Add a Watermark to a PDF — Text or Logo, 100% In-Browser
Stamp every page of a PDF with a text watermark like "CONFIDENTIAL" or "DRAFT", or with your own PNG/JPG logo. Control opacity, size, color, and position, and watch a live preview of the first page as you tweak the settings. Everything runs locally with pdf-lib — nothing is uploaded, and your document never leaves your device.
Frequently Asked Questions About Watermarking PDFs
How does the Add Watermark tool work?
Upload a PDF, choose a text or image watermark, then fine-tune its size, opacity, color, and position. A live preview of the first page updates as you adjust the controls. When you are happy, hit "Add watermark" — pdf-lib stamps every page and the finished PDF downloads locally.
Does this modify my original PDF?
No. A brand-new PDF is created with the watermark baked in. Your original file is never changed, and nothing is uploaded anywhere.
Which text characters are supported?
Text is drawn with a built-in standard font (Helvetica), which covers printable ASCII and common Latin-1 characters. Unsupported symbols are replaced with "?" so the tool never fails on unusual input.
What is the watermark good for?
Marking documents as "CONFIDENTIAL" or "DRAFT", adding a company logo, or putting a copyright notice on every page of a PDF before sharing it.