Watermark API

Watermark images, video and PDFs with one API call

Send a file URL and the operations to run. Get back a link to the result, or a signed webhook when it is done. Built for your backend and for AI agents.

Get an API key, $1.00 free Read the docs

curl https://api.watermark.ws/v1/images/process \
  -H "Authorization: Bearer $WATERMARK_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "source": "https://example.com/photo.jpg",
    "operations": [
      {"type": "resize", "width": 1600, "height": 1600},
      {"type": "watermark",
       "image_url": "https://example.com/logo.png",
       "x": 40, "y": 40}
    ],
    "output": {"format": "webp"}
  }'

The same processing as watermark.ws

Every request runs on the servers behind our editor and batch jobs.

Images

Watermark with your logo, tiled or placed. Resize, crop, rotate, filters and background removal. JPEG, PNG, WebP, HEIC and more.

Video

Watermark, resize, crop and rotate MP4, MOV and WebM, with progress while it runs. Long videos move to larger servers on their own.

PDFs

Watermark every page, read the page count, or render a page as an image.

Three steps to a watermarked file

1
Get a key

Sign up and create a key in your account. Test keys are free; live keys use your credit.
2
Send the file and the operations

POST a public file URL and a list of operations. The API answers at once with the request, queued.
3
Get the result

Poll the request, or receive a signed webhook, then download the file from its link.

Made to be called by code and by AI agents

Everything a client needs is published in plain, machine-readable form.

An OpenAPI 3.1 spec

Generate a client in any language, or explore it in the interactive reference.

llms.txt and Markdown docs

An agent reads api.watermark.ws/llms.txt and knows how to call every endpoint.

A command-line tool and a PHP SDK

Process a file from your terminal or a script, with JSON output and clear exit codes.

Safe to retry

Send an Idempotency-Key and a retried request never runs or charges twice. Webhooks are signed.

Pay for what you process

Buy credit in advance. Each finished request takes its price from it; failed requests are free.

Start free

$1.00

of credit when you sign up

Images and PDFs
Free test keys, 100 requests a day
No card needed

Request	Price
Process an image	$0.002 / request
Read an image	$0.0005 / request
Process a video after your first purchase	$0.02 / minute
Read a video after your first purchase	$0.001 / request
Save a video frame after your first purchase	$0.002 / request
Process a PDF	$0.004 / page
Read a PDF	$0.0005 / request
Render a PDF page	$0.002 / request

Questions

Do I need a watermark.ws plan?: No. The API runs on credit you buy for it, separate from editor plans. Any watermark.ws account can open it.
Where do my files go?: We fetch the file from the URL you send and keep the result for 7 days behind a signed link that only you get. Then it is deleted.
What happens when a request fails?: It is not charged, and the request says why, with a code your code can act on.
Can I send files from my computer?: For now the file needs a public URL, such as a link from your own storage.

Watermark your first file in a few minutes

Get an API key, $1.00 free Read the quickstart

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