Add text watermarks and stamps to your PDF pages for free in your browser. Customize font size, opacity, rotation, and color. No upload —
Watermarks communicate intent visually — DRAFT, CONFIDENTIAL, branded by X — so recipients do not confuse a review copy with a final deliverable. OpenPDF stamps text or image watermarks with adjustable font, size, colour, rotation and opacity, and lets you preview the composition before exporting. Everything renders locally with pdf-lib so the watermarked PDF never touches a server.
A flattened watermark is baked into the pixels of the page and is hard to remove cleanly, but modern PDF tools can sometimes undo a text overlay. For strong protection, combine with a large opacity and place over the main content.
Yes, in addition to text. Upload a logo PNG (ideally with a transparent background) and position it with the same controls as text watermarks.
Yes. Choose a page range — all pages, a custom range, or specific individual pages.
No. Watermark rendering happens on your PDF locally in the browser.
OpenPDF is an independent project built around one principle: the PDFs you edit should never leave your device. Every tool — merge, split, sign, organize, annotate, compress, watermark, add page numbers — runs entirely in your browser using WebAssembly and modern JavaScript APIs. There is no upload step, no account, no email harvesting, and no premium tier gating the useful features. The codebase and the third-party scripts loaded for analytics and advertising are visible in the page source — Google AdSense and Google Analytics 4 load only after you accept cookies in the consent banner — so anyone can audit what is running before trusting the tool with sensitive contracts, scanned IDs, or financial documents.