Turn a text or a URL into a QR code. The picture stays black on white so a camera can read it.
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A QR code is a square matrix of dark and light modules. A camera finds three large squares in the corners and reads the bits. Denso Wave released the design in 1994, and ISO/IEC 18004 standardizes it.
This page encodes the UTF-8 bytes of the text in byte mode, error correction level M, versions 1 to 20. Level M can recover a symbol when about 15 percent of the modules are damaged. A quiet zone of four modules surrounds the symbol.
https://example.com
A version 1 or 2 symbol, error correction M, with a four-module quiet zone.
café
The bytes are UTF-8: c, a, f, then C3 A9 for é. A reader that expects Latin-1 will not match.
Light gray modules on a photo
Black modules on a white quiet zone
Versions 1 to 20 at level M hold at most 666 UTF-8 bytes. A longer text shows an error instead of a symbol that a reader would reject.
A QR code is not a secret. Anyone who can see the picture can read the text. Do not put a password or a private key in it.
Eight mask patterns exist. The page keeps the one with the lowest penalty score from ISO/IEC 18004, and writes that choice into the format bits. Another mask of the same data is still a valid symbol.
The share link stores the text. The symbol is drawn again. Anyone who has the link can read that text.
Masahiro Hara and his team at Denso Wave developed the QR code in 1994 so car factories could scan parts faster than with a barcode. QR stands for Quick Response. Denso Wave published the patent for free use.
Level L recovers about 7 percent, level M about 15 percent, level Q about 25 percent, and level H about 30 percent. This page uses M, the level most general-purpose symbols use.