Kroki vs QR code

Kroki puts a single unified HTTP API in front of two dozen open-source diagram-as-code renderers, including PlantUML, Mermaid, GraphViz, D2, BPMN, Excalidraw, and WaveDrom, so callers send diagram source text and get back an image with no local toolchain to install. A GET request embeds the (deflate+base64-encoded) diagram directly in the URL, making it trivial to drop live diagrams straight into Markdown or HTML. The project and its public instance at kroki.io are free and open source, with self-hosting via Docker documented for anyone who needs a private instance.

goQR.me's QR code API, served from api.qrserver.com rather than the marketing domain, offers two commands: create-qr-code renders a PNG, SVG, or EPS QR image from a data string, while read-qr-code decodes an existing QR image (by URL or upload) and returns the result as JSON. Run by Foundata GmbH, it imposes no request limit beyond reserving the right to reject abusive traffic, and it logs only the requesting referrer/IP, never the QR content itself.