StampStack Privacy Policy

Effective date: July 13, 2026 · Last updated: July 27, 2026

Short version: StampStack does not collect, sell, or transmit your browsing history. Filtering runs on your device. Settings stay in your browser’s local storage. An optional one-time purchase for dark mode is processed by ExtensionPay (Stripe); browsing history is not sent as part of payment.

Who we are

StampStack is a browser extension that blocks ads and trackers using Declarative Net Request (Manifest V3) and local cosmetic/scriptlet filters. An optional paid add-on can darken ordinary web pages.

Data we collect

We do not collect personal data on StampStack servers. StampStack does not operate analytics, crash reporting, advertising identifiers, or remote logging of browsing activity.

Browsing activity: Not sent to us. Network blocking is applied by Chrome’s Declarative Net Request engine using rules shipped in the extension package.
Settings & allowlist: Stored locally via chrome.storage on your device. Not uploaded.
Statistics: Any on-device counters (e.g. badge hints) stay local when available. StampStack does not sync them to a server.
Page analysis (on your device): To show you what a page connects to, and to power the element picker and your own filters, StampStack reads the current page in your browser — the addresses it references and the elements its rules match. None of this is transmitted anywhere, to us or to any third party. It exists only while the page is open, and the popup is the only thing that ever sees it.
Breakage reports (only if you start one): If you use “Still broken? Tell the developer”, StampStack composes an email and opens it in your own mail app. StampStack does not send it — you read, edit and send it yourself, or close it. The draft contains the site’s hostname and StampStack’s own settings (version, filter-list date, which lists are on, repair step, browser version). It contains nothing about the page itself: no page content, no full URL, and none of what the page report observed.
Optional purchase: If you buy dark mode, ExtensionPay / Stripe process payment and may collect an email for receipt and restore. StampStack caches a local paid flag; browsing history and allowlist are not sent to the payment provider.
SponsorBlock (on by default): The Auto-skip sponsor segments toggle is on by default. While it is on, StampStack asks the community SponsorBlock API (sponsor.ajay.app) which segments to skip. It sends only the first 4 characters of a SHA-256 hash of the YouTube video id — never the video id itself, the page URL, or any account identifier — and the request is made without cookies or credentials. The API answers with every video sharing that 4-character prefix, and the right one is selected on your device. You can also choose which segment types to skip; StampStack asks only for the ones you picked, and turning them all off stops these requests entirely.

Permissions

StampStack requests only what is needed to block ads/trackers (and optional dark mode):

declarativeNetRequest — apply filter rules without reading page content on the network path.
scripting — inject cosmetic filters, approved scriptlets, and optional dark-mode CSS.
storage — save preferences, site allowlist, and license cache.
<all_urls> host access — required so blocking, cosmetics, and optional page darkening can work on websites generally.

Third parties

Filter lists (e.g. EasyList and related community lists) are compiled into the extension when a release is built. StampStack does not download filter lists while you browse, and never contacts a list publisher from your browser.

Optional payments: Dark mode unlock uses ExtensionPay (Stripe under the hood). Contacting ExtensionPay happens only when you open checkout, restore a purchase, or the extension refreshes license status. We do not sell or share browsing data.

SponsorBlock: Segment lookups go to the SponsorBlock community service. Auto-skip is on by default; while it is on, each lookup sends a 4-character SHA-256 hash prefix of the video id (not the video id, not the page URL) with no cookies attached. You can choose which segment types to skip in Options — StampStack requests only the ones you picked — and turning them all off stops these requests entirely.

Children

StampStack is not directed at children under 13 and does not knowingly collect children’s data.

Changes

We may update this policy when the extension’s data practices change. The effective date above will be revised accordingly.

Contact

Questions about privacy: andreas.nelvik.engebretsen@gmail.com or contact the publisher via the Chrome Web Store listing for StampStack.