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PDF Watermark

Add a text watermark overlay to PDF pages

POST 10 credits /v1/pdf/watermark

curl -X POST "https://pdf.toolkitapi.io/v1/pdf/watermark" \
  -H "Content-Type: application/json" \
  -d '{
    "url": "https://toolkitapi.io/contract.pdf",
    "text": "CONFIDENTIAL",
    "font_size": 60,
    "opacity": 0.15,
    "angle": 45
  }'

import httpx

resp = httpx.post(
    "https://pdf.toolkitapi.io/v1/pdf/watermark",
    json={
    "url": "https://toolkitapi.io/contract.pdf",
    "text": "CONFIDENTIAL",
    "font_size": 60,
    "opacity": 0.15,
    "angle": 45
  },
)
print(resp.json())

const resp = await fetch("https://pdf.toolkitapi.io/v1/pdf/watermark", {
  method: "POST",
  headers: {
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "url": "https://toolkitapi.io/contract.pdf",
    "text": "CONFIDENTIAL",
    "font_size": 60,
    "opacity": 0.15,
    "angle": 45
  }),
});
const data = await resp.json();
console.log(data);

# See curl example

Response 200 OK

{
  "pdf": "JVBERi0xLjcKMSAwIG9iago8...",
  "page_count": 8,
  "watermarked_pages": 8,
  "file_size": 298750
}

Description

Add a text watermark overlay to PDF pages

How to Use

1

1. Provide the PDF via `pdf` (base64) or `url` (public URL).

2

2. Set `text` to your watermark message (up to 200 characters).

3

3. Optionally adjust `font_size` (8–200, default 48), `opacity` (0.01–1.0, default 0.15), and `angle` (0–360, default 45).

4

4. Optionally set `pages` to watermark only specific pages. Omit for all pages.

About This Tool

PDF Watermark overlays a text stamp on every page — or specific pages — of a PDF document. You control the text, font size, opacity, and rotation angle to create subtle background marks or prominent labels.

Use this to mark documents as "DRAFT", "CONFIDENTIAL", "SAMPLE", or "DO NOT COPY" before sharing. The watermark is rendered as a semi-transparent text layer centered on each page, visible when viewing but not obscuring the underlying content.

The watermark is permanently embedded in the output PDF. It's not a removable annotation — it's merged into the page content stream.

Why Use This Tool

Confidentiality marking — Stamp documents as "CONFIDENTIAL" or "INTERNAL" before distribution
Draft labeling — Mark working documents as "DRAFT" to prevent premature use
Sample branding — Watermark sample documents with "SAMPLE" or "PREVIEW"
Copyright protection — Add ownership text to prevent unauthorized redistribution
Review tracking — Mark documents with reviewer names or dates during approval workflows

Frequently Asked Questions

Can I use multiple watermarks on the same page?

Not in a single request. To add multiple watermark layers, chain requests — watermark the PDF once, then pass the result to a second watermark call with different text or settings.

Is the watermark removable?

No. The watermark is merged into the page content stream, making it a permanent part of the PDF. It cannot be removed by toggling a layer or annotation.

What font is used?

The watermark uses Helvetica, which is a standard PDF base font available in all PDF viewers. Custom fonts are not currently supported.

Start using PDF Watermark now

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