← QR code generator

Generate a QR code with curl

Make a QR code from a URL or text, as PNG or SVG, in your colours, with your logo in the centre if you like. Here is the whole call with curl, with the output it produced when we ran it.

Before you start

An API key. Create a free account; it comes with free tokens every month. Put the key in an environment variable so it stays out of your code: export BLOODWEB_KEY=your_key
curl 7.76 or later (for --fail-with-body, which makes curl stop on an error and still show the reason).

The code

Save it as qr-generate.sh and run bash qr-generate.sh.

curl -sS --fail-with-body \
  -H "Authorization: Bearer $BLOODWEB_KEY" \
  "https://bloodweb.net/api/v1/qr-generate?data=https://example.com&size=300" \
  -o qr.png

What you get

Tested 19 October 2026: this exact code ran against our test copy of the API, which runs the same service code as bloodweb.net, and produced this.

It writes qr.png: a PNG image, 300 × 300 pixels, 1 KB.

Change the call

Every option the QR code generator takes. Add or change them the same way as the ones in the code.

data required: What the code holds: a URL, text, a vCard, a Wi-Fi string.
format: Image format. One of: png, svg.
size: Width and height in pixels, including the margin.
margin: Quiet zone around the code, in modules. Scanners want 4; less works on plain backgrounds.
ecc: Error correction: L 7%, M 15%, Q 25%, H 30%. Higher survives damage or a logo, but makes a denser code. One of: L, M, Q, H.
color: Module colour.
background: Background colour, or "transparent".
logo_size: Logo width as a percentage of the code. Bigger logos are harder to scan.

If it fails

A failed call is not charged. The answer is JSON with an error object; curl stops with an error, and that JSON lands in qr.png instead of the result, so open it as text to read the reason. The usual ones:

401 missing_key or invalid_key: BLOODWEB_KEY is not set in the shell that runs the code, or the key was revoked.
400 bad_param: a value is wrong or missing. The message names the parameter.
402 insufficient_tokens: the balance does not cover the call. Top up in the dashboard.
429 rate_limited: too many calls at once. Wait the seconds in the Retry-After header and send it again.

Every code and its fix is in the docs.

The QR code generator page: every option, the limits, and Try it now in your browser.
Getting started: keys, errors and rate limits for all the services.