Practical barcode knowledge from Marcus Rivera, former Amazon warehouse operations manager — 5 years on the receiving dock.
From someone who's scanned thousands. What a UPC actually is, who needs one, costs, and the GS1 prefix system explained clearly.
The practical difference, which market requires which format, and how to convert between them.
Why browser-based generators are the only safe option. What I test for: check digits, quiet zones, SVG quality.
Step-by-step: GS1 prefix, assigning product codes, generating images, and adding to Shopify inventory.
When to use each format. Practical comparison from warehouse and logistics experience.
Inkjet vs laser vs thermal, the DPI mistake, quiet zone requirements, and testing before mass printing.
GS1 explained without the corporate jargon. What it costs, who needs it, and the "$5 UPC" trap.
Exact dimensions, placement rules, and common compliance rejections from major retailers.
Built-in camera vs dedicated apps, what actually works, and when you still need a dedicated scanner.
Zebra vs Rollo vs Dymo. Real scan reliability data from 20+ printers across three warehouses.
FNSKU vs UPC, label size, placement rules. What an FBA receiving dock actually rejects.