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Watermark a PDF without uploading it anywhere

Stamp CONFIDENTIAL, DRAFT or your own wording across every page — angled, faded, and sitting behind the text rather than over it. The file is marked by your own browser, so the document you are trying to control never leaves your machine.

Watermark a PDF — free

No account. No upload. Free while in beta.

A large DRAFT watermark sitting behind the page content, with the body text still fully readable through it.

The documents you watermark are the ones you should not upload

Think about what actually gets watermarked. Draft contracts before they are agreed. Financial statements before they are published. Material under a protective order. Designs that have not shipped. Reports going to one named recipient. The reason you are stamping CONFIDENTIAL across a page is that the page is confidential.

The usual way to do this online is to upload that document to a stranger’s server, have it stamped there, and download it back. The tool has then done the exact thing the watermark exists to discourage. Retention policies and deletion promises are beside the point: a copy left your control.

Here there is no server to send it to. Your browser opens the file, draws the mark, and saves a new copy locally. That is the whole difference, and it is why this page exists separately from the general how to watermark a PDF guide.

What “offline” means here, precisely

Worth being exact, because the word gets used loosely.

The page itself loads over the network, once, like any web page.
After that, stamping needs no network at all. The PDF libraries run in your browser and are served from this site rather than a third-party CDN, so no other party sees a request either.
You can pull the plug after the page has loaded and still open, mark and save a document. That is the honest test, and it works.
There is no installable offline app. Close the tab and you need the network to load the page again.

So it is not offline in the sense of a desktop program you install. It is offline in the sense that matters for a confidential file: the document never travels.

A DRAFT watermark set behind the page content, with the document body text reading clearly through the letterforms.

Marking it

The four that cover most cases: CONFIDENTIAL for material with a restricted audience, DRAFT for something not yet final, COPY to distinguish a duplicate from an original, and DO NOT DISTRIBUTE when the recipient is the boundary. A recipient name or a date works too, and is harder to pass on innocently.

Behind the content puts the mark under the existing text, the way pre-printed stationery works, so the document stays fully legible. On top covers everything, for a deliberate obstruction.
Opacity from a faint tint to solid, set independently of the layer.
Any angle — 45° across the page is the convention.
Every page in one action, or a subset if only part of the document is sensitive.

Save the treatment by name and it comes back on the next document, which matters when everything leaving your office needs the same mark in the same place.

What a watermark does not do

A watermark is a visual deterrent and a provenance marker. It tells a reader how to treat the page, and it makes a leaked copy awkward to explain. That is genuinely useful. It is also the whole of what it does, and it is worth being blunt about the rest:

It does not encrypt the file. Anyone who can open the PDF can read every word of it. If you need the contents protected, you need encryption or access control, not a mark on the page.
It does not prevent copying. The text underneath remains selectable and copyable.
It does not prevent OCR. This one gets searched for specifically, so: text drawn over or under a page does not stop optical character recognition reading the text beneath, and in a PDF that already contains a real text layer there is nothing to OCR in the first place — the text is simply there to be extracted. A watermark heavy enough to defeat OCR would also be heavy enough to defeat a human reader, at which point you have redaction, not a watermark. If the goal is that certain text cannot be read or recovered, the tool for that is redaction that removes the underlying content, and this is not that tool.
It is not tamper-proof. The mark becomes part of the page content rather than a removable annotation, which makes it awkward to strip — but anyone determined can edit a PDF. Keep your unmarked original.

FAQ

Watermarking privately

Does this work without an internet connection?

The page has to load once. After that the stamping runs entirely in your browser — you can disconnect and it keeps working. There is no installable offline version; close the tab and you will need the network again to reopen it.

Is my document uploaded to add the watermark?

No. There is no upload step. The file is read from your disk by your browser, the mark is drawn, and you download the result.

Does a watermark stop someone copying the text?

No. The text underneath is still selectable and still copyable. A watermark marks a document; it does not lock it.

Will a watermark prevent OCR?

No, and you should be sceptical of anything claiming otherwise. See the section above.

Can I watermark every page at once?

Yes, that is the default. You can also restrict it to the current page, odd or even pages, or a custom range like 2, 5-7, 10.

Why is my watermark invisible?

Almost always because it is set to behind the content on a page that is opaque — a scan, or a page with a full-bleed background. Switch it to on top and lower the opacity instead.

Does the watermark become part of the file?

Yes. It is drawn into the page content of the new file you download, not attached as an annotation that lifts off. Your original is untouched.

Mark a document without sending it anywhere

Free while in beta. No account, no upload.

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