Documentation

Technical articles on barcodes, GS1 and ZPL, each linked to the matching tools.

• Barcode not scanning? A checklistWhy a barcode does not scan and how to find out: scanner settings, wrong data, quiet zone, size, contrast, print quality, inverted or mirrored codes, with tools to check each point.
• Barcode quiet zones: how much margin each symbology needsMinimum quiet zones for EAN-13, EAN-8, UPC, Code 128, GS1-128, ITF-14, Code 39, QR Code, Data Matrix, PDF417 and Aztec, in modules, with how to convert them to mm and dots.
• Developer APIREST API for GTIN validation, GS1 parsing, barcode generation, ZPL rendering and validation, barcode-to-ZPL and batch validation. Free API key, 1,000 requests per day.
• GS1-128 and FNC1 explainedHow GS1-128 encodes Application Identifiers, when an FNC1 separator is needed, what scanners transmit (]C1, GS) and the most common encoding mistakes.
• GS1 DataMatrix vs QR Code: which one to useHow GS1 DataMatrix and QR Code differ in error correction, shape, size and GS1 support, when to use which, and how scanners identify them (]d2, ]Q1, ]Q3).
• GS1 Digital Link explainedWhat a GS1 Digital Link URI is, how GTIN, batch, serial and expiry date are placed in path and query, which domain to use, and how to check a URI.
• How the GTIN check digit is calculatedStep-by-step calculation of the GS1 mod-10 check digit for GTIN-8, GTIN-12 (UPC-A), GTIN-13 (EAN-13), GTIN-14, SSCC and GLN, with a worked example.
• ZPL basics: the commands every label usesA first ZPL label explained line by line: ^XA, ^XZ, ^PW, ^LL, ^FO, ^A, ^FD, ^FS, ^GB, ^BY and ^BC, with coordinates in dots and the most common mistakes.
• ZPL dots and printer resolutionWhy ZPL works in dots, how 203, 300 and 600 dpi printers really measure, how to convert mm and inches to dots, and how to choose a barcode module width.