Selling on OnBuy from Shopify: A Complete Guide for UK Sellers

Everything UK Shopify sellers need to know about selling on OnBuy: requirements, fees, setup, and daily management.

Selling on OnBuy from Shopify gives UK sellers access to a fast-growing marketplace without doubling their workload. OnBuy processed over 150 million pounds in sales in 2024, charges lower fees than Amazon, and doesn’t compete with sellers using its own branded products. Here’s everything you need to set up and start selling.

TL;DR: OnBuy is one of the fastest-growing marketplaces in the UK, and connecting it to your Shopify store gives you access to millions of new customers without rebuilding your product catalog from scratch. Our Shopify OnBuy integration handles the heavy lifting: syncing products, importing orders, and keeping inventory in check across both platforms.

What Is OnBuy, and Why Should You Care?

OnBuy is a UK-born marketplace that processed over 150 million pounds in sales in 2024. It lists more than 36 million products from over 11,000 active sellers, and it pulls in roughly 3.5 million monthly visits. Those are real numbers from a platform that’s only been around since 2016.

The pitch to sellers is straightforward: lower fees than Amazon, no competing with the marketplace’s own brands, and organic product rankings instead of pay-per-click ad auctions. Whether that pitch holds up under scrutiny is something we cover in our OnBuy vs Amazon comparison. Short version: it does, with caveats.

OnBuy by the Numbers

Before diving into the how-to, here’s what you’re working with:

  • Sales growth: 50% year-over-year increase in early 2025, with 33 million pounds in sales from January to April alone
  • Repeat purchases: Over 50% of UK customers come back to buy again
  • EU expansion: 12 European countries now live, with 308% sales growth in those markets during beta
  • Revenue growth: 224% annual revenue increase reported in 2024

These numbers matter because they signal where the marketplace is heading. OnBuy isn’t a side project. They’re targeting 1 billion pounds in total GMV within three years, and they’ve expanded into Europe to get there.

What You Need Before You Start

OnBuy has specific seller requirements. Don’t skip these, or your application will get rejected:

  • A registered business with valid documentation (UK or international)
  • At least 50 buyer reviews from the past 12 months on an existing selling platform, with 90% rated 4 or 5 stars
  • GTINs or barcodes for every product you plan to list
  • VAT registration details (if applicable)
  • Valid photo ID and proof of address dated within the last 3 months
  • A UK bank account or a Payoneer/WorldFirst account for payouts
  • A returns solution for each country you sell in

That review requirement catches some sellers off guard. If you’re brand new to online selling with zero marketplace history, OnBuy isn’t your first stop. Build a track record on Shopify or another channel first.

OnBuy Fees: What You’ll Actually Pay

OnBuy runs on a subscription plus commission model. Three plans are available:

PlanMonthly CostBest For
Standard25 pounds/month + VATSellers starting out on OnBuy
Partner69 pounds/month + VATGrowing businesses wanting priority support
Professional249 pounds/month + VATHigh-volume sellers

On top of the subscription, OnBuy charges category-based commissions ranging from 5% to 15%. Most product categories fall between 5% and 9%. Fashion and books tend to sit at the higher end around 15%, while consumer electronics typically lands around 7%.

There are no listing fees and no per-item charges. You pay the subscription and commission on actual sales. That’s it.

Connecting Shopify to OnBuy

This is where the OnBuy Shopify integration comes in. Without an integration tool, you’d need to manually recreate every product listing on OnBuy, copy orders back into Shopify, and update stock levels by hand across both platforms. That works for 10 products. It falls apart at 100.

An integration app bridges the two platforms. Your Shopify store stays your single source of truth for product data, pricing, and inventory. The integration syncs everything automatically: product details push to OnBuy, orders flow back to Shopify, and stock levels update in real time.

Managing Your OnBuy Business Day to Day

Products

Your Shopify product catalog maps to OnBuy listings. Title, description, images, pricing, and variants all sync over. When you update a price in Shopify, it updates on OnBuy. When you add a new product, it appears on OnBuy. No double entry.

Orders

When a customer buys on OnBuy, the order appears in your Shopify admin. You fulfill it the same way you fulfill any other Shopify order: pick, pack, ship, and add tracking. The tracking information syncs back to OnBuy so customers can follow their delivery. Read more about how this works in our guide to OnBuy order sync.

Inventory

This one’s critical. Nothing kills marketplace seller ratings faster than overselling. When a unit sells on Shopify, the stock count updates on OnBuy. When a unit sells on OnBuy, it updates in Shopify. We go deep on this topic in our stock sync guide.

Tips for Selling on OnBuy

Competitive pricing wins. OnBuy doesn’t have sponsored listings or ads. Products rank based on price, seller rating, and delivery options. If your price is right and your fulfillment is fast, you’ll get visibility without spending extra on advertising.

GTINs are non-negotiable. Every product needs a valid barcode. If your Shopify products don’t have barcodes assigned, sort that out before attempting to list on OnBuy.

Fast dispatch matters. OnBuy customers expect quick shipping. Keep your dispatch times honest and your tracking information accurate. Your seller rating depends on it.

Think about Europe. OnBuy is now live in 12 EU countries. If you already ship internationally, this opens a significant new customer base with minimal extra effort. Our article on selling on OnBuy Europe covers what’s involved.

Is OnBuy Worth It for Shopify Sellers?

If you already run a Shopify store with decent product data, barcodes, and fulfillment processes in place, adding OnBuy as a sales channel is relatively low-friction. The fees are competitive, the marketplace is growing, and you’re not competing against the platform itself for sales.

The integration makes it practical. Without automated sync, managing a second marketplace becomes a full-time job. With it, OnBuy becomes another tab in your Shopify admin rather than a separate business to run.

Ready to connect your store? Check out the Shopify OnBuy integration to get started.

Frequently Asked Questions: Selling on OnBuy from Shopify