Stop retyping product data. Push your Shopify catalog to OnBuy automatically with synced listings and variants.
If you want to list Shopify products on OnBuy without spending hours on manual data entry, this guide explains how automated integration works and why it makes a significant difference for both initial setup and ongoing operations.
TL;DR: Manually recreating your Shopify product catalog on OnBuy means retyping titles, descriptions, prices, and variant details for every single product. With hundreds of SKUs, that’s days of work and a guaranteed source of errors. A Shopify OnBuy integration pushes your existing product data to OnBuy automatically.
Your Shopify store has 400 products. Each product has a title, description, 4-5 images, pricing, weight, and a barcode. Some have variants: sizes, colours, materials. That’s easily 1,200 individual SKUs with unique prices and stock levels.
Now you want to sell on OnBuy. Without automation, here’s your to-do list:
That’s not a task. That’s a punishment. And the real problem isn’t even the initial listing. It’s what happens next.
Products change. Prices go up. Descriptions get rewritten. New images replace old ones. Variants get added or discontinued. Every time you update something in Shopify, you need to remember to make the same change on OnBuy.
Forget to update a price on OnBuy after changing it in Shopify? You’re now selling at the wrong margin. Forget to mark a variant as out of stock? You’ll oversell and have to cancel the order, which damages your seller rating.
Manual listing isn’t just slow at the start. It creates an ongoing operational burden that grows with every product you add.
OnBuy listings require specific data fields. Here’s what maps from your Shopify catalog:
| OnBuy Field | Shopify Source | Notes |
|---|---|---|
| Product title | Product title | Direct mapping |
| Description | Product description (HTML) | OnBuy accepts HTML formatting |
| GTIN/Barcode | Variant barcode | Required. OnBuy won’t list without it |
| Price | Variant price | Can be synced or set independently |
| Stock quantity | Inventory level | Should update in real time |
| Images | Product images | Multiple images supported |
| Variants | Shopify variants | Size, colour, etc. |
| Weight | Variant weight | Used for shipping estimates |
Most of this data already lives in your Shopify admin. The question is how to get it across to OnBuy without retyping it.
This trips up more sellers than anything else. OnBuy requires a valid GTIN (barcode) for every product listing. No barcode, no listing. There’s no workaround.
If your Shopify products already have barcodes assigned (EAN-13, UPC, or ISBN), you’re set. The integration uses these to create and match OnBuy listings.
If your products don’t have barcodes, you’ll need to add them before listing on OnBuy. This is a hard requirement from the marketplace, not a limitation of any integration tool. Check your Shopify product pages: the barcode field is under each variant in the inventory section. Our complete seller guide covers all OnBuy requirements in detail.
An OnBuy Shopify integration replaces the entire manual process. Here’s the flow:
Step 4 is the part that matters long-term. The initial listing is a one-time effort either way. Keeping two platforms in sync forever is where automation pays for itself.
Variants are where manual listing really breaks down. A t-shirt in 4 sizes and 3 colours is 12 variants. Each needs its own barcode, price, and stock count on OnBuy. A shoe in 8 sizes is 8 variants. Multiply that across your catalog and you’re looking at thousands of individual data points.
An integration handles variant mapping automatically. Each Shopify variant with a barcode creates a corresponding OnBuy listing entry. Stock levels sync at the variant level, so selling out of “Medium / Black” on Shopify immediately shows that specific variant as unavailable on OnBuy, while other sizes and colours stay live.
Even if you decide to list manually (maybe you only have 15 products), doing it product by product through OnBuy’s seller panel is slow. OnBuy does support CSV uploads for bulk listing, which is faster than manual entry but still requires you to format a spreadsheet, map columns correctly, and re-export every time something changes.
The middle ground: CSV export from Shopify, reformat for OnBuy, upload. It works for the initial push. It falls apart for ongoing updates because you’d need to re-export and re-upload every time you change a price or add a product. That’s not sync. That’s a recurring export job.
A direct integration skips the spreadsheet entirely. Shopify is the source. OnBuy gets the data. Changes flow automatically.
If you’ve already listed some products on OnBuy manually, an integration can match them to your Shopify catalog using barcodes. The GTIN is the unique identifier on both platforms. When the integration sees a Shopify product with the same barcode as an existing OnBuy listing, it links them instead of creating a duplicate.
This means you don’t have to start from scratch even if you’ve already done some manual work. The integration picks up where you left off.
Product listing is just one piece of selling on OnBuy. Once products are live, you need order sync to pull OnBuy sales into Shopify and inventory sync to prevent overselling. All three work together: products go out, orders come in, stock stays accurate.
