manages these analytics; the language-preference setting does not control them. Hosting services may still process IP addresses, browser information, request times, access paths, and server logs to deliver pages, market data, access security, and troubleshooting. The host may be OpenAI Sites or Cloudflare Pages. Log retention depends on the relevant service's configuration and policies.
This site loads fonts from Google Fonts. Your browser makes requests directly to Google's font domains, allowing that service to receive your IP address and request information. The language-preference setting does not block font requests. Visiting Yahoo Finance or another external link also sends information about that visit to the destination.
Company and fund-issuer logos are provided by Elbstream. Your browser requests each ticker's image directly from its service, which may receive the ticker, IP address, and browser request information. The site does not send contribution amounts, backtest dates, or returns to that service, and image requests omit the page referrer. The language-preference setting does not control these image requests.
These services may process information outside your region. Consult the service policies applicable to the version you visit and your location. The application does not promise a particular retention period for third-party records.
Your choices and privacy requests
You can decline language storage, clear this site's browser data, stop sharing links, and manage your downloaded files. Do not submit real account details through backtest inputs. Raise application-specific privacy questions with the site operator. Requests about platform accounts, platform cookies, or records they retain should be directed to the relevant provider.
Depending on applicable law, you may have rights to access, correct, delete, restrict, or object to processing, or complain to your local regulator. Requests should be handled by the party that holds or processes the information. The scope and exceptions depend on the laws that apply to you.
Security and children's use
Public deployments should be accessed over HTTPS. The application is not directed specifically at children and does not request birth dates or other children's information. Hosting-platform account and age requirements still apply. No transmission, browser storage, or third-party sharing can be guaranteed completely secure; manage your device and sharing audience carefully.
Policy updates
This policy may be updated when processing practices or services change, with the update date shown on this page. New optional local preferences or other processing that requires your choice should be explained and offered before activation. The English and Chinese versions describe the same policy without a blanket language-precedence rule.
Sharing with third-party platforms
Opening a pre-filled sharing window for Weibo, X, Facebook, Reddit, Mastodon, or Bluesky may send your caption and complete backtest link to that platform before you confirm a post. System sharing hands information to your device's sharing feature and selected destination. Images for Instagram are uploaded by you.
The application does not collect social-account tokens or post automatically on your behalf. Third parties process accounts, links, images, and access records under their own policies. Sharing a link does not change this site's access permissions.