Your file never touches our disk.This tool works entirely in memory and hands the result straight back in the same response — unlike the other tools on this site, there is no 45-minute copy sitting on our server afterwards, because none is ever written.
By ShinobiTools Team · Last updated: August 2026
A draft that shouldn't be mistaken for the final version, or a document that needs CONFIDENTIAL stamped across it before it goes out. Type your text and it's baked diagonally across every page. Nothing is re-compressed — the existing text and images are untouched.
The text you type is drawn once per page, rotated 45° and centred, at low opacity so it does not block what is already there. It becomes part of the page content itself — the same as any other text on the page — not a separate annotation layer.
A watermark that runs corner to corner is hard to crop out of a photo or screenshot of the page, and low opacity keeps the underlying document legible. That is the same convention used on stamped legal drafts and confidential releases.
This tool works entirely in memory and hands the result straight back in the same response — there is no copy sitting on our server afterwards, because none is ever written.
Need the opposite — a watermark taken off a scanned page instead of added? That is a manual retouch, not something this tool does. Want page numbers as well as a stamp? Run the result through Add Page Numbers to PDF next.
Drop the PDF in, type the text you want stamped — CONFIDENTIAL, DRAFT, a company name — and press Add watermark. The download has that text baked diagonally into every page.
Yes. It is drawn at low opacity so the page underneath stays fully readable, the same look as a stamped legal draft.
No, and that is the point. It is drawn as real page content, not a layer that a viewer toggles off, so it stays on the page the same way the rest of the text does.
No. The page's existing content is untouched — the watermark text is added on top, nothing already there is re-drawn or re-compressed.
Yes. Type anything you like before dropping the file — there is no fixed list of presets.
25 pages per file. There is no account, no daily cap, and nothing is stored on our server afterwards.