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A custom e-commerce back office usually costs $11,200 to $18,000 (€10,000–€16,000)excl. VAT to manage orders and fulfillment on top of an existing store, and $18,000 to $28,000 (€16,000–€25,000)excl. VAT with documents, a dashboard and several user profiles. A multichannel tool connected to your ERP and marketplaces runs $28,000 to $56,000 (€25,000–€50,000)excl. VAT.
Your online store works, but the team spends its days in exports, spreadsheets and plugins that contradict each other. A custom back office takes over what Shopify or WooCommerce do poorly: fulfillment, stock rules, B2B orders, returns, reporting. Here is what it costs, how the budget is built, and when you are better off without one.
Price ranges
Amounts exclude VAT and cover a first version in production. The quote becomes fixed after the scoping phase.
| Type of back office | What it includes | Indicative budget | Timeline |
|---|---|---|---|
| Focused back office | Store orders, statuses, fulfillment, accounts and roles | $11,200 to $18,000 (€10,000–€16,000)excl. VAT | 1 to 2 months |
| Complete back office | The focused version + PDF picking slips and labels, dashboard, alerts, data migration | $18,000 to $28,000 (€16,000–€25,000)excl. VAT | 2 to 3 months |
| Multichannel tool | The complete version + several stores and marketplaces, ERP connection, supplier area, AI | $28,000 to $56,000 (€25,000–€50,000)excl. VAT | 3 to 6 months |
Beyond that, when the back office becomes a platform with several areas (brands, resellers, warehouses), it is quoted individually. For a range that fits your case, the estimator gives you a budget in one minute.
How the budget is built
My estimator starts from a base price, adds the modules you need, then applies multipliers. An illustrative example for a back office connected to a Shopify store, used by a team of 15 (customer service, fulfillment, management):
| Item | Amount excl. VAT |
|---|---|
| Business app base | €6,000 |
| Accounts and roles | €1,500 |
| Back office | €2,000 |
| Store connection | €2,000 |
| PDF picking slips and labels | €1,500 |
| Dashboard | €1,500 |
| Notifications | €1,000 |
| Data migration | €800 |
| Subtotal | €16,300 |
| 10 to 50 users (×1.1) | €17,930 |
Add an ERP connection and a marketplace connection (€2,000 each) plus a supplier area (€2,500), and you go past $28,000 (€25,000)excl. VAT. This is an order of magnitude: the fixed quote follows scoping.
What drives the price
- The number of channels. One store is one connection. Three stores and two marketplaces are five connections, each with its own formats, limits and changes. See centralizing orders and stock across several marketplaces.
- API quality. Shopify, for example, states that its REST Admin API has been “legacy” since October 1, 2024, and that new public apps must be built exclusively with the GraphQL Admin API since April 1, 2025 (Shopify documentation, checked in October 2026). A new connector has to start on the right API, or it will need rebuilding.
- Stock rules. Single multichannel stock, reservations, batches, expiry dates, several warehouses: each rule takes design and testing.
- B2B. Customer-specific prices, orders on account, invoices with payment terms: a back office that also serves resellers gets close to a B2B portal.
- Data migration. Order history, customers, products and variants to bring over from the old system.
What the price includes, and what it does not
The quote includes scoping with your teams, clickable mockups, development in batches tested by your teams, go-live, the planned data migration, training and three months of support. The source code and rights are transferred to you once paid in full.
Not included:
- hosting for the back office, from a few tens to a few hundred euros a year;
- subscriptions for the store, any plugins you keep and the marketplaces;
- usage-based third-party services: carriers, labels, email, AI;
- maintenance, which includes updating connections when a platform changes its API.
A custom back office often lets you cancel several paid plugins. Run the numbers over 3 years with the total cost of SaaS versus custom method.
When a custom back office is not the right choice
- Low order volume, handled by one or two people: the Shopify or WooCommerce admin, with one or two well-chosen plugins, is enough.
- A need covered by a solid, maintained plugin: try it before building anything.
- A store that is itself unstable or nearing end of life: fix the platform first. The question is covered in Shopify Plus or a custom back office.
Custom work makes sense when your teams lose hours every day to re-entry, when stock errors cost sales, or when the way you sell (B2B, multichannel, subscriptions, personalization) goes beyond what the platform can do.
How the project works
- A 30-minute call to understand your channels, your flows and the tasks that take the most time.
- Scoping (1 to 2 weeks): priorities, connections, stock rules, fixed quote.
- Clickable mockups (1 to 3 weeks), tested by the team that will use the tool.
- Development in batches: the most costly flow first, then the next ones. The store keeps running throughout the project.
- Gradual go-live, with data migration and training.
Payment follows the same rhythm: a 50% deposit at the start, the balance according to the schedule in the quote.
Frequently asked questions
Do we have to leave Shopify or WooCommerce to get a custom back office?
No, in most cases. The store stays in place for the storefront and checkout; the custom back office connects to it through the API to handle what it does poorly: fulfillment, stock rules, B2B, returns, reporting. It is often the lowest-risk option.
How long does it take to build an e-commerce back office?
Allow 1 to 3 months for a focused back office, and 3 to 6 months for a multichannel tool connected to your ERP. Development happens in batches, starting with the flow that costs your team the most time.
Can the back office handle several stores and marketplaces?
Yes, that is one of its main benefits. Orders from every source land on the same screen, with a single stock count. Each additional channel is a connection to price, and its cost depends on the quality of that channel’s API.
What happens if Shopify or a marketplace changes its API?
The connection has to be updated. Vendors usually announce these changes in advance and version their APIs. Keeping up with them is part of maintenance, to include in the annual budget.