1Your documents
2Details: what it's for, and who gets it
Or pick one:
Who will receive it?
The person or company you're sending it to, like the letting agency. Their name is printed on the copy, so nobody else can pass it off as theirs.
Your watermark
Fill in what it is for, and who gets it
3Review, then download
Drop a document to get started.
Add a document first.
Your documents never leave your device
Most watermark websites upload your ID to their servers. Cachety doesn't: all the work is done by your browser, on your own phone or computer.
Processed on your device
Your files stay in your device's memory. Close the tab and everything is gone.
Blocked by design
The page forbids your browser from sending data to any other website. Even if something went wrong, your files couldn't leave.
No account, no tracking
No sign-up, no tracking cookies, no visitor analytics, no ad networks.
Open source and verifiable
The code is public. Anyone can read it, check it, or host their own copy of the site.
Check it yourself: the aeroplane mode test
Open this page, then switch off the internet (aeroplane mode). Drop in a document: Cachety still works. Proof that nothing goes over the internet.
How it works
- 1
Drop your document
A PDF or a photo, even one taken on an iPhone. Several at once if you need to.
- 2
Say what it's for
For example “Rental application, Martin Lettings, 11/10/2026”. Ready-made templates are included.
- 3
Check, then download
The preview shows exactly what you'll get. The watermarked file is saved to your device.
Everything you need to protect a copy
Watermark across the page
Repeated diagonally and blended into the image: it can't be deleted by simply editing the PDF.
Black out information
Hide an account number, a tax reference or a photo. The content is really removed, not just covered.
A unique code on each copy
When you edit the text, add a short code that is different on every copy: if one turns up somewhere, you'll know where it came from.
One copy per recipient
Add each recipient: everyone gets their own copy, with their name on it, in a single download.
A password made for you
Lock the file with 12 random words, easy to read out over the phone, and AES-256 encryption.
Hidden data removed
Selectable text, metadata and the GPS location of photos are stripped from the final file.
Small enough for any website
If a website or an email refuses your file, shrink it to 10, 5, 2 or 1 MB.
Works on your phone
iPhone and Android, HEIC photos included. Add Cachety to your home screen like an app.
Frequently asked questions
Are my files uploaded to a server?
No, never. The site doesn't even have a server that could receive a file. Your browser does all the work, and the page technically forbids it from contacting any other website. The aeroplane mode test proves it in ten seconds.
Is it really free? What's the catch?
There isn't one: no account, no paid version, no data collected. Because nothing is processed on a server, hosting the site costs almost nothing, and the open-source code guarantees it stays free. To fund its development, Cachety relies on optional donations, and may one day show a few hand-picked sponsored links (encryption tools, open-source software…). Never ads that track you, and never anything based on your documents.
Which files can I watermark?
PDFs and images: JPG, PNG, iPhone photos (HEIC), WebP, GIF, BMP and AVIF. Up to 200 MB per file and 500 pages per PDF, several files at once.
Can the watermark be removed?
Not by editing the PDF: the watermark is part of the image of each page. To be honest, nothing stops someone photographing or retouching a document. A watermark discourages reuse and lets you trace where a leak came from.
What should I write in the watermark?
Three things: what the copy is for, who you're sending it to, and the date. For example “Rental application, Martin Lettings, 11/10/2026”.
Does it work on my phone?
Yes, on iPhone and Android. Open cachety.com in your browser, tap the drop area and pick a photo or a PDF. You can also add Cachety to your home screen.
Practical guides
Step-by-step help for everyday situations.
- How to watermark your ID and documents for a letting agent or landlordRenting a flat? Watermark your passport, payslips and bank statements for a letting agent in a minute, free, without uploading them anywhere.
- How to watermark a copy of your passport or driving licence before emailing itWatermark a copy of your passport or driving licence before you email it. Free, no account, and your photo never leaves your phone or computer.
- How to send bank statements and payslips safelyNeed to send bank statements or payslips? Learn what to watermark and what to black out, like account numbers, before you hit send. Free and private.
- How to properly redact a PDF or image for freeRedact a PDF for free and make sure hidden text is really gone. Why black boxes often fail, and how to black out details safely in your browser.
- How to watermark documents on an iPhone or Android phoneWatermark documents and photos on your iPhone or Android phone, free and without an app store download. HEIC photos supported, nothing uploaded.
- How to password-protect a PDF for free, without uploading itPassword-protect a PDF for free, right in your browser. Strong encryption, an easy-to-read password made for you, and no upload.
Free, open source, made in France
Cachety is free, open-source software (AGPL licence). Its code is open to everyone and will stay that way. It builds on Filigrane Local and Filigraneur, two open-source French projects.
Designed and maintained by Amir Moradi · GitHub
Support Cachety
Cachety is free and will stay free. But it takes time, and the domain name and development tools cost money. If Cachety helped you, a small donation keeps it going.
Make a donationOptional. Payment happens on GitHub Sponsors, outside this site.