Cachety’s home page, with a specimen ID in the preview. Image: Cachety, via cachety.com.
A bare scan of your passport can be reused for anything. Cachety stamps each copy with what it is for, who it is for and the date, entirely inside your browser, so the file never leaves your device.
You drop in a passport, payslip or bank statement and type a line such as “Rental application, Martin Lettings, 11/10/2026”. Cachety tiles it diagonally across every page. Ready-made templates for housing, bank, job, tax and more fill in the wording, and a button adds today’s date. The point is that a leaked copy is only good for the one thing it was made for.
The details go past stamping. Cachety can black out an IBAN or a photo so the content is actually removed, not just covered; it rebuilds each page from pixels, which drops selectable text, metadata and photo GPS. It can make one personalised version per recipient (up to 20) in one download, add a date and unique reference so you can trace where a copy turned up, shrink files to 1, 2, 5 or 10 MB for upload portals, and lock the PDF with AES-256. It reads PDFs and common images, including iPhone HEIC, up to 200 MB and 500 pages, and runs on phones.
The privacy claim is checkable. The site is a static export with no server to receive a file, and its Content-Security-Policy header limits connections to the page’s own origin, so the browser itself refuses requests to anywhere else. The README suggests the test: load the page, switch on airplane mode, and watermark a document. The code is AGPL-3.0 on GitHub and the site is free, with no account. It is made in France by Amir Moradi and comes in 11 languages.
The caveats are the author’s own. A watermark discourages reuse and traces leaks; the FAQ concedes nothing stops someone photographing or retouching a document. Output is rebuilt from page images, so expect text you cannot select or search. The password applies to the download, not the preview. It is also new: the GitHub repository was created on 11 October 2026, so it has little track record. Funding is optional donations, and the FAQ says it may one day show a few hand-picked sponsored links, never trackers.