QR code libraries compared

For generation: qrcode on npm (MIT) and segno or python-qrcode in Python cover most needs; qr-code-styling adds design. For decoding: zxing-cpp is the actively maintained engine with bindings everywhere; zbar is fast but aging; quirc is tiny for embedded. Generation and decoding are different problems: most projects need one library from each column.

Two ecosystems, not one

Generating a QR code and reading one are unrelated problems that happen to share a name. Generation is deterministic maths: encode, add Reed–Solomon codewords, mask, render. Decoding is computer vision: find the code in a noisy image, correct perspective, sample modules, undo the maths. Libraries almost never do both well, so most real projects pick one from each table.

Generation libraries

Library	Language	Licence	Notes
`qrcode` (npm)	JavaScript	MIT	Pure JS, no native deps, PNG/SVG/terminal output. The default choice in Node.
`qrcode.react`	React	ISC	Renders to canvas or SVG as a component.
`qr-code-styling`	JavaScript	MIT	Module shapes, gradients, logos, the styling layer others lack.
`qrcode` (PyPI)	Python	BSD	Long-standing default; PIL and SVG output.
`segno`	Python	BSD	Pure Python, no dependencies, Micro QR support, very complete spec coverage.
ZXing (Java)	Java/Android	Apache-2.0	The historic reference; the Java project is in maintenance mode.
`go-qrcode`	Go	MIT	Simple PNG generation.
`@useqr/core`	TypeScript	MIT	UseQR's own engine: matrix, styled SVG, typed payload builders, decode-verify loop.

Generation is a solved problem, so choose on the secondary axes: native dependencies (none, ideally. It is what makes a library work in serverless), SVG output (needed for print), and whether styling is in scope.

Decoding libraries

Library	Language	Licence	Notes
zxing-cpp	C++	Apache-2.0	The actively developed rewrite of ZXing; bindings for Python, WASM, iOS, Android.
zxing-wasm	Browser/Node	MIT wrapper	WebAssembly build of zxing-cpp; same engine in browser and server.
zbar	C	LGPL-2.1	Fast and battle-tested; the original project stalled, a community fork carries it.
pyzbar	Python	MIT	Thin wrapper over zbar; needs the zbar shared library installed.
quirc	C	ISC	A few thousand lines, no dependencies, built for embedded and microcontrollers.
jsQR	JavaScript	Apache-2.0	Pure-JS decoder; convenient, but development has largely stopped.

Maintenance status is the honest differentiator here. The original Java ZXing announced maintenance mode; jsQR has been quiet for years; zbar survives through a fork. zxing-cpp is the one decoding engine with clearly active development and first-party bindings on every platform, which is why UseQR uses zxing-wasm for its scanner, its decode API and its CI. A deeper decoder comparison: ZXing vs quirc vs zbar.

Pick by use case

You are building	Generation	Decoding
Node service or script	`qrcode` (npm)	zxing-wasm
React front-end	`qrcode.react` or `qr-code-styling`	BarcodeDetector + zxing-wasm (pattern)
Python pipeline	`segno` or `qrcode`	zxing-cpp (`pip install zxing-cpp`)
Android/iOS app	platform libraries or ZXing ports	zxing-cpp bindings / ML Kit
Microcontroller	custom (generation is small)	quirc
No dependencies allowed	keyless API	`POST /api/v1/decode`

The gap no library fills alone

No generation library can tell you whether its own styled output still scans. That requires rasterising the result and running a real decoder over it. If you generate codes that will be printed, wire generation and decoding together into a decode-verify loop; it is a few lines once you have one library from each table.

FAQ

What is the best QR code library for JavaScript?

qrcode on npm for plain generation: pure JS, MIT, no native dependencies. Add qr-code-styling if you need module shapes, gradients or logos, and zxing-wasm if you also need to decode.

What is the best QR code library for Python?

segno and qrcode are both solid BSD-licensed generators; segno is pure Python with unusually complete spec coverage. For decoding, zxing-cpp's official Python binding is the actively maintained choice over pyzbar.

Is ZXing still maintained?

The original Java ZXing project is in maintenance mode, but zxing-cpp (a C++ rewrite with Python, WebAssembly and mobile bindings) is actively developed and is the practical successor for new projects.

Can one library generate and decode QR codes?

A few try, but the strong tools specialise: generation is deterministic encoding while decoding is computer vision. The common production setup is one generator plus one decoder, connected by a verify step in tests.