Data Matrix
The 2D symbology that shrinks to a few millimetres — which is why it's laser-etched onto circuit boards and surgical instruments rather than printed in ads.
The grid is recognised by its L-shaped finder pattern: two solid edges that give the reader its orientation, and two opposite edges of alternating modules that state the grid size. The current variant, ECC 200, carries Reed-Solomon correction and reads even with a chunk torn away. Developed by the American firm International Data Matrix in the late 1980s, standardised as ISO/IEC 16022.
Where the QR code won the public, Data Matrix took industry: it works at extremely small sizes and is engraved, etched or dot-peened straight into metal and plastic — aircraft parts, circuit boards, scalpels that must be traced through a hundred sterilisation cycles. The GS1 variant sits on European pharmaceutical packaging, where since 2019 every box carries its own serial number.