About PDF Watermark
The PDF Watermark tool uses pdf-lib to add text watermarks to PDFs entirely in your browser, with customisable text, font size, colour, opacity, rotation angle and position - no upload required. It is ideal for marking contracts, reports, exam papers and certificates with labels like "Confidential", "Draft" or "Sample" to deter unauthorised distribution. The watermark is a semi-transparent text overlay placed on each page at a chosen position - centred, tiled or at custom coordinates. All processing is local, so your document content never leaves your device.
How to Use
- Open the PDF Watermark tool page
- Enter or paste your data into the input area
- View the real-time results and use the copy button to get the output
Use Cases
- Confidential Marking — Add a "Confidential" watermark to internal contracts and financial statements to signal sensitivity and reduce leakage risk.
- Draft Status — Stamp unfinished reports or proposals with "Draft" so incomplete versions are not mistaken for final.
- Sample Protection — Watermark externally shared samples or demos with "Sample" to discourage unauthorised copying.
- Copyright Notice — Add copyright information to courseware, e-books and white papers to assert ownership.
- Exam Anti-Cheating — Watermark electronic exam papers with candidate names or IDs to trace the source of any leak.
FAQ
Can the watermark be removed?
The text watermark overlays page content and cannot be removed by simple text copy. However, professional PDF editors can theoretically delete it - watermarks serve mainly as a deterrent and traceability aid.
Are Chinese watermarks supported?
Due to pdf-lib's built-in font limitations, English and basic Latin characters are supported by default. Chinese watermarks require an embedded CJK font file - English or pinyin labels are recommended.
Are files uploaded to a server?
No. All watermarking happens locally in the browser; your PDF content never leaves your device.
Can I watermark only some pages?
Yes. Specify pages by range, e.g. `1-3,5`; only those pages get the watermark.
Can position and angle be customised?
Yes. Choose preset positions like centred or tiled, or set a custom rotation angle (e.g. 45° diagonal) and opacity to suit your needs.
Will the file get larger?
A text watermark is tiny - typically a few KB - with negligible impact on overall file size.
Comments
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