2Dcode

2Dcode is a class of two-dimensional barcodes designed to store data in a matrix layout rather than a single linear row. Each code is made of a grid of black and white modules that encode alphanumeric data, binary data, or URLs. Because they can be scanned with cameras, they are usable by smartphones and standard barcode readers without specialized equipment.

The most widely known 2D codes include QR codes, Data Matrix, Aztec Code, and PDF417. They differ in density, size, and error correction schemes, but share the ability to recover information even if part of the symbol is damaged. Data capacity depends on the symbol type, size, and chosen error correction level, with QR codes offering several kilobytes in typical configurations.

Many 2D codes are governed by formal international standards. For example, QR codes are standardized as ISO/IEC 18004, Data Matrix as ISO/IEC 16022, Aztec Code as ISO/IEC 24778, and PDF417 as ISO/IEC 15438. Software libraries and hardware scanners implement these standards, enabling interoperability across devices and applications.

Common applications include product labeling, ticketing, inventory management, contact information exchange, and mobile payments. They are favored for compact data storage, fast scanning, and ability to hold non-text data such as contact cards or mapped geolocations. However, uses may raise privacy concerns, and codes require adequate printing or display size and good contrast to ensure readability.

Limitations include dependence on line of sight, potential degradation from printing or damage, and risk of tampering or spoofing if the symbol is not secured. When used in security-sensitive contexts, codes should be combined with authentication or encryption.