Barcode Generator creates a scannable barcode from text or numbers in several common formats, with the right length and character validation for each one.
CODE128 is the most flexible, since it accepts any text or numbers and is widely supported. EAN-13 and UPC-A are the formats used on retail products specifically, and have exact length and check-digit requirements.
Those formats require an exact digit count (12 or 13 digits for EAN-13, 11 or 12 for UPC-A). The validation message tells you exactly what's expected for the format you picked.
No. The barcode is rendered entirely in your browser using an open-source barcode library. Nothing is sent to a server.