Add custom text or image watermarks to any PDF. Control opacity, rotation, size, font, colour and position — fast, private and fully browser-based.
Select a PDF to add a text or image watermark — or drag & drop
Dudi Watermark PDF is a fast, 100% free, browser-based tool from Dudi PDF Editor that adds professional text or image watermarks to any PDF document in seconds. Whether you are marking a draft as CONFIDENTIAL, stamping your company logo onto proposals, protecting your portfolio images from theft, branding shared documents, or warning readers that a file is not final, this tool does it all without installing software, creating an account, verifying an email or paying any hidden fee. Unlike most online PDF watermarkers, your file is never uploaded to a remote server. The entire process runs inside your browser using the pdf-lib JavaScript library — your PDF is read from your device, the watermark is drawn on top of each page, and the finished file stays on your device until you press the Download button. That means your confidential reports, legal documents, academic papers, invoices and internal company files never leave your computer or phone. There is no signup, no watermark added by us, no daily limit and no page-count restriction beyond your device's memory. Dudi Watermark PDF supports two watermark types. Text watermarks let you type any phrase — CONFIDENTIAL, DRAFT, COPY, VOID, SAMPLE, or your own company name — and pick from Helvetica, Courier or Times Roman fonts, any colour, and any size. Image watermarks let you upload your company logo or a custom design in PNG or JPEG format, with a transparent PNG looking the most professional. Both types give you full control over the appearance: opacity from 5 to 100 percent so the watermark can be subtle or bold, rotation from minus 90 to plus 90 degrees with a diagonal look being the most common, size from 20 to 150, and position — centre for a single diagonal mark, tile for a repeated grid that is very hard to remove or crop out, top for a header-style stamp, or bottom for a footer-style stamp. You can also choose which pages receive the watermark: all pages, first page only, last page only, odd pages only, or even pages only, which is handy for books and long reports. A live preview box shows exactly how the watermark will look before you apply it, so you can fine-tune the settings without guesswork. All watermarks are drawn as vector text or embedded images layered on top of the existing page, so the original content of your PDF — text, images, charts, signatures and annotations — is never re-encoded or re-compressed, and quality is fully preserved. The output opens correctly in Adobe Acrobat, Chrome, Edge, Safari, Firefox and every common PDF reader. Because the tool never downloads automatically, nothing is saved to your disk until you choose it: after the watermark is applied, a Download button appears and you decide when to save the file. The downloaded file is always named Dudi PDF Editor Watermark PDF.pdf, and if you watermark another file in the same session it becomes Dudi PDF Editor Watermark PDF (2).pdf and so on, so your files stay clearly identifiable. The layout is fully responsive, so the tab switcher, sliders, preview box and action buttons all stay easy to use on a small Android phone as well as on a large desktop monitor. After the first page load the libraries are cached, so the tool often keeps working even on a weak connection. If you need more tools, Dudi PDF Editor also offers Merge PDF, Split PDF, Compress PDF, Rotate PDF, PDF Page Numbers, Sign PDF, Protect PDF, Unlock PDF, Word to PDF, JPG to PDF, editing, cropping, OCR, image conversion and many other privacy-first utilities that all run locally in your browser with the same no-upload guarantee.