Symbology
A symbology is the set of rules that defines how data is converted into the bars, spaces, and modules of a barcode — the "language" a barcode is written in.
What You Need to Know
A symbology specification defines every physical and logical property of a barcode: which characters it can encode, how each character maps to bar and space patterns, how the symbol starts and stops, whether a check digit is required, and how much quiet zone must surround it. Code 128, EAN-13, and QR Code are three different symbologies — a scanner cannot read a Code 128 symbol while expecting EAN-13, because the underlying languages are unrelated.
Symbologies are standardized by bodies such as ISO/IEC (e.g. ISO/IEC 15417 for Code 128) and application organizations such as GS1, which layer numbering systems and data rules on top of a symbology. Choosing a symbology is usually the first technical decision in any barcode project, because it determines scanner compatibility, data capacity, and print tolerance.
Where Symbology Applies
A high-density, variable-length linear barcode that encodes all 128 ASCII characters, and the backbone symbology of modern logistics.
Generate Code 128 →The 13-digit retail point-of-sale barcode used on consumer products worldwide outside North America.
Generate EAN-13 →The dominant 2D matrix barcode: up to 7,089 digits in a square symbol with selectable error correction.
Generate QR Code →The classic self-checking alphanumeric barcode: 43 characters, simple structure, still everywhere in industry.
Generate Code 39 →A dense digits-only linear barcode that interleaves bar and space character pairs — logistics workhorse for numeric data.
Generate ITF (Interleaved 2 of 5) →