If you’re also considering which marketplace to start with, our OnBuy vs Amazon comparison breaks down fees, policies, and trade-offs. And if you’re interested in reaching European customers, OnBuy is now live in 12 EU countries.
Ready to skip the manual work? Check out the Shopify OnBuy integration.
The easiest way to list Shopify products on OnBuy is by using a Shopify OnBuy integration app. The app connects your Shopify store to OnBuy, maps your product fields (title, description, price, barcode, images, and variants) to the OnBuy format, and pushes listings automatically. Once connected, any product update in Shopify syncs to OnBuy without manual re-entry. You select which products to list, and the app handles all data transfer and ongoing syncing in real time.
Yes, OnBuy requires a valid GTIN (barcode): EAN-13, UPC, or ISBN – for every product listing. This is a hard marketplace requirement, not a limitation of the integration tool. If your Shopify products already have barcodes assigned to each variant, you’re ready to list. If not, you’ll need to source and add barcodes before you can create listings on OnBuy. The barcode field in Shopify is found under each variant in the Inventory section.
OnBuy does not officially support dropshipping in its standard terms. All listed products must be in stock and available for dispatch within 3 working days. Sellers are expected to hold or have direct access to the inventory they list. If you use a supplier who ships on your behalf, you need to ensure reliable fulfilment and accurate stock levels, as overselling on OnBuy damages your seller rating and can lead to account suspension.
Yes, for many Shopify sellers OnBuy is worth considering. OnBuy attracts over 4 million monthly UK shoppers, has lower seller fees than Amazon (typically 5–9% commission), and has less competition on most product categories. If your products already have barcodes and you want to reach more UK buyers without building a new audience from scratch, OnBuy is a legitimate multichannel expansion. The main requirement is having products that meet OnBuy’s listing criteria, particularly the GTIN/barcode requirement.
A Shopify OnBuy integration syncs inventory in real time. When a product sells on OnBuy, the stock count in Shopify decreases. When a sale happens on Shopify, OnBuy’s inventory updates automatically. This prevents overselling, one of the most common problems when managing multiple sales channels manually. Inventory sync operates at the variant level, so selling out of one size or colour only affects that specific variant on OnBuy, while others remain listed and available.
Yes, you can list products on OnBuy manually through their seller panel, or upload them via a CSV file. Manual listing works for small catalogues (fewer than 20 products), but becomes impractical at scale. CSV uploads speed up the initial push but require ongoing re-exports every time a product changes. Neither method syncs automatically. If your Shopify price or stock changes, you have to update OnBuy separately. An integration app automates both the initial listing and ongoing syncs, making it far more efficient for most sellers.
If you already have products listed on OnBuy manually, a Shopify integration can match them to your Shopify catalogue using product barcodes (GTINs). When the integration finds a Shopify product with the same barcode as an existing OnBuy listing, it links them instead of creating a duplicate. This means you do not lose your listing history or reviews, and your existing OnBuy presence transitions into an automated setup without starting from scratch.
Getting started typically takes a few days. First, you register as an OnBuy seller and wait for account approval, which usually takes 1–3 business days. Once approved, you install a Shopify OnBuy integration app, connect your store, configure product mappings, and push your listings. Products can go live on OnBuy within hours of being submitted, although OnBuy may take up to 24 hours to review and publish new listings. Having barcodes already set up in Shopify speeds up the entire process significantly.
OnBuy charges three types of fees: a monthly subscription fee (currently £19/month for the standard plan), a commission fee per sale (typically 5–9% depending on product category), and a payment processing fee (1.9–2.9% per transaction). There are no listing fees. You only pay when you sell. The integration app itself may also have a monthly cost, depending on which tool you use. These fees are separate from Shopify’s own subscription and transaction fees, so factor in both when calculating your margins.
All products on OnBuy come from third-party sellers. OnBuy does not sell its own products. Unlike Amazon, which sells both its own inventory and marketplace items, OnBuy is a pure marketplace where retailers and brands list their own stock. Sellers include independent UK retailers, Shopify store owners, wholesalers, and manufacturers. Products cover categories including home and garden, electronics, toys, health and beauty, sports, and tools.
Shopify variants such as sizes, colours, and materials sync to OnBuy as individual product entries, each with their own barcode, price, and stock level. Every variant needs a unique GTIN barcode for OnBuy to accept it. When a specific variant sells out, for example Medium in Blue, the integration updates that variant stock to zero on OnBuy while other variants remain available. This prevents overselling at the variant level, which is especially important for apparel and footwear sellers with large SKU counts.