Most new online stores should start on an established e-commerce platform and only go custom when the business outgrows it. Custom e-commerce pays off when the buying experience is unusual, the catalogue or pricing logic is complex, integrations with existing systems are deep, or platform fees and limits are shaping the business. A custom storefront on top of a commerce backend costs $50,000 to $150,000 (€44,000 to €130,000, £37,000 to £110,000). A fully custom platform with catalogue, checkout and integrations costs $150,000 to $400,000 (€130,000 to €350,000, £110,000 to £295,000) and takes 5 to 9 months.
Prices are in US dollars. Euro and pound figures in parentheses are approximate, rounded conversions. Quotes are issued in the currency of your contract.
E-commerce is the one industry where the honest first advice is often "do not build". Established platforms are excellent for standard stores, and building a standard store from scratch wastes money. Custom e-commerce earns its cost in specific situations. This guide helps you tell which situation you are in, and what to build if it is the custom one.
Should you build at all?
| Use an established platform if | Go custom if |
|---|---|
| You sell standard products in a standard way | The buying experience is unusual: configurators, subscriptions with complex rules, quotes, made-to-order |
| The catalogue is simple and pricing is per item | Pricing depends on customer, volume, contract, region or time, as in most B2B |
| You are validating whether the products sell | The products sell and the platform is now the constraint |
| Standard integrations with payments, shipping and accounting are enough | You must integrate deeply with an ERP, warehouse, point of sale or supplier systems |
| Platform fees are a small share of margin | Transaction fees and app subscriptions have become a line item that grows with sales |
| Performance on the platform is acceptable | Speed, search and scale are part of the competitive position |
Many successful businesses use a middle path: a commerce backend from an established provider handling catalogue, inventory, checkout and payments, with a custom storefront on top that gives full control of the experience. It is the most common custom e-commerce project we build.
Which features belong in a custom first release?
- Catalogue. Products, variants, categories, images, stock. Modelled for your products, not for generic ones.
- Search and navigation. Fast, with filters that match how customers actually choose. This is where custom stores win or lose.
- Product pages designed for conversion: images, information, availability, delivery promise, clear call to action.
- Cart and checkout. Guest checkout, saved details for returning customers, address validation, shipping options, taxes, and payment through a provider with wallets and local methods.
- Orders and fulfilment. Order management, status updates, shipping labels, returns.
- Customer accounts. Order history, addresses, saved payment methods.
- Admin and reporting. Product and order management, promotions, basic sales reporting.
- Transactional email. Confirmations, shipping updates, returns.
Later: personalisation, loyalty, subscriptions, marketplaces for third-party sellers, mobile apps, international storefronts, advanced merchandising.
Which integrations matter?
- Payments. Through a provider, with cards, wallets and the local methods your markets use.
- Shipping. Carriers or a shipping aggregator for rates, labels and tracking.
- Accounting and ERP. Orders, invoices and stock flowing without re-keying. For established businesses, this is usually the reason for going custom.
- Warehouse and inventory. Real-time stock across channels, so that the site never sells what the warehouse does not have.
- Marketing tools. Email, analytics, advertising pixels, review platforms.
- Marketplaces and channels. Selling the same catalogue through third-party marketplaces and social commerce.
Why does performance matter so much?
Every fraction of a second of page load costs conversions, and search engines rank fast stores higher. Custom e-commerce lets you control this fully: optimised images, fast search, pages that render quickly on mobile, and infrastructure that stays fast on the busiest day of the year. One of the earliest projects that established 7L's reputation was optimising the sales of large e-commerce websites, and the lesson has not changed: speed is a feature customers pay for without knowing it.
What technical decisions matter most?
- Backend commerce engine. Established commerce backend with a custom storefront, or fully custom. The first is faster and cheaper. The second is right when the catalogue or pricing logic cannot be expressed in a standard engine.
- Catalogue and pricing model. Get variants, bundles, customer-specific pricing and tax right in the data model. Retrofitting them is painful.
- Search. A dedicated search service with filters, synonyms and relevance tuning.
- Mobile first. Most traffic is on phones. Design and test there first.
- Security. Card data with the provider, never on your systems. Secure accounts, protection against bots and fraud.
What does it cost and how long does it take?
| Scope | Typical cost | Timeline |
|---|---|---|
| Custom storefront on an established commerce backend | $50,000 to $150,000 (€44,000 to €130,000, £37,000 to £110,000) | 3 to 5 months |
| Fully custom platform with catalogue, checkout, orders and two or three integrations | $150,000 to $400,000 (€130,000 to €350,000, £110,000 to £295,000) | 5 to 9 months |
| Multi-market, multi-channel platform with ERP and warehouse integration | $400,000 to $1,000,000 (€350,000 to €870,000, £295,000 to £740,000) | 9 to 15 months |
What mistakes do e-commerce founders make?
- Building custom before proving that the products sell.
- Rebuilding standard features an established engine provides, instead of customising the part that is actually different.
- Treating the ERP integration as a detail.
- Designing on desktop and testing on desktop.
- Launching without a plan for the first hundred orders: who packs, who answers, what happens on a return.
How 7L builds e-commerce
E-commerce software is one of our core services, and optimising the sales of large online stores was among the projects that built our reputation. We build custom storefronts on established commerce backends, fully custom platforms where the business needs them, and the integrations with ERP, warehouse and point-of-sale systems that make an online store part of the whole business. If your store has outgrown its platform, or you are planning one that no platform fits, tell us what you sell and how.
Frequently asked questions
Is a custom store better for search engines?
It can be, because you control speed, structure and content fully. Established platforms are also capable of ranking well. The advantage of custom is that nothing about the platform limits what you can do, which matters most for large catalogues and competitive categories.
Can I move from an established platform to custom without losing my ranking?
Yes, with care. Keep URLs the same or redirect every old one, preserve product content and structured data, and launch when the new site is at least as fast. A migration plan is part of the project, not an afterthought.
Do I need a mobile app for my store?
Rarely, at first. A fast mobile web store reaches everyone. Apps make sense for stores with frequent repeat purchases and a loyal base, where notifications and a home screen icon drive sales.
What is a headless storefront?
A storefront built separately from the commerce backend, connected through an API. It lets you design the customer experience freely while the backend handles catalogue, orders and payments. It is the middle path described in this guide.
How do I handle taxes and shipping across countries?
Use specialist services for tax calculation and shipping rates rather than building the rules yourself. They stay current with changing regulations and carrier pricing. Integrate them, do not replicate them.