Which Brands Does a Competitor Carry? Read the Vendor Field

A customer emails you about a jacket you don't stock. It's from a label you've never heard of, and the store down the road apparently has the whole range. You go and look, and sure enough, they've got about a dozen products from that brand. Now you want to know how long they've carried it and what else they've added since you last looked.

Do you carry this brand? The other shop has it in every color.

If you run a multi-brand Shopify store, you've probably heard some version of that line. You don't have to wait for customers to tell you. A Shopify store's public catalog already lists the brand behind every product, and with a bit of counting you can see a competitor's brand mix, how it changes over time, and where it overlaps with yours.

Where the brand list hides in a Shopify catalog

Every product in a Shopify store has a vendor field. In the admin it's usually filled with the brand or the supplier name, and it shows up in the public JSON feed that every store exposes at /products.json. If you haven't used that feed before, our guide to /products.json covers the basics: what's in it and how paging works.

For this job you only need three fields per product:

• vendor: the brand or supplier,
• product_type: the category the store assigned,
• published_at: when the product went live.

That's enough to answer most brand questions. The feed only shows products published to the online store, so anything hidden or in draft won't be there.

Counting products per brand in ten minutes

Open /products.json?limit=250 on the competitor's domain, then add &page=2, &page=3 and so on until a page comes back empty. Paste the results into a spreadsheet, or save them as files if you're comfortable with a small script. Then count products per vendor.

Here's a typical result for a small outdoor store with 412 products:

1. Brand A: 96 products
2. Brand B: 71 products
3. The store's own label: 58 products
4. Brand C: 23 products
5. Eleven smaller brands sharing the remaining 164 products

Brand A and Brand B make up 167 products, about 40% of the catalog, so most of this competitor's business sits with those two brands. If you stock either of those brands too, you're selling the same products to the same people, and price is where you'll feel it. If they have a 58-product house label, part of their range can't be compared with yours at all.

Write the date next to the count. A single count only becomes useful once you have a second one to compare it with.

Reading the shift between two counts

Run the same count a few months later and put the two side by side. Say the June count for the same store shows a new vendor, Brand D, with 14 products, while Brand C has dropped from 23 to 4.

Those two numbers mean different things. A new brand with 14 products in one go is a commitment: a store doesn't list that much from a label it's only testing. Look at the published_at dates. If they all landed in the same week, it was a planned launch. You can read more about this pattern in reading a competitor's launch cadence.

A brand shrinking from 23 products to 4 is usually a wind-down. The store is selling out what's left and not reordering. Sometimes the brand ended the account, sometimes margins were poor. You can't know which from the feed, but you know the shelf is being cleared. What a competitor's removed products tell you goes deeper on telling a real exit apart from a short stockout.

The new brand tells you where the competitor thinks demand is going. The fading brand may leave customers looking for a new place to buy it.

When the vendor field lies

Store staff type the vendor field by hand, so expect some mess:

• The same brand spelled two ways, like "Brand A" and "BrandA Outdoor". Merge them before you count.
• Stores that sell only their own products often put the store name in every vendor field, so the count tells you nothing.
• Some stores put the supplier or distributor there instead of the brand, which can lump several labels together.
• Bundles and gift cards turn up as products with odd vendors. Leave them out.

So check the top results against the product titles. If the vendor list looks strange, filter by product_type instead and count brands only within the category you care about.

Deciding what to stock (and what to stop chasing)

Shared brands are where price comparisons happen. For those, you need to watch the competitor's prices on the exact same products, and if their pack sizes differ from yours, compare unit prices rather than sticker prices. Brands only you carry are the reason some customers buy from you and not from them. Keep them in stock and make sure your product pages say clearly that you have them.

A brand the competitor just added is worth a closer look, but don't copy it on reflex. Check whether your customers have asked for it, and whether the brand would sell to you at all. A brand the competitor is dropping deserves a look too. If customers liked it, they'll need somewhere else to buy it, and that could be you.

If you'd rather not page through JSON every quarter, StoreSentry watches a competitor's catalog and puts new and removed products in a daily or weekly digest, so a run of launches from one label is easy to notice. The brand count itself is still a spreadsheet job. For a quick one-off look at any store, the free store checker shows catalog size and the newest launches without signup.