If a marketplace has rejected one of your barcodes, or you're setting up Shopify product data for the first time, the fix usually traces back to one thing: the barcode wasn't built from a number block your business actually owns. That block is called a GS1 Company Prefix. This guide covers checking whether you already have one, getting one if you don't, and connecting it correctly inside Shopify.
Is this guide for you? This is for stores that manufacture, formulate, or otherwise own the products they sell. That's the kind of business a GS1 Company Prefix is designed for. If you resell or dropship other brands' products, you don't need your own prefix; you need the barcodes those brands already assigned. Assigning your own prefix to someone else's product creates the exact mismatch this guide is trying to help you avoid.
What Is a GS1 Company Prefix?
A GS1 Company Prefix is a block of numbers licensed to your business by GS1, the nonprofit standards body behind the barcodes on retail products worldwide. It's how own-brand sellers get valid, marketplace-recognised GTINs: every GTIN you assign starts with your prefix, which is how a marketplace confirms a barcode traces back to the company that actually makes the product rather than a reseller or a number picked at random.
How It Differs from a GTIN, UPC, and EAN
These terms get used loosely, and the mix-up causes real setup mistakes. A GS1 Company Prefix is the number block you are licensed. A GTIN (Global Trade Item Number) is the umbrella term for the full barcode number built from your prefix, a product reference you assign, and a check digit. UPC and EAN are regional names for a GTIN of a specific length: UPC is the 12-digit version used mainly in North America, EAN is the 13-digit version used mainly everywhere else. So a UPC and an EAN are both GTINs; a prefix is not a GTIN, it's what a GTIN is built from.
Why Prefix Length Varies (6-10 Digits)
Your prefix is between 6 and 10 digits, and the length is set by how many products it needs to cover, per GS1's own company prefix standard. A GS1 US prefix sized for 10 products uses more digits for the prefix and fewer for the product reference; a prefix sized for 100,000 products works the other way. GS1 UK prefixes follow the same logic and are recognisable because they all start with "50" .
Do You Already Have a GS1 Company Prefix?
Some merchants have a prefix and don't know it. Usually it's because whoever registered it left the company, or because it was set up years ago alongside a wholesale account. Check these before assuming you need to start over:
Your prefix is printed on the certificate issued at signup. If you can't find the physical copy, your national GS1 organisation can reissue proof of your membership.
The first several digits of any UPC or EAN you've shipped are your prefix. Cross-check it against a GS1 invoice, since a barcode a print shop generated without a real prefix won't hold up.
Search for a GS1 US, GS1 UK, or regional GS1 invoice. Annual renewals are easy to lose track of if one person set this up years ago and moved on.
If none of that turns anything up, you don't have one yet, and the next section covers getting one.
Company Prefix vs. a Single GTIN: Which Do You Need?
If you only need to identify a handful of products and don't expect to grow the line, GS1 US also sells individual GTINs without a full company prefix: a one-time $30 fee per GTIN, with no annual renewal . It's cheaper upfront, but each purchase is separate, with no room to assign more later. A company prefix costs more initially but lets you assign as many GTINs as its capacity allows, which is the better fit once you're past a first product or two. If you're planning more than one or two products, a prefix is usually worth the extra upfront cost.
How to Get a GS1 Company Prefix
You apply through your national GS1 organisation directly, not through Shopify and not through any app.
- Estimate how many products and variants you need to identify. Each size, colour, and bundle needs its own GTIN, so a small product line with several variants adds up faster than it looks.
- License a prefix sized to that number through your national GS1 organisation.
- Pay the membership fee and receive your certificate with your prefix printed on it.
- Start assigning GTINs from your prefix to your products.
Applying Through GS1 US
GS1 US runs this as a membership: you size your prefix to your catalog, and GS1 US Data Hub walks you through assigning your first GTINs once you're licensed .
Applying Through GS1 UK (and Other National GS1 Organisations)
GS1 UK membership works the same way and starts from £50 a year. Most other countries run an equivalent national GS1 member organisation with its own pricing. Search "[your country] GS1" if you're outside the US or UK.
Sizing Your Prefix to Your Catalog
Size for where your catalog is headed, not just where it is today. A smaller prefix is cheaper, but resizing later means a second application from scratch. If you're likely to add variants, colourways, or a second product line within a couple of years, size for that now rather than the exact SKU count you're carrying this quarter.
