Privatus Analytics – Block my visits (browser extension)

A Manifest V3 WebExtension for Chrome (and Chromium browsers) and Firefox that stops your own visits from being counted by Privatus Analytics on the sites you choose — handy for site owners, editors and developers.

• Popup toggle for the current tab: "Don't count my visits on this site" (covers the domain and its subdomains; a leading www. is dropped).
• Options page: list of sites, the two exclusion modes, custom tracker endpoints.
• Vanilla JS, no bundler, no dependencies, no remote code, no telemetry, no analytics. The only state is the site list and settings in chrome.storage.local (extension storage) plus a per-tab counter in storage.session (memory).

How it works

Mode A — opt-out flag (the official mechanism). When you enable a site, the extension asks for access to that site only (optional_host_permissions, requested at toggle time) and registers a content script for it with chrome.scripting.registerContentScripts. At document_start it sets localStorage.privatus_optout = "1" in the site's origin — exactly what privatus.optOut() does — and pa.js then sends nothing. Toggling off removes the flag immediately in the current tab and, for 30 days, on your next visit to any other origin of that site (subdomains have separate localStorage). No content script ever runs on sites you did not list.

Mode B — request blocking. declarativeNetRequest dynamic rules block POST requests whose URL matches a tracker endpoint pattern when the request is initiated by a listed site (condition.initiatorDomains). The default pattern is /api/event^ (urlFilter syntax: ^ = end or separator). Add more patterns if you need them, e.g. privatusanalytics.com/api/event. Blocking rules need no host permission, so Mode B works even if you decline site access.

Both modes are on by default; either can be switched off on the options page.

Badge counter

• Chrome: the extension calls declarativeNetRequest.setExtensionActionOptions({ displayActionCountAsBadgeText: true }), so the toolbar badge shows how many tracker requests were blocked on the current tab (maintained by the browser). We deliberately do not use onRuleMatchedDebug — it only exists for unpacked extensions — nor the declarativeNetRequestFeedback permission. The popup additionally reads getMatchedRules({ tabId }), which activeTab allows after you click the button.
• Firefox / Mode B off: the badge counts opted-out page loads: the Mode A content script tells the background when a page on a listed site contained a Privatus Analytics tracker script while the flag was set (those visits were skipped by pa.js itself, so there is no request to count). Setting badge text would hide the DNR count, so this fallback is only used when the DNR count is unavailable.

Limitations

• Mode A sets the flag asynchronously at document_start; on the very first visit a fast inline/non-deferred tracker could send one pageview before the flag exists. Mode B covers that (and the flag persists for later visits).
• Custom tracker endpoints on the same path as other POST APIs of your site would also be blocked for pages on listed sites — use a specific pattern.
• The flag is per browser profile; incognito/private windows need the extension allowed there.

Install (development / unpacked)

src/ is loadable as-is in both browsers (the manifest carries background.service_worker for Chrome and background.scripts for Firefox; each browser ignores the other key with a warning).

• Chrome: chrome://extensions → Developer mode → Load unpacked → src/.
• Firefox (128+): about:debugging#/runtime/this-firefox → Load Temporary Add-on → src/manifest.json.

Build store packages

node scripts/build.mjs          # dist/chrome, dist/firefox with browser-specific manifests
node scripts/build.mjs --zip    # also dist/*.zip (needs `zip`)

• dist/chrome/manifest.json: background.service_worker only, no browser_specific_settings.
• dist/firefox/manifest.json: background.scripts only (event page), gecko id block-my-visits@privatusanalytics.com, data_collection_permissions: none.

Permissions

Permission	Why
storage	Your site list and settings (extension storage only).
declarativeNetRequest	Mode B blocking rules.
scripting	Register the opt-out content script for listed sites; set/remove the flag in the current tab.
activeTab	Read the current tab's hostname when you open the popup.
optional host access (per site)	Requested only when you enable a site, for Mode A.

Tests

Pure helpers (hostname normalisation, DNR rule builder, settings updates, manifest variants) are tested with the Node test runner:

docker run --rm -v "$PWD":/w -w /w node:22 sh -c 'node --test'

License

MIT — see LICENSE.