QR error correction is a real trade-off: level H recovers from 30% damage but needs a denser code in the same space. Generate the same payload at all four levels and see how much the module size changes.
What you can control
- Five payload types, including the Wi-Fi and vCard formats that phones recognise natively.
- Four error-correction levels, so you can compare density before printing anything.
- Five symbologies covering both 2D codes and the linear barcodes still used in retail.
- Custom payloads take any string, for testing what happens when a code carries far more data than expected.
What this is not
Image URLs point at third-party rendering services. For production, generate codes locally — a checkout page that depends on an external service to draw a barcode has an outage waiting.
Questions
Are these QR codes actually scannable?
Yes. The rendering service produces a real, standards-compliant code, so your phone will read the payload.
Which error-correction level should I use?
M for anything on screen. H only when the code will be printed on something that gets handled, scuffed or partly covered by a logo.
What does the Wi-Fi payload do?
Encodes a network name, password and security type in the format phones recognise. Scanning it offers to join the network directly.