Add watermark

api2convert can add a watermark to PDF documents and videos. To watermark a PDF, overlay an image or another PDF onto every page: 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. To watermark a video, overlay an image (a logo or watermark) or another video with the overlays option — see Watermark a video at the end of this guide.

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.

Stamp vs. watermark

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

Set exactly one of them to true.

Alignment

Use alignment to position the overlay on the 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 '{
    "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"
            }
        }
    ]
}'

Live options

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

Watermark a video

To watermark a video, add the overlays option to a video conversion (for example mp4). Each overlay draws an image — a logo or watermark — or another video on top of the output. Unlike the PDF watermark, a video overlay references its graphic by input_id, so it takes two requests: create the job with both files, read the overlay input's id, then add the conversion.

Overlay options

Step 1 — create the job with both inputs

Add the base video first and the overlay image second. The response returns each input with an id — note the overlay's id for the next step.

curl -X POST "https://api.api2convert.com/v2/jobs" \
  -H "x-oc-api-key: <your-api-key>" \
  -H "Content-Type: application/json" \
  -d '{
    "input": [
        {
            "type": "remote",
            "source": "https://example-files.online-convert.com/video/mp4/example.mp4"
        },
        {
            "type": "remote",
            "source": "https://example-files.online-convert.com/raster%20image/png/example.png"
        }
    ]
}'

Step 2 — add the conversion with the overlay

Reference the overlay input by its id and place it with origin, position_x / position_y and opacity:

curl -X POST "https://api.api2convert.com/v2/jobs/<job-id>/conversions" \
  -H "x-oc-api-key: <your-api-key>" \
  -H "Content-Type: application/json" \
  -d '{
    "target": "mp4",
    "options": {
        "overlays": [
            {
                "input_id": "<overlay-input-id>",
                "origin": "bottom-right",
                "position_x": 20,
                "position_y": 20,
                "opacity": "0.5"
            }
        ]
    }
}'