Guide

Add watermark

Overlay an image or PDF on every page.

You can overlay an image or another PDF onto every page of a PDF document. Provide two inputs — the base document first and the overlay (the watermark/stamp graphic) second — then enable either stamp or watermark on a document / pdf conversion and choose where the overlay is placed with alignment.

How it works

The overlay is applied to every page of the base PDF. The order of inputs matters: the first input is the PDF to stamp, the second is the image (PNG, JPG) or PDF used as the overlay. Common overlay formats are PNG (for transparency), JPG, and single-page PDF.

A transparent PNG overlay gives the cleanest result, since the surrounding area stays see-through regardless of stamp or watermark mode.

Stamp vs. watermark

Both place the overlay on each page — the difference is opacity.

Option Effect Typical use
stamp Opaque overlay drawn on top of the page content. Logos, seals, "APPROVED" / "PAID" marks.
watermark Semi-transparent overlay that lets the page show through. "DRAFT" / "CONFIDENTIAL" background marks.

Set exactly one of them to true.

Alignment

Use alignment to position the overlay on the page.

Value Placement
center Overlay centered on the page (default-style placement).
top Overlay aligned to the top of the page.
bottom Overlay aligned to the bottom of the page.
stretch Overlay scaled to fill the whole page.

Full example

Two remote inputs — the document first, the overlay image second — producing a PDF with an opaque, centered stamp:

{
  "input": [
    {
      "type": "remote",
      "source": "https://example-files.online-convert.com/document/pdf/example.pdf"
    },
    {
      "type": "remote",
      "source": "https://example-files.online-convert.com/raster%20image/png/example.png"
    }
  ],
  "conversion": [
    {
      "category": "document",
      "target": "pdf",
      "options": {
        "stamp": true,
        "alignment": "center"
      }
    }
  ]
}

To make the overlay a semi-transparent watermark instead, swap the options:

{
  "options": {
    "watermark": true,
    "alignment": "stretch"
  }
}

Submit the job with your API key in the x-oc-api-key header:

curl -X POST https://api.api2convert.com/v2/jobs \
  -H "x-oc-api-key: <your-api-key>" \
  -H "Content-Type: application/json" \
  -d @job.json
For the exact options supported by the pdf target, see the format explorer. For the end-to-end job lifecycle, see the getting started guide.

Live options

Pick stamp or watermark to see its options (and a copyable request). Remember to add the overlay as the second input:

Loading options…