How QR codes work
The QR code was created by Denso Wave in 1994 for tracking car parts and is now standardised as ISO/IEC 18004. The three large corner squares let it be read from any angle. Size is set by the version: version 1 is 21×21 modules and each step adds 4, up to 177×177 at version 40. Longer content means a denser code, so shortening the URL is the easiest way to make a small print scan reliably. One code holds up to 7,089 digits or about 2,950 bytes. Keep the standard 4-module quiet zone around the code, keep dark dots on a light background with strong contrast (inverted codes fail on some camera apps), and size the print at roughly a tenth of the scanning distance — at least 2 cm on a business card.
Wi-Fi and contact codes
A Wi-Fi QR is the string WIFI:T:WPA;S:name;P:password;;. Android and iPhone cameras recognise it and offer to join the network. Semicolons, commas, colons, quotes and backslashes must be escaped, which this tool does automatically. For a shop, create a separate guest network. Contact codes use vCard 3.0 so a scan opens "Add to contacts" with name, company, title, phone, email, website and address filled in.
Barcode numbers and what 880 means
A 13-digit retail barcode is an EAN-13 (GTIN-13). The first three digits are the prefix of the GS1 organisation that issued the company number — 880 is Korea. It does not indicate the country of manufacture. Company and item numbers follow, and the last digit is a check digit: weight the other digits 3,1,3,1… from the right, sum them, and pick the digit that rounds the total up to a multiple of 10. Real retail numbers must come from a GS1 membership (GS1 Korea in Korea); a made-up number can collide with another company's product. Books use ISBNs (978/979) instead. For labels used only inside one store or company, use CODE128 or the restricted-circulation prefixes 200–299.
Privacy — how your input is handled
Codes are generated in your browser. Wi-Fi passwords, contacts and barcode numbers are never stored or recorded; the generator library is downloaded once from this site, and we log only an anonymous usage count. The codes are static, so scans never pass through us.