Around 60% of UK merchants pick an ecommerce platform based on a marketing page, then spend the next three years paying for the mistake — in app subscriptions, transaction fees, and hours of manual stock work. The platform that looks slickest in a demo is rarely the one that still works when your catalogue has a thousand SKUs and half your sales come from Amazon and Google Shopping.
This guide is the checklist we wish someone had handed us. It's built from running our own online store and platform, Cartiva, in production.
Why UK merchants outgrow their first platform
The pattern never changes. You start on a simple builder, hit 50 products, and suddenly the essentials are missing: multiple sales channels, wholesale accounts, VAT-friendly reporting, or sane stock management. The fix is usually another app. Then another. Before long you're paying for 20 subscriptions and maintaining two tools that don't talk to each other, just so one sale can travel from a marketplace to your dashboard.
That's the real cost of a "cheap" platform — not the monthly fee, but the apps, the manual sync, and the time spent in spreadsheets. The point of a platform is to collapse that work into one place.
What to look for in a UK ecommerce platform
- A fast storefront on your own domain. Your shop needs to convert; what's under the hood doesn't matter if the store is slow. Look for a hosted storefront built with the same checkout, stock and orders as everything else.
- Payments that are actually built in. Cards, wallets, PayPal and buy-now-pay-later should be one integration, not three. If the platform quotes its card rate and Klarna and Amex rates up front, that's a good sign. Tokenised cards and PCI DSS Level 1 infrastructure mean your store typically qualifies for the lightest compliance (SAQ-A).
- An integrated page builder. Product pages, landing pages and blog posts should be editable without touching code — and without buying a separate page builder app.
- Sales channels and marketplaces. Amazon and eBay listings, plus shopping feeds for Google, Meta, Microsoft, Pinterest and Snapchat. Every order from every channel should land in the same dashboard, so stock stays synced.
- B2B and wholesale built in. If you might ever sell to companies — price lists, payment terms, invoicing — don't buy that later. Wholesale as a bolt-on app is how retail brands end up running two platforms.
- Honest inventory. Low-stock alerts, multiple locations, backorders and clear stock levels on the product page. "Honest stock levels" sounds basic until a platform makes you guess.
- A migration path, not a lock-in. You should be able to import your catalogue in a spreadsheet and export it any time. And an API — a real, versioned one — so you can build the bridges you'll need later.
The hidden costs most buyers miss
- App subscriptions. Count them. A $30 store with five $20 apps is a $130 store with five integration points that can break.
- Transaction stacking. Some platforms charge a transaction fee on top of the payment processor's fee. Look for a published card rate with no surcharge layered on top.
- Migration and downtime. Switching platforms is a project. A platform that offers free product imports and auto-detects your columns makes it a day, not a quarter.
Why we built Cartiva
Between our own brands and the client work we do, we've run stores on every major platform — from single-product side projects to operations shipping thousands of orders a week. Cartiva is the platform we wished we'd had: products, orders, customers and payments in one back office, with honest stock levels per size and colour, AI-powered natural-language search and recommendations, and free 30-day returns without the fine print. It's not hypothetical — you're looking at live proof right now. Our storefront, Cartiva, is a small catalogue of outerwear, footwear and everyday carry built and run on Cartiva itself, with every order, return and stock figure flowing through one dashboard.
The takeaway: judge a platform on the day your catalogue gets complex, not on the demo day. Explore our full product suite to see what we ship and run ourselves.