§ Overlay

Watermark Image API

The watermark endpoint. The overlay travels in its own `overlay` form part, the way /pdf/stamp takes `stamp`. Anchor it to a nine-point gravity or an absolute offset, scale it against the base, blend it, tile it. The result is always the size of the base image.

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Endpoint: POST /image/composite
Inputs: Exactly 1 image
Aux part: overlay — one image
Returns: The encoded image
Limits: 20 MB per file, 50 M pixels. The overlay is capped like the base.
Price: $0.001

§ 01 The request

One POST, and the file comes back.

POST /image/composite

curl -sS --fail-with-body \
  -o marked.png \
  -H "Authorization: Bearer $OHMYWRAP_KEY" \
  -F "file=@photo.jpg" \
  -F "overlay=@logo.png" \
  -F 'options={"gravity":"southeast","opacity":0.6,"scale":0.2}' \
  https://api.ohmywrap.com/image/composite

Options

Options accepted inside the options JSON object
Option	Type	Default	What it does
gravity	string	centre	Nine-point anchor, `northwest` … `southeast`.
left, top	int	—	Absolute offset. An alternative to gravity, not a companion.
blend	string	over	`over` `multiply` `screen` `overlay` `darken` `lighten`.
opacity	number	1.0	0 to 1.
scale	number	—	0 to 1. Sizes the overlay relative to the base’s width.
tile	bool	false	Repeat the overlay across the base.
output	object	—	The shared encode block: format, quality, lossless, effort, progressive, keepMetadata.

§ 03 Nearby

Other image endpoints

All image endpoints

Your first /image/composite call takes one line of curl.

Ten thousand calls cost ten dollars, the pack never expires, and nothing you send is kept.

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10,000 calls for $10. No subscription, no expiry.