UlvixorAdd Watermark to PDF
Upload a PDF, type the watermark text, choose its position and opacity, and apply it to every page of the document with one click. Everything is processed in your browser with pdf-lib, without uploading the file to any server.
How it works
- Select a PDF file from your device.
- Type the watermark text in the corresponding field (defaults to 'CONFIDENTIAL').
- Choose the position: diagonal (rotated 45°) or centered horizontal.
- Adjust the opacity with the slider, between 10% and 80%.
- Click 'Apply watermark' so pdf-lib draws the text — in gray, bold Helvetica, centered — on every page, and download the result as document-with-watermark.pdf.
Use cases
- Mark draft contracts or proposals as 'CONFIDENTIAL' before sharing them.
- Identify working copies with the word 'DRAFT' to tell them apart from the final version.
- Add your company name or a copyright notice over documents you distribute.
- Mark document samples (for example 'SAMPLE' or 'NOT VALID FOR SUBMISSION') before sending them for review.
Use cases
- Mark draft contracts or proposals as 'CONFIDENTIAL' before sharing them.
- Identify working copies with the word 'DRAFT' to tell them apart from the final version.
- Add your company name or a copyright notice over documents you distribute.
- Mark document samples (for example 'SAMPLE' or 'NOT VALID FOR SUBMISSION') before sending them for review.
Common mistakes
- Leaving the text field empty and clicking 'Apply watermark'.The button stays disabled with no text, and the function also rejects empty text with the error 'Type the watermark text'.
- Choosing a very high opacity (near 80%) expecting the original text to stay perfectly legible.The higher the opacity, the more visible the watermark but also the more it interferes with the page content; for documents meant to be read carefully, keep opacity low, around 10-30%.
- Expecting to be able to mark only some pages of the document.The watermark is always applied to every page of the PDF with the same text, position, and opacity; there's no way to exclude specific pages in this tool.
Frequently asked questions
No, the color is fixed at gray; you can only adjust the text, position (diagonal or horizontal), and opacity.
Yes, it's drawn identically on each page of the document; it can't be applied to only some pages.
Diagonal rotates the text 45° and centers it on the page; centered keeps the text horizontal, also centered in the middle of the page.
No. The watermark is drawn with pdf-lib entirely in your browser.
Alternatives
Adobe Acrobat, or printing the PDF through an overlay image with editing software, can also add watermarks. This tool is convenient for doing it in seconds, for free, without uploading a potentially confidential document to an external server.