Membership Cost and Renewal
GS1 US prices a company prefix by how many products it covers, with a separate annual renewal on top of the initial fee. These figures come from the GS1 US store's company prefix page, as of August 2026:
| Product capacity | Initial fee | Annual renewal |
|---|---|---|
| Up to 10 | $250 | $50 |
| Up to 100 | $750 | $150 |
| Up to 1,000 | $2,500 | $500 |
| Up to 10,000 | $6,500 | $1,300 |
| Up to 100,000 | $10,500 | $2,100 |
Fees are non-refundable, so size deliberately rather than defaulting to the cheapest tier. GS1 UK membership works differently, starting from £50 a year rather than a separate initial-plus-renewal structure . Either way, budget for this as a recurring cost, not a one-time purchase. A lapsed membership can complicate re-verification if a marketplace re-checks your account later.
This is licensing the right to assign GTINs. It doesn't register a specific product with Amazon, Google, or any retailer. Each of those still needs the number entered on its own platform, which is the step covered next.
How to Connect Your GS1 Company Prefix in Shopify
Shopify has a barcode field on every product and variant, but it doesn't check whether what you type in is a real, validated GTIN. That gap is where most setup mistakes start: a number that looks right gets saved, and the problem doesn't surface until a marketplace rejects it weeks later.
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Add your prefix once, in GS1 Assistant's setup screen. This is the "Manage Your Company Prefixes" feature on the app's Free plan , and everything else depends on getting this step right.
Step 1 · The Add Company Prefix dialog -
Assign your own barcodes to products and variants from that prefix. The app checks format and check digit as you go, flagging anything that would fail a marketplace's own validation before it's published anywhere.
Step 2 · Pick the prefix, then Assign -
Run duplicate detection across your catalog. A common failure mode is two variants ending up with the same GTIN after a bulk import. That passes a basic format check but fails the moment a marketplace cross-references it.
Step 3 · GTIN Manager filtered to duplicates -
Confirm it worked. See "How to Confirm Your Setup Is Working" below. It's worth its own section rather than a quick note here.
Have a prefix? Assign your first 20 GTINs free
GS1 Assistant handles steps 1 to 3: the checking, assigning and duplicate detection. The prefix itself still comes from GS1; the app takes over from the moment you have one.
The free plan covers up to 20 GTINs, enough to test the setup on a first product line before committing. Paid plans start at $4.99 a month for up to 500 GTINs, or $11.99 a month for unlimited, both billed every 30 days .
Common Mistakes That Cause Marketplace Rejections Later
Most rejections that show up weeks or months after a product goes live trace back to one of these.
1. Reusing a GTIN Across Variants
Each size, colour, or bundle needs its own GTIN. A shared GTIN across variants is one of the more common reasons a listing gets flagged for a brand mismatch, because the marketplace sees the same number tied to what looks like two different products.
2. Skipping Duplicate Checks After a Bulk Import
Bulk product imports are the most common place duplicate GTINs sneak in, because a spreadsheet copy-paste error is invisible until something actually checks it.
3. Treating a Resold or Generated Number as Equivalent
A number that passes a check-digit test isn't the same as a number registered to your company. This is the root cause behind most GTIN rejections, and it only surfaces once a marketplace cross-references the prefix against its own records, which can be well after the listing first went live. Walmart Marketplace is the strictest of the three big channels here: it requires GTINs licensed to your brand and checks them against GS1's records at listing time, not later .
4. Amazon Flags a GTIN as Not Matching Your Brand
This is the sharpest version of the mismatch problem, because it doesn't just fail quietly. It can suspend an active listing. There are two different causes behind it, and they need different fixes.
The first is a wrong prefix: the GTIN traces back to a prefix registered to a different company than the one selling the product, which is exactly what a resold or non-GS1 barcode produces. The fix is assigning a GTIN from a prefix your own business actually owns.
The second is subtler, and it can hit a prefix you own outright. Amazon checks the GS1-registered company name against the brand name on your Amazon Brand Registry trademark, and a mismatch there (Amazon error 5461) triggers the same rejection even when the prefix itself is correctly licensed. "Smith Manufacturing Inc." on your GS1 registration and "Smith Home Products" on your Amazon listing is enough to trip it.
Either way, update the listing with the corrected number. If Amazon requests proof, provide your GS1 certificate to confirm the brand association.
