API

One endpoint, styled SVG out

The same renderer the website uses, exposed over HTTP. No API key, no rate-limit tier, no account. Point it at your own deployment of this app.

Jump to parameters Design one visually first

Endpoint

GETPOST/api/qr

GET takes query parameters, POST takes a JSON body with the same keys. Both return an image/svg+xml document, or a JSON object with an error field and status 400 when something is wrong.

Responses are safe to cache indefinitely — the same parameters always produce the same image. CORS is open, so browser-side calls work.

Examples

curl -o qr.svg \
  "https://your-domain.example/api/qr?data=https%3A%2F%2Fupfrog.online&size=800&dotType=extra-rounded&foregroundStyle=linear&gradientColorA=%2315803d&gradientColorB=%230369a1"

What comes back

Rendered by the endpoint above with a linear gradient and extra-rounded modules.

Parameters

Name	Type	Default	Notes
`data`	`string`	required	The content to encode. Up to 2,000 characters.
`size`	`number`	512	Edge length in pixels, 64–4000.
`margin`	`number`	4% of size	Quiet zone in pixels.
`ecc`	`L \| M \| Q \| H`	Q	Error correction level. Use H with a logo.
`shape`	`square \| circle`	square	Outline of the whole code.
`dotType`	`square \| dots \| rounded \| extra-rounded \| classy \| classy-rounded`	square	Module shape.
`cornerSquareType`	`square \| dot \| extra-rounded \| rounded \| dots \| classy`	square	Corner frame shape.
`cornerDotType`	`square \| dot \| extra-rounded \| rounded \| classy \| dots`	square	Corner dot shape.
`foregroundStyle`	`solid \| linear \| radial`	solid	Whether the foreground uses a gradient.
`foreground`	`colour`	#0f172a	Used when foregroundStyle is solid.
`gradientColorA`	`colour`	#15803d	Gradient start colour.
`gradientColorB`	`colour`	#0369a1	Gradient end colour.
`gradientAngle`	`number`	45	Degrees, linear gradients only.
`background`	`colour`	#ffffff	Background colour.
`transparent`	`boolean`	false	Renders without a background fill.
`backgroundRound`	`number`	0	Background corner radius, 0–1.
`cornerSquareColor`	`colour`	inherits	Overrides the corner frame colour.
`cornerDotColor`	`colour`	inherits	Overrides the corner dot colour.
`logo`	`data URL`	none	Centre image, as a data: URL. POST only in practice.
`logoSize`	`number`	0.4	Fraction of the code covered, 0.1–0.6.
`logoMargin`	`number`	8	Clear space around the logo, in pixels.
`hideBackgroundDots`	`boolean`	true	Clears modules beneath the logo.

Errors

A 400 response carries a JSON body such as {"error":"The `data` parameter is required."}. Unknown values for enum parameters are not rejected — they fall back to the default, so a typo yields a plain code rather than a failed request.

Raster output

The endpoint returns SVG only, which is the right format for print and scales freely. Convert to PNG at the edge with any SVG rasteriser, or use the download buttons in the web generator, which produce PNG, JPG, WEBP and PDF in the browser.