ZPL

ZPL (Zebra Programming Language) is a page description language for the thermal and thermal-transfer printers made by Zebra Technologies. Rather than rasterised graphics, the host sends a text stream of commands — prefixed with ^ or ~ — that place text, barcodes, boxes and stored images on the label. A label opens with ^XA and closes with ^XZ.

The format is compact and deterministic, which suits warehousing and logistics, where millions of identical labels must come out with the right barcode every time. ZPL II is the widely used version and has become a de facto standard that rival brands emulate. The competing EPL was simpler but has effectively been retired in ZPL's favour.