Supporting 14 barcode symbologies taught me that QR won but legacy won't die

I added support for code128, EAN-13, ISBN, GS1-128 and a dozen other symbologies to my QR generator, fully expecting everyone to just use QR codes. The request logs say otherwise — roughly half the traffic is still EAN-13 for retail packaging and code128 for shipping labels.

Each 1D symbology has its own checksum algorithm, allowed character set, and quiet-zone rules. Getting code39 wrong means a scanner reads plausible garbage; getting QR wrong means it reads nothing at all. I ended up spending more time debugging the boring legacy formats than the shiny QR spec, because those formats are where the real-world edge cases live.

If you're building anything that prints labels or scans physical goods, don't assume QR has replaced everything. The 1D barcodes are still the workhorses of logistics and retail, and they fail in weirder ways than QR ever will. I wrapped all of them into one endpoint at https://x402.freeq.one/tools/qr_generator.html