Free Chrome extension
Postmetry Web Inspector
What a page sends during your visit, to whom, and what your browser keeps. You start an inspection on the tab you choose, browse, and stop it: the report reads in a few lines.
Free, no account. In French and English.
What the report shows
- The path For instance a click in an email: the email platform's click redirector, the identifier carried by the link, the pages visited.
- Who received what For each service contacted, whether the identifier that came with the link, the page address or a browser identifier appears in what was sent to it.
- What your browser keeps The cookies created during the visit, by owner, and those that existed before.
- What the report cannot see In particular what a site passes on from its own servers.
An appendix unfolds each service on all its evidence: the requests, the exact place of each value found, the cookies sent, the vendor's documentation when it exists. Each finding states its level: observed in the requests, or deduced from a documented signature.
Everything stays on your computer
- The extension sends no request, neither to Postmetry nor to anyone else, and requires no account.
- Values are replaced by a fingerprint at capture, under a key that disappears at the end of the session.
- Sessions are erased after seven days, or at any time from the panel.
- An HTML report or a JSON export is created only when you ask for it; the report loads no resource and contains no link.
The privacy policy has a section on the extension.
What it does not do
- The report says what was sent, never what the service does with it, and carries no score and no verdict.
- The extension observes without blocking or changing anything.
- What you declare you did with the cookie banner — refused, accepted, left unanswered — appears in the report as a declaration: the extension does not detect it.
Questions
Does Postmetry have a Chrome extension?
Yes. Postmetry Web Inspector is a free Chrome extension, published on the Chrome Web Store. It shows what a page sends during your visit, to whom, and what your browser keeps.
Does the extension send data to Postmetry?
No. It sends no request, neither to Postmetry nor to anyone else, and requires no account. Sessions stay in your browser and are erased after seven days, or at any time from the panel.
How does it relate to the email audit?
The audit reads an email as it arrives, without loading an image or following a link. The extension shows what happens when you click: the email platform's click redirector, the identifier carried by the link, and which services the landing page sends it to.
Why does it ask for access to websites?
This access is requested when you start an inspection, and can be withdrawn at any time. Without it, Chrome only shows requests to the page's own site, and no third-party service can be observed. The extension loads nothing from these sites.