When an online shop needs custom development, and what it should cost in the UK (2026)

This guide is for the owner or operations lead of a UK business whose online shop needs something built for it alone: a warehouse system to connect, a pricing rule, a page element, an admin tool. It covers which jobs need custom ecommerce development, what UK agencies publish as prices, why a fixed quote beats a day rate, and what a quote must say. Disclosure: we build Orbit Commerce, a hosted ecommerce platform with an in-house development team, so weigh the Orbit parts accordingly. Every figure was checked against its linked page on 8 November 2026.

Do you need custom development at all? Five requests that usually need no code

Most briefs that reach us are not development jobs: a feature the owner has not found, a plugin still to try, or a spreadsheet job dressed up as a project. Check these five before anyone quotes.

1. A setting. “Only approved trade customers may buy”, “charge more for heavy parcels” and “a sale that ends Sunday night” all sound bespoke. On Orbit they are the B2B purchase wall (Enterprise plan), shipping zones with weight bands, and a sale price with a start and an end. Search the help centre, then ask support.
2. A plugin. Accounting sync, forms, calculators, a CRM, live chat and loyalty points are add-ons, priced on their own pages in the plugin store and installable on any plan. The Xero and QuickBooks plugins carry every sale, fee and refund into your books, and Form Builder makes contact and registration forms with file uploads. The Calculator Builder, which has a free plan, turns a measurement into the quantity to buy and, on its paid plan, puts that quantity in the basket. For the bookkeeping method, see ecommerce bookkeeping in Xero or QuickBooks.
3. A CSV import, or the bulk editor. “Update 3,000 prices”, “bring our old redirects across” and “load 200 trade accounts” are spreadsheet jobs. A price or stock list keyed by SKU updates existing products, a redirect map imports from a CSV or Excel file of up to 25 MB, and companies import from CSV on Enterprise. The bulk editor is a spreadsheet view of the whole catalogue.
4. A page builder block. “A banner only trade customers see” and “a free-delivery bar until the basket reaches £150” are display conditions on an ordinary block in the page builder, which reads customer tags, cart total, stock level and the date. Every page also takes custom CSS and a code block.
5. An automation. Already running: an abandoned-cart reminder, a redirect whenever a page’s address changes, scheduled publishing, timed sale prices and smart categories. For the rest, the Workflows plugin reacts to order, customer, fulfilment and payment events with delays, conditions and actions such as tagging an order.

Our own team works the same way: if a setting or plugin would do it, we say so instead of quoting.

The five jobs that do need bespoke code

Here the work is specific to your business, so someone writes it in code.

1. An integration with an ERP, WMS, CRM or accounting system. Orders out to the warehouse, stock and prices back, or trade companies and price lists kept in step with finance. The commonest custom job, with the most ways to go wrong.
2. A new page builder element. A delivery-slot picker tied to your van rounds, a branch stock checker. Built properly it lands in the library like any other block and your team styles it from the settings panel.
3. An admin tool private to one store. A returns triage board, a supplier scorecard. On Orbit it ships as a plugin private to your store, installed through a link bound to it, never listed, with its own dashboard page.
4. A storefront design of your own. An interaction designed for your shop alone, or your own front end over the GraphQL storefront API.
5. Performance work on a very large catalogue. Tens of thousands of variants behave differently from a 400-product shop. It starts with measuring your store on your data; a quote without measurement is a guess.

What does custom ecommerce development cost in the UK in 2026?

Few UK agencies publish a rate card, but several publish ranges in their blogs. These are the ones we read on 8 November 2026: vendors’ figures, published to win work, so the shape of the market rather than a price list.

Why a fixed quote beats a day rate

A day rate moves the risk to you: if the ERP’s API turns out to be half documented, the days go up and so does the bill, and nobody did anything wrong. A fixed price against a written scope puts that risk with the people who know how long the work takes, and forces the useful conversation first: what is in, what is out, what counts as done. If someone cannot quote until they have started, buy the discovery as a fixed piece and have the build quoted at the end; discovery alone can run £8,000 to £15,000 when ERP or B2B logic is in scope (WebDigita, June 2026, checked 8 November 2026). Keep day rates for small, capped support after hand-over.

What a quote for an integration must specify

Most disputes come from a quote that said “connect the shop to Sage” and nothing else. The scope should answer:

• What moves. Orders, payments, fulfilments, stock, prices, products, customers, companies and price lists, each named. “Orders” alone does not say whether refunds move.
• Which direction. Orders usually go out, stock and prices come back; two-way sync needs a rule for which system wins.
• How often. As it happens (a webhook when an order is paid), on a schedule (stock every 15 minutes, prices nightly), or on demand.
• What happens on failure. The warehouse system is offline for an hour on Black Friday: does the integration retry, for how long, who is told, and how does it catch up?
• Who owns the code. Anything built only for your store should be yours, with the source. Get it in writing, with the licence of any middleware in between.

Do it yourself, a plugin, or a custom build?

