Add Watermark to PDF
Type the text you want stamped — DRAFT, CONFIDENTIAL, your name, today's date — and pick an opacity. Every page of the PDF gets the same watermark, drawn diagonally in the center. Runs entirely in your browser.
Why watermark a PDF?
- Stamping DRAFT across a contract before circulating it for early review.
- Marking CONFIDENTIAL across an internal report you're sharing with vendors under NDA.
- Watermarking a photographer's portfolio PDF with their name + © year before sending to a prospective client.
- Tagging an academic paper as REVIEW COPY before sending to peer reviewers.
- Putting SAMPLE across a free-preview chapter PDF being shared publicly.
- Adding a recipient's email or company name as a soft-deterrent watermark on PDFs you'd rather not see leaked.
How it works
Your PDF is loaded with pdf-lib, the watermark text is drawn at 18% of each page's smaller dimension using the Helvetica-Bold standard font, rotated -30°, centered, in light grey at the opacity you pick (10–80%). Every page in the document gets the same watermark. The result is a re-saved PDF you can download. Watermarks are visual overlays — they're not encrypted, signed, or DRM, and a determined recipient can remove them with the right tool. They're a deterrent and a label, not a security feature.
Frequently asked questions
Can a recipient remove the watermark?
Yes, with effort. Watermarks are drawn as text overlays on each page — they're cosmetic, not cryptographic. Someone with Acrobat or another PDF editor could redact or rasterize them out. They're a clear visual label and a friction-cost deterrent, not a DRM lock.
Can I watermark with an image (logo) instead of text?
Not yet — this tool is text-only for now. Image watermarks via JPG/PNG embedding are planned. For now, embed your logo as text (your company name in caps) or use a desktop tool like Acrobat for image watermarks.
Can I watermark only specific pages?
Not from this tool — every page gets the same watermark. For per-page control (e.g., 'cover page no watermark, body pages yes'), split the PDF first with the split-pdf tool, watermark the body pages, then merge back.
Will the watermark appear behind or on top of the content?
On top, drawn last — so it overlays existing text and images. To put a watermark behind content (so it shows through paragraph gaps), you'd need a desktop tool that supports the PDF underlay/overlay feature.
Are my files uploaded?
No. The watermark is rendered locally via pdf-lib. Sensitive PDFs — contracts, medical records, tax documents — stay on your device.
About this tool
Watermarks have been a standard part of business PDF workflows for decades — they're how you label a document's status (DRAFT, CONFIDENTIAL, REVIEW COPY) without touching the underlying content. The conventional answer used to be Acrobat or a third-party SaaS; both work but cost money and, in the SaaS case, require uploading the unwatermarked PDF to a third-party server first — counterproductive when the document is sensitive enough to need a watermark in the first place. Client-side watermarking via pdf-lib avoids the upload entirely. The output isn't a security feature — anyone determined enough can strip a visual watermark — but it's a clear label and a friction cost that does its job in 95% of business contexts.