A label needs a barcode to scan. When a product has none saved in Shopify, Stockroom can generate one - for the products in a print run, or for your whole catalog at once. The code is saved to the product in Shopify, so it works everywhere afterwards: scanning, stocktakes, receiving and printed labels.
Generate from the print dialog
If anything in the print run has no barcode, the print dialog says so just above the buttons - for example 3 products in this run have no barcode - with a Generate barcodes button beside it. Generating gives each of those products a barcode in Shopify and prints it on the label, so a shelf of unbarcoded stock becomes scannable in one pass.
Worth knowing before you use it:
Generated codes scan on any scanner and in Shopify POS with nothing to set up. Out of the box each one is a 13-digit EAN-13 starting with 20. If you want shorter codes, you can choose an 8-digit or 6-digit format - see Choosing the barcode format below.
The two EAN formats are internal codes, taken from a number range reserved for use inside a single business - which is what makes them safe, because no other company's product can ever carry the same code. Whichever format you pick, they are not licensed GTINs. Use them in your own store, stockroom and POS; for listing on Amazon or Google Shopping, or selling through a distributor, you need barcodes issued to you by GS1.
Only empty barcodes are filled. A product that already has one is left exactly as it is, so you can print a whole order without checking first.
The code is saved to the product in Shopify, not just printed on the label, so it is there the next time you scan that item into a delivery or a stock count.
Choosing the barcode format
Go to Settings > Labels > Generated barcodes and pick a Format. There are three, and the page shows you an example of the next code as you choose.
EAN-13 - 13 digits. The standard retail barcode, and what Stockroom uses unless you change it.
EAN-8 - 8 digits. A short retail barcode with the same protection as EAN-13, and about a third narrower. This is the one to pick for small labels like jewellery tags, where a full-length barcode has to print very fine to fit.
Short number - 6 digits. The shortest option and the easiest to read out or type in by hand. It is a plain number rather than a retail barcode, so it prints as a Code 128 - it scans anywhere, but short numbers are reserved to nobody, so one could clash with a code from an older system or a supplier's own label. Stockroom skips any code already in your catalog, but it cannot see labels it did not print.
If you are choosing for space, it is worth knowing that shorter is not always narrower: a 6-digit code and an 8-digit EAN-8 print at almost exactly the same width, so the real choice between them is whether you want a check digit or a code you can read aloud.
Changing the format never renumbers barcodes you already have - it only decides what the next ones look like. You can switch back and forth, and each format carries on from where it left off.
Generate for a whole catalog
If you are moving to Stockroom with a lot of unbarcoded stock, you do not have to work through it order by order. Go to Products, set the Barcodes filter to No barcode, and the page tells you how many are missing - for example 168 barcodes missing across 142 products. Generate barcodes then does the whole set.
It covers everything matching the filters you have on, not just the page you are looking at, so you can narrow it first - one vendor, or active products only - and generate for that group alone. Large catalogs keep running in the background: you can leave the page and come back, and the count carries on where it left off. Products that already have a barcode are skipped, so it is safe to run over your whole catalog.
The codes are the same internal EAN-13s described above - right for your own store and point of sale, not licensed GTINs for selling through a marketplace.
Good to know
Until a product has a barcode, its labels encode the SKU instead, so new products still scan - see Print barcode and price labels.
You can also add a barcode as you receive a delivery, from the cartons in front of you - see Receiving Inventory Against a Purchase Order.