What encoding does this use?

It produces a spec-correct Code 128 barcode following ISO/IEC 15417. It auto-selects Code Set C for runs of digits (two digits per symbol) and Code Set B for everything else, then appends a weighted modulo-103 check digit and the stop pattern.

Will the barcode actually scan correctly?

Yes — the bar and space widths come directly from the standard Code 128 pattern table and include the mandatory check digit and quiet zones, so any compliant scanner can read it. For best results print at a module width of 2px or more and keep the white margins.

Is my text uploaded anywhere?

No. The barcode is drawn entirely in your browser using a canvas. Your text and the generated image never leave your device.

Code 128 Barcode Generator

Code 128 barcode generator

Turn any text or number into a scannable Code 128 barcode and download it as a PNG. Code 128 is the high-density linear barcode used on shipping labels, retail packaging, asset tags and internal documents because it can encode the full set of ASCII characters in a compact space.

The generator follows the ISO/IEC 15417 specification: it automatically picks Code Set C for runs of digits (packing two digits per symbol) and Code Set B for letters and symbols, then appends the required weighted modulo-103 check digit and stop pattern. Quiet zones are added on both sides so scanners can lock on.

It is privacy-first: the barcode is rendered locally on a canvas and nothing — not your text, not the image — is ever uploaded.