Overview
Expanding into new marketplaces has become a core part of many ecommerce growth strategies. Among the platforms gaining steady traction in the UK and beyond is OnBuy, a marketplace designed to connect third-party sellers with a growing base of online shoppers.
This guide explores how OnBuy works, its scale and trust profile, and how it fits into a multichannel ecommerce strategy in 2026.
What is OnBuy and how does it work
OnBuy is a British-born online marketplace, founded in 2016 and headquartered in the UK. It operates as a pure marketplace, meaning it does not stock or sell products itself, and therefore never competes with the sellers on its platform. Unlike some other major platforms, every sale on OnBuy goes to a third-party seller.
The platform lists over 35 million products across more than 6,000 categories, from consumer electronics and home furnishings to pet supplies and fashion. It is active across the UK and has expanded into 12 European countries, with EU markets in active growth.
OnBuy runs on a catalogue model, similar to Amazon. When a seller lists a product that shares a barcode with an existing catalogue entry, their offer is added alongside other sellers on that same listing, creating genuine price competition rather than duplicated listings. For products not yet in the catalogue, a new entry is created, though approval for brand-new items can take a few hours before the listing becomes visible.
Payments to sellers are processed through a range of payment options, and sellers can request a withdrawal of funds no later than 7 days after the end of the Delivery Timeframe (which ends upon delivery to the customer).
How many people use OnBuy
OnBuy attracts millions of monthly visitors and has built a growing base of both customers and sellers since its launch in 2016. The marketplace currently lists tens of millions of products across multiple categories, reflecting a steadily expanding catalogue and an increasingly active merchant ecosystem.
According to the Deloitte UK Technology Fast 50 programme, OnBuy has been recognised for its strong growth performance, ranking among the fastest-growing technology companies in the UK and EMEA region in recent years. The company was named a regional winner in 2021 and has continued to appear in subsequent Deloitte and FT1000-related growth rankings, highlighting its sustained expansion trajectory.
OnBuy also reports strong seller adoption, with thousands of retailers already active on the platform and new merchants joining regularly as part of its ongoing marketplace expansion.
Can OnBuy be trusted
OnBuy is a legitimate, registered UK business that pays UK taxes and VAT. It has accumulated over 127,000 reviews on Trustpilot, where it holds a consistently positive overall rating. The majority of reviewers report positive purchasing experiences, citing competitive pricing and wide product availability.
As with any large marketplace, individual seller performance varies, and negative reviews typically concern specific sellers rather than the platform itself. OnBuy enforces seller standards and requires businesses to be legally registered (UK or international) before they can list. Stripe handles all payment processing, which adds a layer of financial protection for both buyers and sellers.
From a seller perspective, trustworthiness also comes from structural transparency: fee structures are published clearly, there are no hidden transaction costs, and the platform does not place its own competing products in the catalogue.
Is it free to sell on OnBuy
Selling on OnBuy is not entirely free, as the platform operates on a subscription-based model combined with category-based commission fees. However, it does not charge listing fees, and sellers are not required to pay additional transaction fees beyond the standard marketplace commission.
OnBuy subscriptions typically run on a rolling basis, allowing sellers to manage or adjust their plan depending on their business needs. Pricing structures and commission rates vary by category and are defined within the seller agreement.
What are the benefits of using OnBuy
OnBuy operates as a third-party marketplace without selling its own private-label products. This means sellers are not competing against a platform-owned inventory, but instead against other independent merchants offering the same catalogue products. Product visibility is therefore driven by pricing, fulfilment, and seller performance rather than internal retail competition.
Key benefits include:
- Flexible and scalable model
Commission-based structure combined with optional subscription pricing, with no upfront listing fees. Category-dependent commissions let sellers plan margins based on product type before listing. - Strong UK marketplace reach
Access to a growing UK-based customer base across a wide range of categories. Catalogue system groups identical products using GTINs (EAN, UPC, ISBN), consolidating demand into single product pages instead of fragmented listings. - Centralised seller operations
Integrated dashboard handles payments, order management, fulfilment tracking, and customer communication. Designed to keep core marketplace workflows in one system. - Structured product condition support
Allows listings for both new and refurbished items, with defined grading standards for refurbished goods. Useful for sellers operating in secondary or reconditioned markets.
Why should sellers consider OnBuy as part of their sales strategy
For multichannel sellers already operating on platforms such as Amazon, eBay, Shopify, Etsy, TikTok and WooCommerce, OnBuy can function as a complementary sales channel rather than a replacement. The key value lies in diversification: adding another marketplace helps reduce dependency on a single ecosystem and spreads sales performance across multiple demand sources.
Unlike some larger marketplaces where competition is heavily influenced by internal retail dynamics or algorithmic visibility constraints, OnBuy’s catalogue-based structure relies primarily on product data quality, pricing, fulfilment, and seller performance. This makes it particularly relevant for sellers who already maintain structured catalogues and can easily adapt GTIN-based listings.
For businesses already managing inventory across multiple channels, OnBuy does not require a different operational model, but instead extends existing product distribution into an additional marketplace environment. This allows sellers to reuse existing listings, expand reach into a UK-focused audience, and test incremental demand without restructuring their core ecommerce setup.
In this context, tools like Nembol become relevant for sellers looking to expand efficiently. By connecting OnBuy to Nembol, merchants can publish, sync, edit and import their catalogue alongside other marketplaces, keeping product data consistent across channels without duplicating manual operations.
How can sellers manage OnBuy alongside other marketplaces with Nembol
Nembol enables sellers to manage OnBuy as part of a unified multichannel workflow alongside platforms.
Before publishing products to OnBuy, Nembol ensures that all required listing conditions are met. Each product must include:
- A valid GTIN (EAN-13, UPC-12, or ISBN-10), which is automatically validated to prevent submission errors
- A product category, suggested by Nembol through AI-based matching against OnBuy’s full category structure, with the option for manual adjustment
- A delivery template, which is automatically applied from the seller’s default settings or requested during publishing if none is available.
Once listings are published, Nembol continuously synchronises catalogue data across all connected channels. Every time an order is received on any marketplace, stock is automatically updated across all other channels according to the user’s synchronization settings.
Products can be managed centrally. Sellers can update product information, pricing, and inventory directly within the platform, with changes automatically reflected across all connected sales channels, including OnBuy. This ensures that catalogue updates remain consistent without requiring manual edits on each marketplace.
Nembol also allows sellers to apply pricing rules to automate price adjustments across channels, helping maintain controlled and consistent pricing strategies depending on margins, marketplaces, or specific business rules.
For OnBuy multi-variant products, sellers can manage variations in a structured way and assign specific attributes to each variant. This includes the ability to add and manage variant-specific images directly within Nembol, ensuring that product data is automatically adapted to each marketplace’s requirements at publish time.
Currently, OnBuy integration in Nembol supports only the UK marketplace. With the Enterprise+ plan, sellers can connect up to 10 separate OnBuy accounts within a single Nembol account, enabling centralized management of multiple storefronts from one interface.