Watermark PDF Online

Stamp a text watermark on every page

Watermarks are useful when you need a document to clearly show its status. Draft proposals, review copies, confidential reports, sample files and internal documents can all benefit from a repeated label that readers notice immediately. This watermark PDF tool adds a text watermark to every page directly in your browser. Type the text, choose the size, opacity, rotation and color, then download a new PDF with the watermark applied. The source PDF stays on your device and is processed by client-side JavaScript only.

Balancing visibility and readability

The tool uses pdf-lib to draw text over each existing page. It does not upload the source PDF to a server and it does not convert pages to images. Large diagonal text with low opacity works well for many pages because it crosses the content but still lets the original text show through. Increase opacity when the watermark must be obvious, or reduce it when the PDF contains dense tables, small print or scanned pages with gray backgrounds. A neutral gray is a safe default, while red or blue can be useful for urgent labels such as DRAFT, SAMPLE or COPY.

What a watermark can and cannot do

This tool creates a visible mark, not password protection, encryption or digital rights management. A determined person with a PDF editor may still be able to alter page content. Use a watermark as a clear communication cue and combine it with appropriate document controls when you need stronger protection. Always open the downloaded PDF before distributing it to confirm that the mark appears on every page as expected and does not cover signatures, totals, form fields or other important content. Since the process is local, you can rerun the tool with a smaller size, lighter opacity or different rotation until the result is easy to read.