Package io.nayuki.qrcodegen

Generates QR Codes from text strings and byte arrays.

This project aims to be the best, clearest QR Code generator library. The primary goals are flexible options and absolute correctness. Secondary goals are compact implementation size and good documentation comments.

Home page with live JavaScript demo, extensive descriptions, and competitor comparisons:


Core features:

  • Available in 6 programming languages, all with nearly equal functionality: Java, TypeScript/JavaScript, Python, Rust, C++, C

  • Significantly shorter code but more documentation comments compared to competing libraries

  • Supports encoding all 40 versions (sizes) and all 4 error correction levels, as per the QR Code Model 2 standard

  • Output format: Raw modules/pixels of the QR symbol

  • Encodes numeric and special-alphanumeric text in less space than general text

  • Open source code under the permissive MIT License

Manual parameters:

  • User can specify minimum and maximum version numbers allowed, then library will automatically choose smallest version in the range that fits the data

  • User can specify mask pattern manually, otherwise library will automatically evaluate all 8 masks and select the optimal one

  • User can specify absolute error correction level, or allow the library to boost it if it doesn't increase the version number

  • User can create a list of data segments manually and add ECI segments

Optional advanced features:

  • Encodes Japanese Unicode text in kanji mode to save a lot of space compared to UTF-8 bytes

  • Computes optimal segment mode switching for text with mixed numeric/alphanumeric/general/kanji parts


Simple operation:

import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
import io.nayuki.qrcodegen.*;

QrCode qr = QrCode.encodeText("Hello, world!", QrCode.Ecc.MEDIUM);
BufferedImage img = toImage(qr, 4, 10);  // See QrCodeGeneratorDemo
ImageIO.write(img, "png", new File("qr-code.png"));

Manual operation:

import java.util.List;
import io.nayuki.qrcodegen.*;

List<QrSegment> segs = QrSegment.makeSegments("3141592653589793238462643383");
QrCode qr = QrCode.encodeSegments(segs, QrCode.Ecc.HIGH, 5, 5, 2, false);
for (int y = 0; y < qr.size; y++) {
    for (int x = 0; x < qr.size; x++) {
        (... paint qr.getModule(x, y) ...)
  • Class Summary
    Class Description
    An appendable sequence of bits (0s and 1s).
    A QR Code symbol, which is a type of two-dimension barcode.
    A segment of character/binary/control data in a QR Code symbol.
    Splits text into optimal segments and encodes kanji segments.
  • Enum Summary
    Enum Description
    The error correction level in a QR Code symbol.
    Describes how a segment's data bits are interpreted.
  • Exception Summary
    Exception Description
    Thrown when the supplied data does not fit any QR Code version.