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Privacy Policy

Last updated: 5 May 2026

The short version

HanziFluency does not run a backend. Your study progress, settings, decks, and review history are stored in your browser's local storage on the device you use the site from. We do not collect, transmit, or sell that data. A small number of third-party services are used to deliver the site itself (fonts, character stroke data, and — when enabled — advertising); those are detailed below.

What we store on your device

The site uses your browser's localStorage and sessionStorage APIs to persist:

  • Your settings (theme, preferred speech voice, daily goal, audio preferences).
  • Spaced-repetition records: which characters you have reviewed, when, and how often you got them right or wrong.
  • Decks you create or import.
  • Session statistics (drill counts, streaks, completion times).
  • Onboarding and install-prompt state (so the tour does not reappear).

This data never leaves your device. Clearing your browser storage for this site removes it permanently — there is no server-side copy to recover from. You can clear it through your browser settings, or by using the data-management controls in the in-app Settings page.

The site also installs a service worker that caches the app shell and a small amount of static study data so the site works offline once loaded. The service-worker cache is stored on your device, holds no personal data, and can be cleared alongside the rest of your local storage from your browser's site-data controls.

The legal basis for this device-side storage under the UK GDPR and EU GDPR is performance of the service you have requested by visiting the site (Article 6(1)(b)). The storage is also strictly necessary for the functioning of the study tool, and so falls within the “strictly necessary” exemption under PECR Regulation 6(4) and equivalent EU rules — no consent banner is required for it. The AdSense advertising cookies disclosed further down are a separate matter and remain subject to the consent requirements applicable in your jurisdiction.

What we do not collect

  • We do not require an account, email address, or any personally identifying information to use the site.
  • We do not run server-side analytics, session recording, or behavioural tracking.
  • We do not transmit your study progress, decks, or review history to any server we control.
  • We do not sell or share your data with third parties for marketing.

Third-party services

Loading the site involves requests to a small number of third parties. These providers may receive your IP address and basic request metadata as a normal part of how the web works.

Hosting and content delivery

The site is served as static files from a content delivery network. The hosting provider may keep short-lived request logs (IP address, user agent, requested path, timestamp) for operational purposes such as abuse prevention and uptime monitoring.

Google Fonts

Chinese typography (Noto Sans SC, Noto Serif SC, Ma Shan Zheng) is served from fonts.googleapis.com and fonts.gstatic.com. Google may receive your IP address as part of font delivery. Google's privacy policy is at policies.google.com/privacy.

jsDelivr (stroke-order data)

Animated stroke-order diagrams are loaded from cdn.jsdelivr.net, a public open-source content delivery network. jsDelivr does not set cookies and processes only the request metadata required to serve the file.

Browser speech synthesis

Audio playback uses your browser's built-in SpeechSynthesis API. Whether the synthesised audio is generated locally on your device or via your operating system's cloud voice service depends on the voice you select and your browser; consult your browser and operating system documentation for details.

Advertising — Google AdSense

HanziFluency may display advertising provided by Google AdSense. When advertising is enabled, Google and its third-party vendors use cookies (including the DART cookie) to serve ads based on your prior visits to this site and other sites on the internet. You can opt out of personalised advertising by visiting Google Ads Settings, and you can opt out of third-party vendor cookies via the Digital Advertising Alliance or Your Online Choices (EU).

Cookies

The site itself does not set first-party cookies. Where third-party services are loaded (see above), those services may set cookies under their own privacy policies. If you are visiting from the European Economic Area, the United Kingdom, or another region that requires consent for non-essential cookies, a consent banner will be shown before any non-essential cookies are stored.

Children

HanziFluency is not directed at children under the age of 13. If you believe a child has provided personal information to us through this site, please contact us so we can remove it — although in practice the site has no mechanism to receive personal information.

Your rights

Depending on your jurisdiction, you may have the right to access, correct, delete, or export the personal data a service holds about you, and to object to certain processing. Because HanziFluency stores your data only in your own browser, you can exercise most of these rights directly:

  • Access / export: the in-app deck and progress views show all the data we hold; deck export is available from the Decks page.
  • Delete: clear browser storage for this site, or use the “reset” controls in Settings.
  • Object / restrict processing: stop using the site; nothing is retained server-side.

For requests relating to data held by third parties listed above, contact those providers directly. For anything else, see the contact details below.

Changes to this policy

Material changes to this policy will be reflected by an updated date at the top of the page. We recommend reviewing the policy periodically.

Contact

Questions about this policy can be sent to [email protected], or via the contact page.