Z

Browser Extension

Privacy Policy

Last updated: May 23, 2026 · Extension version: 0.1.0 · Publisher: Zerethon

This policy covers the Zerethon Tools browser extension distributed via the Chrome Web Store and Microsoft Edge Add-ons. The website privacy policy that covers tools.zerethon.com itself is here.

In one sentence

The extension collects no personal data, sends nothing to our servers, and contains no analytics or tracking SDKs.

What the extension stores on your device

  • Recently-used tools — a list of up to 8 tool slugs (e.g. json-formatter), stored in chrome.storage.local. Stays on your device. Not transmitted.
  • Favorite tools — a list of up to 50 tool slugs, stored in chrome.storage.sync. This roams across your signed-in Chrome devices via Google's sync infrastructure; it does not pass through any Zerethon server.

Both lists are slugs only — no input data, no result data, no URLs you visited. Clear them at any time from Chrome's site settings or by uninstalling the extension.

What the extension sends over the network

  • Once per day: GET https://tools.zerethon.com/api/internal/tools.json to refresh the catalog of available tools. The request carries only the standard browser headers — no user identifier, no token, no telemetry payload.
  • When you open a tool: the extension opens that tool's page on tools.zerethon.com in a new tab. This is a normal browser navigation — the destination site sees a referrer of chrome-extension://… and a ref=ext query parameter so we can measure in aggregate how many visits originated from the extension.

What the extension does with selected text

The right-click "Zerethon: …" context-menu entries take the text you have selected on a webpage and pass it to the corresponding tool by URL-safe base64-encoding it into an ?input=… query parameter on the destination URL. The tool page on tools.zerethon.com decodes that parameter entirely in your browser using its existing client-side JavaScript — the value is never logged on our server. Maximum size is 100 KB; longer selections are dropped.

What the extension does NOT do

  • Read or modify any webpage. There are no content scripts.
  • Inject ads, affiliate links, or referral parameters into pages you visit.
  • Run analytics. No Google Analytics, Mixpanel, Segment, Sentry, or any other telemetry SDK in the package.
  • Access your browsing history, cookies, downloads, or bookmarks.
  • Request the <all_urls> host permission. The only host permission is https://tools.zerethon.com/*.

Permissions used and why

Permission Why
storage Persist recents (local) and favorites (sync).
contextMenus Add the six "Zerethon: …" right-click entries.
sidePanel Let the launcher open in Chrome's side panel.
host_permissions: https://tools.zerethon.com/* Fetch the tool catalog; open tools in a new tab.

Third parties

We do not sell, share, or transfer any user data to third parties. We do not use user data to determine creditworthiness or for lending purposes. We do not use user data for purposes unrelated to the extension's single purpose.

Source

The extension is open-source under the MIT license. You can audit every line at github.com/zerethonapp/extensions. Reproducible builds (npm run build) produce the byte-identical zip submitted to the stores.

Contact

Questions or requests: support@zerethon.com.