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PPDF123

Add a Text Watermark to a PDF

Add Watermark repeats your text in a diagonal grid across every page of a PDF. You choose the text, size, angle and color; the text is drawn in Helvetica, so it supports Latin letters, digits and punctuation.

Drag and drop files here, or click to choose

Accepts PDF · up to 500.0 MB per file · up to 20 files at once

You can also paste a file with Ctrl/Cmd+V, or from the clipboard menu.

Watermark repeats your text in a diagonal grid across every page, so a draft or confidential copy stays marked wherever someone looks.

You choose the text, font size, angle and color. The text is drawn in Helvetica, so it supports Latin letters, digits and punctuation; text with characters outside that set, such as Chinese or Arabic, is rejected with an error that names them.

The mark becomes part of the page content rather than a separate annotation. Password-protected files are unlocked for you on this page once you enter the password; API callers run Unlock first.

For a single mark in one spot, use Add Stamp. To place a logo or other image, use Add Image or Overlay PDFs.

Features

  • Repeating text grid on every page
  • Adjustable text, size, angle and color
  • Latin text only (Helvetica)
  • No account or sign-in required

When to use this tool

  • Tile DRAFT across a review copy
  • Mark a packet confidential in Latin letters
  • Repeat a short phrase at 45 degrees

How do I add a watermark to a PDF?

  1. Upload the PDF you want to mark.
  2. Enter the watermark text and set the size, angle and color.
  3. Click Process and download the watermarked PDF.
  4. Check a page: a large, dense grid can cover content.

Limits and edge cases

  • Text only, in Helvetica (Latin characters)
  • Applies to every page
  • Does not make scanned text searchable
  • Upload limit on this website: 500 MB per file, sent in chunks above about 95 MB. A single direct API request body is capped at 100 MB.

Examples

  • The default settings tile a light-gray “PDF123” grid at 45°
  • Size 30 at 45° suits A4 and Letter pages

Privacy for this tool

Files are uploaded over HTTPS, processed in memory or a short-lived temporary directory on our servers, and deleted when your result is ready. We do not keep copies for later browsing, training, or advertising profiles. See the Privacy Policy for retention details and AdSense cookie disclosures.

Frequently asked questions

Can I use a logo image as the watermark?
Not with this tool: it draws text only. Use Add Image or Overlay PDFs to place a logo.
Why is my Chinese watermark rejected?
The font is Helvetica (Western European), which has no Chinese glyphs, so the request fails with an error naming the characters it cannot draw. Use Latin text, or overlay a PDF that already contains the text.
Can someone just switch the watermark off?
Not in a normal viewer: the text is added to the page content itself, not as a removable annotation layer.
Can I watermark one page only?
No. Every page gets the grid.

Last updated:

Call this from code

Every tool on this site is a plain REST endpoint - no account or API key needed for anonymous use. Built for AI agents and developers as much as for browsers.

curl -X POST "https://pdf123.xyz/api/v1/security/add-watermark" \
  -F "[email protected]" \
  -F "watermarkText=PDF123" \
  -F "fontSize=30" \
  -F "rotation=45" \
  -F "customColor=#d3d3d3" \
  -o output.pdf

Also available as an MCP tool for agent clients that speak Model Context Protocol (JSON-RPC 2.0 over POST /mcp). Full API reference

Use it from an AI agent

Skill

Claude Code, Codex, Cursor and other AI agents can run Add Watermark for you with this skill: /skills/pdf123-watermark.md

All agent skills

Files are used only for this processing job and deleted automatically afterward.