QR Code Generator

A QR Code Generator turns a piece of text - a link, a WiFi password, a phone number, a contact card - into the square black-and-white matrix that any phone camera can read. The encoder takes your input, converts it to UTF-8 bytes, wraps it in Reed-Solomon error correction, and lays the result out as modules following the ISO/IEC 18004 standard. What you get back is a picture that carries data, readable by every scanner app on the planet.

This generator implements the full specification in the browser: versions 1 through 40, error correction levels L, M, Q, and H, automatic version selection, and penalty-scored mask selection so the resulting code is as easy to scan as possible. It encodes in byte mode with UTF-8, which means accented characters, non-Latin scripts, and emoji all survive the round trip intact.

Two things make it different from most free QR sites. First, the QR code never expires and never redirects: the data is baked into the image itself, not stored on someone else's server behind a tracking URL that can be switched off. Second, everything runs 100% in your browser - your WiFi password, your phone number, your private link is never uploaded, logged, or added to a scan-analytics dashboard.

Error correction and capacity trade against each other, and the right level depends on where the code will live. The highest level can survive around 30 per cent of the code being damaged or covered, which is what makes a logo in the centre possible, and it does that by spending capacity on redundancy, so the same data needs a denser grid. For a code printed on paper in good conditions, the lowest level is enough and scans faster. For something on a sticker, a vehicle, or anywhere it may be scuffed, go higher. Two practical points: the quiet zone, the blank margin around the code, is part of the specification and a code cropped tight to its edge often will not scan. And these are static codes, so the content is fixed at generation and a printed run cannot be redirected later.