QRkoodi

QRkoodi, commonly called QR code, is a two‑dimensional barcode designed to be read quickly by cameras on smartphones and other imaging devices. It was created by the Japanese company Denso Wave in 1994 to track automotive parts and is named for its emphasis on fast decoding. The format has since become widely used for a variety of data types, including URLs, contact information, product details, and payment data.

Design and data capacity

A QRkoodi is a square grid of black and white modules with distinctive finder patterns in three corners, a timing pattern, and version information. The data is encoded in 1 of 4 error‑correction levels (L, M, Q, H) using Reed–Solomon codes, allowing decoding even when part of the symbol is damaged. QRkoodis come in 40 versions, increasing in size and data capacity. Capacities vary by version and error‑correction level, ranging from small codes that hold a few characters up to large ones that can store thousands of numeric digits (up to 7,089 numeric, 4,296 alphanumeric, 2,953 bytes, or 1,817 Kanji for the largest version at the lowest error correction). Variants include Micro QR Code for small items and iQR Code for higher density.

Usage and standards

QRkoodi is used to encode URLs, contact details (vCard), text, calendar events, and payment information. It is standardized as ISO/IEC 18004 and is supported globally by scanners and smartphone cameras. Because QRkoodi data is not encrypted by default, security relies on the layer above (for example, HTTPS URLs or encrypted payloads). Generate and read tools are widely available, making QRkoodi a ubiquitous method for quick information transfer in advertising, tickets, packaging, and mobile payments.