A SKU (stock-keeping unit) is an internal code your own systems assign - unlike a barcode, there's no external standard body for the format, so most of the actual work is deciding on a consistent pattern and then applying it to every product variant without typos or accidental collisions.

This generates SKUs from a template pattern, expands attribute lists like colour and size into every combination automatically, and flags duplicates before they reach your catalog.

When you'd use this

Setting up a new product line with variants: enter a pattern once (say, {BRAND}-{CAT:3}-{COLOR:3}-{SIZE}-{SEQ:4}), list the colour and size options, and get every SKU for the full variant matrix at once instead of typing each one by hand.

It's also worth running an existing SKU list through the collision check before a bulk import - two attribute values that abbreviate to the same three letters (say, "Forest Green" and "Fern Green" both truncating to a similar code) is the most common way duplicate SKUs slip through.

Common errors

A "duplicate" flag means two different attribute combinations produced the exact same SKU string - almost always because an abbreviation rule (like {COLOR:3}) truncated two different values down to the same characters. Widening that field's character count or picking less similar attribute names usually fixes it.

The "too long" warning exists because several marketplaces cap SKU length around 40 characters; a SKU that's fine internally can still get silently truncated or rejected on import elsewhere.

Frequently asked questions