Watermark a PDF without uploading it
Stamp CONFIDENTIAL, DRAFT, or any text across every page.
Processed on your device — nothing is uploaded. Works offline.
How to watermark a PDF without uploading it
- 1Choose one or more PDFs.
- 2Type the watermark text — CONFIDENTIAL, DRAFT, a client name — and pick gray or red.
- 3Click Apply. The text is stamped diagonally across every page at 25% opacity.
- 4Download the files.
Every step runs in this tab. The site has no upload endpoint, and the page's security policy forbids the browser from contacting any other server — see how that is enforced.
When you'd use it
Drafts and confidential material
Make the status obvious on every page before a document circulates.
Samples and proofs
Mark preview copies so they aren't mistaken for the final version.
Internal documents leaving the building
Stamp who a copy was prepared for, so leaks have a name on them.
Good to know
- The stamp is 60 pt text at 25% opacity, rotated 40°, drawn on every page.
- It's drawn into the page content rather than added as an annotation, so a viewer can't simply toggle it off.
Don't trust us — test us
“Your files never leave your device” is a claim every PDF site makes. Here it is checkable in under a minute, three different ways:
- Watch the network.Open your browser's developer tools, switch to the Network tab, then run the tool. The only requests you will see are the site's own files — none of them carries your document — and once the app is cached there are no requests at all.
- Pull the plug. Load this page, turn off your wifi or switch on airplane mode, then use the tool. It keeps working, because there is no server involved and nowhere to upload to.
- Read the headers. The response headers for this page include a Content-Security-Policy with
connect-src 'self': the browser itself refuses to send anything to another host, whatever the code asks.
The full privacy model, including what we can't protect you from →
Guide
How to edit a PDF without uploading it
Most 'edit a PDF' jobs are one of seven things, and all seven can be done in your browser without the file leaving your machine. Which tool for which job, and the honest answer on editing the text itself.
Frequently asked questions
Can the watermark be removed later?
Not with a click — it is part of the page content, not an annotation. A determined person can still crop or re-render pages, so treat a watermark as a label, not as security.
Can I choose where the watermark goes?
Not yet. It is placed diagonally across the centre of every page, which is what most people want for DRAFT and CONFIDENTIAL stamps.
Are my files uploaded to a server?
No. All processing happens inside your browser using WebAssembly and JavaScript. Our server only serves the app itself — there is no endpoint that can receive files. You can verify this in your browser's network tab, or turn off your wifi after the page loads: everything still works.
Does it work offline?
Yes. After your first visit the whole app is cached by a service worker, so the page loads and every tool works with no connection at all. Load the page, switch on airplane mode, and carry on.
Is there a file size limit?
No hard limit — your device's memory is the ceiling. Files up to a few hundred MB work well on a typical laptop. Very large files may be slow or fail on low-memory devices; nothing is ever truncated silently.
Do I need to create an account?
No. No account, no email, no cookies. The free tools are simply free.
Which browsers work?
Current Chrome, Edge, Firefox and Safari, on desktop and on phones. Phones have less memory, so very large files are better handled on a laptop.