--- title: "Privacy Policy | Sandbox Physics" description: "How Sandbox Physics handles the limited information needed to deliver, protect, and improve the site." canonical_url: "https://sandboxphysics.com/privacy/" language: "en" page_type: "legal" alternate_languages: zh-CN: "https://sandboxphysics.com/zh/privacy/" last_modified: "2026-10-22" --- [Sandbox Physics](https://sandboxphysics.com/) Privacy Policy Utility · Privacy # Privacy Policy How Sandbox Physics handles the limited information needed to deliver, protect, and improve the site. Last updated October 18, 2026 ## At a glance 01 ### No account required You can browse lessons and run experiments without creating an account or submitting a profile. 02 ### No advertising profile Sandbox Physics does not sell personal information or use it for cross-site behavioral advertising. It counts page views and Lab starts in aggregate, without cookies or identifiers. 03 ### Small, functional storage The site stores a language preference on your device and uses a short-lived security cookie when a Lab starts. ## On this browser Your chosen language stays on this device. No account or cloud sync. Clear it here to start fresh; this page stays in its current language. ## Scope This policy applies to sandboxphysics.com and the interactive experiments, articles, search tools, and supporting services delivered through it. It does not control websites reached through external links. ## Information processed Sandbox Physics is designed to work without an account, purchase, or user upload. The site does not ask for your name, email address, payment details, or a public profile. The optional feedback form is the only place where text you type is sent to the site. - Standard request data. Hosting and security infrastructure may process an IP address, user-agent string, requested path, request time, referrer, and related network or security metadata. - Local preferences. A small anonymous profile remembers your chosen language in this browser. This version does not record Lab visits or recommendation feedback. The profile contains no account details or Lab session tokens, and the site does not send it to servers or analytics. - Lab runtime session. Starting an interactive Lab creates an essential, HttpOnly, SameSite=Strict cookie. In production it is also Secure. The signed token is limited to the requested Lab engine, bound to this site and a digest of the browser user agent, and expires after 30 minutes. - Aggregate usage counts. When a page loads or a Lab starts, the site records one count with the page path, page type, site language, the referring site’s host name (not its full address) or, when the browser sends no referrer, a host name given in the link’s utm\_source tag, the country Cloudflare derives from the connection, and whether the browser reports a mobile or desktop device. A Lab start also records its LabId. A count contains no cookie, IP address, user-agent string, or visitor identifier, so separate visits cannot be linked. Browsers that send Global Privacy Control or Do Not Track are not counted. - Machine-readable file counts. When robots.txt, an llms.txt index, or the Markdown copy of a page is fetched, the site records one count with the file path, the country Cloudflare derives from the connection, and the name of the AI crawler or agent family that the request declares (for example ClaudeBot or ChatGPT-User), or a generic category. The user-agent string itself, IP address, and any identifier are not stored. - Feedback you send. If you use the feedback form, the site stores your message, the category you chose, the page path, the LabId when you are on a Lab page, the site language, and whether the browser reports a mobile or desktop device. It does not store your IP address, user-agent string, a cookie, or contact details. Please leave personal details out of the message. - Operational events. The runtime may record limited security and error events, such as a rejected protected-asset request, the requested path, a rejection reason, and a Cloudflare request identifier. ## How information is used - Deliver pages, search results, and interactive Lab code. - Remember the language selected on the current device. - Protect Lab runtime assets from unauthorized bulk access and diagnose abuse. - Maintain reliability, investigate errors, and improve site performance and accessibility. - Count which experiments and articles are used, so improvements go where readers actually are. - Read feedback to fix mistakes and improve experiments and articles. - Comply with applicable law and protect the rights, safety, and integrity of the service and its users. ## Service providers and external resources Cloudflare provides hosting, content delivery, security, operational observability, and storage for aggregate usage counts and feedback. The current site may also request typefaces from Google Fonts and icon code from unpkg. Those providers receive the request information needed to return the resource and process it under their own privacy terms. Sandbox Physics does not sell personal information. Information may be disclosed when required by law, to investigate misuse or security incidents, or in connection with a reorganization of the service, subject to appropriate safeguards. ## Retention and security The Lab runtime cookie expires after 30 minutes. The local profile remains in browser storage until you clear it here, clear site data, or your browser removes it. Aggregate usage counts are kept for three months. Feedback is deleted automatically after 12 months. Operational records are kept only as reasonably necessary for reliability, security, and legal obligations, subject to provider and infrastructure settings. Reasonable technical and organizational safeguards are used, including HTTPS, restrictive cookie attributes, same-origin runtime checks, signed sessions, and limited runtime logging. No internet service can guarantee absolute security. ## Your choices and rights You can change the site language at any time or use “Clear local data” on this page to remove the anonymous profile and any older saved language preference. Clearing site data in your browser also removes them. You can remove the runtime cookie through your browser settings, although an interactive Lab will need to create a new essential session before it can run. To stop usage counting, turn on Global Privacy Control or Do Not Track in your browser. To have a feedback message deleted sooner, contact the site operator with the page and the approximate time you sent it. Depending on where you live, privacy law may give you rights to request access, correction, deletion, restriction, or information about the processing of personal information. Because the service generally has no account identity, enough information may be needed to verify and locate a request without collecting unnecessary new data. ## Children and international visitors Sandbox Physics is an educational resource for a general audience and is not designed to collect personal information from children. If you believe a child has provided personal information to the service, please contact the site operator so it can be reviewed and removed where appropriate. The site and its providers may process request data in countries other than the one where you live. Applicable legal safeguards are used where required. ## Changes to this policy This policy may be updated when the site, its providers, or legal requirements change. The date at the top of the page identifies the latest revision. Material changes will be presented on the site when appropriate. ## Privacy questions For a privacy request or a question about this policy, contact the site operator through the author website. [Visit zichaoyang.com](https://zichaoyang.com/) [Read the Terms of Use](https://sandboxphysics.com/terms/)