1. 01Choose a barcode format and read the input rules shown under it.
2. 02Type the barcode content; after roughly 150 ms of debounce the page re-renders and validates it automatically.
3. 03Adjust the bar width (1–4 px), the height (30–160 px), the bar colour, the background colour, and whether the human-readable caption is shown.
4. 04Once validation passes, download PNG or SVG.

• CODE128 supports ASCII; CODE39 only supports uppercase letters, digits, space and - . $ / + %.
• EAN-13 takes 12 or 13 digits, EAN-8 takes 7 or 8, UPC-A takes 11 or 12 and ITF-14 takes 13 or 14; the shorter form is there to have the check digit generated.
• Bar width is 1–4 px and bar height 30–160 px; the canvas margin is fixed at 12, and the caption below can be switched off.
• PNG is a raster image and SVG is a vector text file; the tool cannot guarantee that a printer, a label size or a retail system will accept the result.
• What it does not do: it does not generate 2D codes such as QR or Data Matrix, and it neither applies to GS1 for a product code nor verifies ownership of one.

Barcode content, validation and rendering all happen locally in the browser; only the application's dependency code is loaded on demand, and no barcode data is sent to an external service.