How to Confirm Your Setup Is Working
Once GTINs are assigned, check Verified by GS1 status rather than assuming the setup is correct. Products assigned from a real, correctly licensed prefix show up as verified in GS1's own registry shortly after assignment; products built on an invalid or unregistered prefix don't.
Checking Verified by GS1 Status
GS1 Assistant surfaces this status per product, which is a faster check than waiting for a marketplace to reject something and working backward from there.
What to Do If a Product Isn't Verified
If a product isn't showing as verified and you're confident the prefix itself is correct, the more common cause is a formatting issue in how the individual GTIN was entered, not a problem with the prefix. Re-check the specific number against your GS1 membership records before assuming the whole setup is broken. GS1 Assistant flags the specific field that's failing, so you're not guessing which digit is wrong.
Frequently Asked Questions
How long is a GS1 Company Prefix?
Between 6 and 10 digits. The exact length depends on how many products it's sized to cover: a prefix licensed for 10 products uses more digits than one licensed for 100,000, since the two share a fixed total length with the product-reference portion.
Can I use a GS1 prefix from one country in a Shopify store based in another?
Yes. A GS1 Company Prefix identifies your company globally, not just in the country where you registered it. You apply through whichever national GS1 organisation covers where your business is legally based, and the resulting GTINs work on marketplaces worldwide.
What happens if I don't assign GTINs from my own prefix?
The barcode may scan and pass a basic check-digit test, but any marketplace that cross-references the GS1 registry will eventually flag the mismatch. On Amazon this surfaces as a listing rejection or suspension; in Google Merchant Center it shows up as an "invalid GTIN" item disapproval; Walmart Marketplace rejects unlicensed GTINs at listing time. Either way, it's worth fixing before a product goes live rather than after.
Is this different from buying resold or "cheap" barcodes online?
Yes. A bulk UPC reseller hands you numbers from someone else's prefix, so the marketplace's records show the product belonging to a different company than the one selling it. That mismatch is the single biggest cause of Amazon and Google Shopping GTIN rejections. If you sell your own products, licensing your own prefix is the version of this that holds up under a marketplace's validation.
Do I need a new prefix for a second product line or brand?
Not necessarily. One prefix can cover multiple product lines if it was sized with enough capacity. A second, entirely separate brand under a different legal entity is the more common reason to license a second prefix. Check with your national GS1 organisation if you're unsure which applies.
Is a GS1 barcode mandatory?
Not for selling in your own storefront; Shopify doesn't require one. It becomes effectively mandatory the moment you list on Amazon, Walmart Marketplace, Google Shopping, or most retail buyers, since they validate against the GS1 registry and reject numbers that don't check out.
Does printing the barcode on packaging require anything extra?
No. A valid GTIN prints the same way regardless of where it came from. Getting the number right and getting it onto a physical label are two separate problems; we cover the second one in our guide to Shopify barcode label apps.
Why doesn't my GTIN match my brand on Amazon?
Usually because the barcode wasn't assigned from a prefix your business actually owns, either a resold number or one generated rather than licensed. It can also happen with a correctly-owned prefix if your GS1-registered company name doesn't exactly match your Amazon Brand Registry name. Reassign the GTIN from your own prefix, correct the listing, and provide your GS1 certificate if Amazon asks for proof.
Does GS1 Sunrise 2027 mean I need new barcodes?
No. Sunrise 2027 is GS1's target for retail checkout systems to read 2D barcodes (QR-style codes) alongside the familiar 1D stripes, which aren't being retired . Your existing prefix and GTINs carry over unchanged, and a GS1 Digital Link QR code encodes the same GTIN you already own, with no second licence to buy.
Start Here, Not After a Rejection
Checking whether you already have a GS1 Company Prefix takes a few minutes. Getting one, if you don't, takes longer, but it's a one-time setup rather than something you redo per product. The part most guides skip is connecting it correctly inside Shopify before anything ships to a marketplace. That's the difference between finding a formatting mistake now and finding out about it from a rejection notice later.
If you're comparing tools for the Shopify side of this, our guide to Shopify barcode and GTIN apps covers that ground in more depth. If you already have a prefix and want to assign, validate, and check Verified by GS1 status without spreadsheets, try GS1 Assistant. The free plan covers your first 20 GTINs.