How Orbit’s custom development works

Our team writes the platform, and the process is the same for every brief. Send something rough: screenshots, a link to something similar, or a paragraph. If it is confidential, send your NDA and we sign before we scope. You get a scope, a timeline and a fixed price in writing, plus anything we would push back on, or a straight answer that a setting or plugin already does it. The price moves only if the scope does. The build is tested against your store and your data and walked through with you before it goes live, and hand-over comes with notes, set-up instructions and the source for anything bespoke. Support is quoted on its own, never folded into the build price. Bespoke code is yours; if part of it would help every Orbit merchant, the quote says so and that part becomes a platform feature we maintain.

The form asks for a budget band from under £5,000 to £50,000 and up. Briefs of every size are read; a job of less than a few days is hard to scope well, so a small request is usually pointed at a setting, a plugin or the docs. It also asks where you start from:

• I run an Orbit store. Send the brief with your store’s name, so it is scoped against your set-up.
• I’m an agency. Bring us in, or build it yourself on a free partner account and send each client store its own install link. The agency programme covers the client-store side.
• I’m moving to Orbit. Book a call: the migration (products, customers, orders, redirects and trade accounts through the importers) and the build are scoped together. Read changing platform without losing your rankings first.

The technical ground it is built on

Everything we build uses the public tools your own developers could use, documented at developers.orbitcommerce.net.

• A REST API for products, inventory, orders, fulfilments, customers and more (companies, catalogues, purchase orders and picking on Enterprise), with a scoped key per integration and separate limits of 600 reads and 300 writes a minute.
• Webhooks on order, payment, fulfilment, product and customer events, each delivery signed with HMAC-SHA256, tried up to four times with a growing wait, and logged.
• A GraphQL storefront API for a headless build.
• Private plugins installed through a link bound to one store, with their own dashboard page.
• An MCP connection so Claude or ChatGPT can work in the store within the scopes you approve, revocable at any time.

A one-page brief you can copy

Fill in these six parts on one page, replacing the brackets, and you should get a real quote first time.

1. The job. “When [an order is paid], [what should happen], so that [the business reason].” For an integration, list what moves and which way.
2. Who does it today. [Name or role], by hand, how often, and how long it takes. A screenshot of the spreadsheet counts.
3. The systems, by name and version. [ERP / WMS / CRM / accounting package], a link to its API documentation, and a sandbox or test account. If it has no API, say so.
4. The deadline that matters. [A date] and why: a peak season, a contract, a system being retired.
5. The budget range. One of the five bands on the form, from under £5,000 to £50,000 and up.
6. The NDA. Attach yours if the work is confidential, to be signed before scoping starts.

Where Orbit fits

Whether you are on Orbit or thinking of moving, the route is the brief form on the custom development page. It brings a reply with the scope and the timeline, a fixed price in writing before any code, and a straight answer when a setting or plugin would do. Every plan from Solo at £25 a month ex VAT has the API with scoped keys, signed webhooks, the page builder, the importers, the bulk editor and the plugin store. B2B, the operations suite and checkout design are on the Enterprise plan at £999 a month ex VAT (£749 a month billed yearly); the B2B page sets out what a trade integration works with. Agencies have the agency programme and a free partner account. For storefront work, start from a theme in the theme store before briefing a design change. Or book a call.

Read next: taking a trade counter online, fifteen shop jobs you can stop doing by hand and running client shops as an agency.

Questions people ask about custom ecommerce development

How much does custom ecommerce development cost in the UK?

A fixed quote against a written scope is the only real answer. For the shape of the market, UK agency and vendor pages read on 8 November 2026 put a packaged Shopify to Sage 50 connector at £600 set-up plus £95 a month or more. They put a connector built for you at £8,000 to £40,000 and more, and a Shopify Plus build at £15,000 to £180,000. All are vendors’ figures. Orbit’s brief form asks for a band from under £5,000 to £50,000 and up.

What is the difference between a plugin and custom development?

A plugin is built once for many shops and priced on its own page, so it is the cheap answer to a common need. Custom development is built for your shop alone, against your systems and data, and you own the result. If more than a handful of shops would want the same thing, look for a plugin first.

Should I pay a day rate or a fixed price for ecommerce development?

A fixed price against a written scope. A day rate moves the risk of surprises to you, and integrations are full of them. If a developer cannot quote until they have looked, buy the discovery as a fixed piece with the build quoted at the end. Keep day rates for small, capped support after hand-over.

Do I need the Enterprise plan for an ERP integration on Orbit?

No. The API, scoped keys and signed webhooks come with every plan, so an integration moving orders, stock, prices, products and customers works on any of them. Enterprise is needed only when it touches B2B companies and price lists or the operations suite’s purchase orders and picking, which live on that plan.

Who owns the code when someone builds something for my shop?

Get it in writing before you sign. On Orbit, bespoke code is yours with the source; if part of it would help every merchant, the quote says so and that part becomes a platform feature Orbit maintains. Ask an agency the same about any middleware between your shop and your other systems, because you keep paying for a connector you cannot take with you.

If your job is in the first list, the 14-day free trial, no card required, is long enough to prove it on your own catalogue. If it is in the second, send the brief and get a price before a line of code is written.