Stamp a diagonal text watermark on every page of a PDF — choose the text, size, color and opacity. Nothing is uploaded.
A draft that should not be mistaken for the final version, a document that needs a visible "CONFIDENTIAL" stamp, a sample PDF that must be marked before sharing — watermarking is a standard way to signal the status of a document. This tool stamps a diagonal text across every page without uploading anything.
The watermark is drawn as semitransparent text at an angle that follows the page diagonal. You control the text, the font size (20 to 120 points), the opacity (8% to 50%) and the color (gray, red, blue or black). The text is drawn on top of the existing content using the Helvetica font.
Everything runs in your browser using the pdf-lib library. The original content is not modified — the watermark is added as an overlay. Text stays selectable and images keep their resolution.
No. The file is read and processed entirely in your browser. Nothing is transmitted, stored or logged.
By someone with a PDF editor, yes — the watermark is drawn as a text element, not burned into the images. For tamper-proof marking, use a professional DRM solution.
At the default 18% opacity the watermark is visible but does not make the content unreadable. Increase the opacity if you need a more prominent stamp.
Not in this version. The tool uses the Helvetica font built into the PDF standard. Image watermarks would require uploading an image file, which this tool avoids by design.
Vai.la turns any URL into a short link with click statistics, QR Code and your own biolink.
Vai.la is not responsible for how the tools are used or for decisions made based on their results.