Watermark PDF
Add a custom text watermark to every page of your PDF. Perfect for protecting proprietary documents.
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or drag and drop them here
How a text watermark protects a PDF — and when to add one
The Watermark tool overlays a line of your chosen text across every page of a PDF, angled and semi-transparent so the underlying content stays readable. You control the wording, the font size on a slider from 10 to 150 points, the rotation angle anywhere from 0 to 360 degrees, the opacity, and the exact color through a hex picker. Common stamps include CONFIDENTIAL, DRAFT, INTERNAL USE ONLY, and COPY.
Circulating a draft that must not be mistaken for a final version, sending sample chapters or proposals to prospects, sharing internal figures outside the team that owns them, and marking documents as unapproved are all classic watermark situations. A visible stamp travels with the document: anyone who prints it, photographs the screen, or forwards the file carries your notice along with it, which discourages casual misuse and ends arguments about which revision is current.
The watermark is drawn directly onto each page with pdf-lib inside your browser, and a live preview updates as you drag each slider so you can balance visibility against readability before committing. Because nothing is uploaded, you can safely stamp confidential drafts, unreleased financials, or client materials knowing the file never leaves your device.
How to Add a Watermark to a PDF
Stamp custom diagonal or horizontal watermarks on PDF pages.
- 1
Upload PDF File
Select or drop your PDF document into the watermark tool.
- 2
Configure Watermark Text & Appearance
Type your watermark text, adjust transparency, font size, rotation angle (e.g. 45° diagonal), and color.
- 3
Apply and Download
Click 'Add Watermark' to apply the watermark across all pages and download your stamped PDF.
How to add a watermark to a PDF, step by step
Type your stamp text, tune four sliders and a color, watch the live preview, then apply it to the whole document at once.
- 1
Open the Watermark tool and load your PDF
Drop your file into the upload area on the Watermark page. The tool accepts any standard PDF, and the settings panel appears as soon as the document is loaded.
- 2
Type your watermark text
Replace the default CONFIDENTIAL in the Watermark Text field with your own wording, such as DRAFT, SAMPLE, or your company name. Short text works best; very long phrases can clip at the page edges at larger font sizes.
- 3
Set the size
Drag the Font Size slider between 10 and 150 points. Large sizes around 80 to 120 produce a bold statement across the page, while modest sizes around 30 to 50 read as a discreet label.
- 4
Choose the angle
Adjust the Rotation slider to set the angle in degrees from 0 to 360. Forty-five degrees is the classic diagonal that runs corner to corner; zero degrees gives a flat horizontal banner through the middle of the page.
- 5
Balance the transparency
Move the Opacity slider to control how strongly the stamp reads. Values around 20 to 35 percent keep body text comfortable to read, while higher values make the watermark unmistakable at the cost of contrast.
- 6
Pick a color
Open the color picker and choose any shade, or enter a precise hex value; the current selection is displayed beside the swatch. Light grays and soft brand colors blend politely, while saturated reds and blues demand attention.
- 7
Review the preview, then apply and download
The preview pane superimposes your text on a sample page, rotating and fading in real time as you adjust the controls. When it looks right, click Add Watermark; every page is stamped and the finished file downloads as Rupix_Watermarked followed by the original name.
100% Client-Side Privacy Guarantee
Unlike other online PDF converters, Rupix operates on a zero-upload architecture. All PDF processing occurs locally in your browser memory using WebAssembly. No document bytes are ever uploaded to any server.
Engine Specifications
Supported Input
Standard PDF (.pdf)
Watermark Type
Custom Diagonal/Horizontal Vector Text
Engine
pdf-lib (Vector DrawText Stream)
Opacity Range
5% to 100% Alpha
Privacy
100% Local In-Browser Processing
Browser Support
Chrome, Safari, Firefox, Edge, iOS, Android
Why use Rupix Watermark PDF?
Custom text watermarks (e.g. 'CONFIDENTIAL', 'DRAFT', 'COPY')
Precision angle rotation (-90° to +90°, standard 45° diagonal)
Opacity and transparency slider (10% to 100%)
Custom RGB font color picker and text size scaling
Layering behind or on top of existing PDF text
100% on-device processing with zero data uploads
Frequently Asked Questions
Can I adjust watermark transparency so text remains readable?
Yes, you can set the opacity slider (typically 15%-30%) so the watermark protects your document without obscuring underlying text.
Can someone easily remove the watermark?
Watermarks stamped with Rupix are embedded as vector content streams within the PDF page dictionary. For maximum protection against modification, you can also use our Flatten tool.
Does watermarking work on multi-page PDFs?
Yes, the watermark is automatically applied to every page in the document.
Are my watermarked documents sent to any server?
No. All vector text drawing is performed in your browser's WebAssembly sandbox. Files never leave your device.
Which settings keep the page text readable under the watermark?
Keep opacity low, roughly 15 to 30 percent, choose a moderate font size around 40 points, and stick with the 45 degree diagonal so the stamp crosses text lines obliquely instead of hiding behind them. A light gray or pale brand color interferes less than a saturated primary. The live preview lets you judge the balance before applying anything.
Can I watermark a PDF with a logo image instead of text?
No. This tool draws text watermarks only, so there is no option to place an image or logo behind the content. If you need a graphic mark, one practical approach is to prepare a version of the document that already contains the logo and then use this tool to stamp a text notice such as SAMPLE on top of it.
Does watermarking alter the rest of my document?
Nothing except the stamp itself is touched. Your text, images, links, and formatting are carried through untouched, and the watermark is added as a separate vector drawing layered over each page, so it stays crisp at any zoom level and prints cleanly. The only other change is the Rupix_Watermarked prefix added to the downloaded file name.
Can a watermark be removed from the PDF afterward?
Treat a watermark as a strong notice rather than an absolute lock. Anyone with PDF editing software and patience can attempt to strip an overlay, especially from an untouched file. Running the watermarked copy through the Flatten tool makes casual removal harder by merging the content layers, and distributing PDFs rather than editable originals limits exposure further.