Overview
Luminous can generate the next unused barcode for a SKU on demand, or automatically assign one whenever you create a SKU that has a blank barcode field. Three formats are supported:
| Format | Length | Check digit | When to use |
|---|---|---|---|
| UPC-A | 12 digits | GS1 Mod-10 | Standard US retail GTINs (requires GS1 company prefix) |
| EAN-13 | 13 digits | GS1 Mod-10 | International retail GTINs (requires GS1 company prefix) |
| Custom | You choose | None | Proprietary or internal warehouse sequences that do not follow GS1 rules |
Only admins can edit the barcode generation settings. Non-admin users can still click Generate to consume the next code once an admin has configured the setup.
Step 1 — Open the setup dialog
- Open or create a SKU.
- Find the UPC field on the SKU form.
- Click Set up UPC generation (shown when barcode generation has never been configured) or the gear / settings icon next to the field if it has been configured before.
- The Set up UPC / barcode generation dialog opens.
Step 2 — Enter your prefix
You need at least one prefix field filled in:
- GS1 company prefix — Your official GS1 manufacturer number (7–10 digits). Also used for SSCC carton labels. Leave blank if you only use custom internal barcodes.
- Barcode / GTIN prefix — A separate, shorter prefix used only for product barcodes (4–11 digits). Leave blank to reuse the GS1 company prefix. Use this field when:
- Your GS1 company prefix is too long to leave room for enough item-reference digits in UPC-A format.
- You are using custom internal barcodes and the prefix is not a GS1 number (e.g.
100000).
If both are filled in, the Barcode / GTIN prefix takes priority for product barcode generation.
Step 3 — Choose a format
Select from the Format dropdown:
- UPC-A (12 digits, GS1 check digit) — Luminous appends a GS1 Mod-10 check digit to your prefix + item reference. The total is always 12 digits.
- EAN-13 (13 digits, GS1 check digit) — Same as UPC-A but 13 digits total.
- Custom (fixed width, no check digit) — Luminous concatenates your prefix with a zero-padded item reference. No check digit is added. You control the total length.
The capacity preview line below the dropdown updates in real time and shows how many item-reference digits are available and how many SKUs your prefix + format combination can support.
Custom format only — set item reference digits
When Custom is selected, an Item reference digits field appears. Enter a number between 1 and 12 to set how many digits follow your prefix. For example, prefix 100000 (6 digits) + 5 item-reference digits = 11-digit barcodes with a capacity of 100,000 SKUs.
Step 4 — Set the starting number
The Next item reference field controls where the counter starts (default: 1).
- Type a number manually if you have already issued some barcodes and want to continue from a specific point.
- Click Scan catalog to let Luminous automatically find the highest item reference already assigned under your configured prefix and set the counter to the next value. Use this when migrating from a manual or imported barcode list to avoid reissuing existing codes.
The Next to assign (preview) line shows exactly what the next barcode will look like before you commit.
Step 5 — Enable auto-assign (optional)
Check Auto-assign when UPC is blank on create to have Luminous automatically fill the barcode field whenever a new SKU or variant is saved without a barcode. This happens in the same database transaction as the SKU create, so the barcode is never left blank if the counter has capacity.
Leave this unchecked if you want to assign barcodes manually or only on demand.
Step 6 — Save
Two save options are available:
- Save settings — Saves your configuration without generating a barcode for the SKU you are currently editing.
- Save and generate for this SKU — Saves your configuration AND immediately assigns the next unused barcode to the open SKU.
Generating a barcode on an existing SKU
Once the setup is complete, the UPC field on any SKU form shows a Generate button. Clicking it consumes the next unused code from the sequence and fills the field. If the code would collide with one already on another SKU, Luminous automatically skips it and tries the next one.
Notes and limitations
- EPC / RFID serials (for RFID-tag workflows) are only available for GS1 formats (UPC-A or EAN-13). Custom fixed-width barcodes cannot be used with EPC serial allocation.
- The counter never goes backward. If you abandon the SKU form after the dialog allocates a code but before you save, a gap in the sequence is expected and harmless.
- Barcode generation capacity is shown in the setup dialog. When the counter reaches the maximum for your prefix/format combination, generation will stop with an error — increase the item-reference digit count or change your prefix before that happens.
- Admins can reopen the setup dialog at any time to change the format, prefix, or starting number. Changing the format after codes have already been issued will cause the counter to continue from wherever it left off, but new codes will follow the new format — review your catalog before switching formats mid-stream.