Ecommerce development in London
London's direct-to-consumer brands tend to outgrow their first shop in the same order: the catalogue first, then stock across more than one warehouse, then the checkout. By the time a brand is selling into Europe and the US from London, the platform is holding together a storefront, an ERP, a 3PL and a payments provider with scripts someone wrote before the last peak.
We work on those joins. Checkout flows that handle 3-D Secure challenges without abandoning the basket, stock that is right across channels, order data that reconciles with what the warehouse shipped and what the bank received. Whether the answer is a better Shopify setup or a headless build depends on how much of the business is actually custom, and we will tell you plainly which side of that line you are on.
Financial services drive more of London's software demand than any other sector. Payments companies, challenger banks, wealth platforms and brokers need ledgers that reconcile, APIs that stay correct when a partner retries, and apps customers trust with their money. Most of them reached the market fast, which was the right call at the time, and now run systems built for launch rather than for the size they have become. The work is making those systems dependable without stopping the business that runs on them.
Insurance is its own case. The specialty insurers, managing agents and brokers around Lloyd's still run much of their work on ageing policy administration platforms and spreadsheets that travel between firms by email. Lloyd's has moved away from Blueprint Two, the market-wide programme that was meant to digitise placement and claims, so each firm is modernising its own systems one integration at a time. The City's law firms and consultancies sit alongside them, holding decades of documents and few ways to search them by meaning.
Media, retail and the public sector bring different problems. Publishers run subscriptions, paywalls and content systems that have to hold up on a busy news day. Direct-to-consumer brands outgrow their first shop as they start selling into Europe and the US. Suppliers to councils and NHS bodies build services that have to work for every resident, including people using a keyboard or a screen reader. Hiring is the common constraint. ITJobsWatch puts the median advertised salary for a software engineer in London at £98,750 over the six months to September 2026, and banks, fintechs and the large technology firms compete for the same people.
Working with us from London is straightforward. Four hours of every working day overlap with yours, set across your morning, so stand-up, code review and the decisions that follow happen live. You talk to the engineer who writes the code, in your own Slack, GitHub and Linear. The rest of the day moves forward in pull requests you can read at your desk, with runbooks and architecture notes written as the work goes.
We are the right fit when you have a defined piece of work and need senior engineers on it this month rather than next quarter. Start with a fixed-price two-week piece and judge us on what ships. We add capacity while a London hire is still in progress, and we work white-label under your name for agencies.
Four ways this arrives.
The ERP updates overnight, the store sells all day, and by morning the two do not match. We build the sync as a queue with retries and reconciliation, decide which system wins for each field, and alert on drift before a customer buys stock you do not have.
Or checkout slows until people give up. We cache what can be cached at the edge, keep live stock checks off the browsing path, load-test the shape of a real launch rather than a steady trickle, and queue anything that cannot scale.
Bundles, B2B price lists, subscriptions, delivery rules by postcode. We build it as a custom Shopify app or with Shopify Functions and checkout extensions so it survives platform updates, or tell you when you have outgrown the theme altogether.
Payment webhooks can arrive twice, late or out of order, and the handler trusts every one. We make order state follow the provider's record, process Stripe and Razorpay events idempotently, and reconcile daily so a mismatch is a report, not a complaint.
An hourly sync with a third-party system reachable only through its API, with values normalised at the boundary so unchanged records stop looking changed.
Read the write-up →Asked by London teams.
How do you work with teams in London?+
Four hours of every working day overlap with yours, set across your London morning, so stand-up and code review happen live. We join your calls and work in your tools: Slack, GitHub and Linear. You talk directly to the engineer who writes the code. Outside the overlap, the work carries on in pull requests you can read at your desk, and runbooks and architecture notes are written as we go.
Do you build for London fintechs and insurers?+
Yes. For payments companies, challenger banks and wealth platforms we build ledgers that reconcile, webhook handling that stays correct when a provider retries, and React Native apps with biometric sign-in and step-up checks for risky payments. For insurers, managing agents and brokers around Lloyd's we replace spreadsheet workflows with internal tools: bordereaux intake, referral queues and approvals, connected to the policy systems you already run.
How does your rate compare to hiring in London?+
ITJobsWatch puts the median advertised salary for a software engineer in London at roughly £99,000. Our published rate is $35/hour, with a $5,000 minimum engagement. There is no recruiting time and no employment overhead, and we can start within days of the first call. Most clients begin with a fixed-price two-week piece at $2,800, so you judge us on working code before committing to more.
Can you work white-label for a London agency?+
Yes. London agencies bring us in when a client project needs more senior backend, mobile or infrastructure work than the team has free. We work under your name, in your repositories and your client's tools, and you stay the face of the project. The NDA comes before specifics, the code belongs to the client from the first commit, and runbooks and architecture notes are written as we go.
Have you built a store like ours?+
We build stores from the parts of commerce that usually go wrong, and those are what we work on every day: syncing with a third-party system that only speaks through its API, handling webhooks that arrive twice, and background jobs that must not lose or repeat work. On a call we will walk you through how that applies to your store.
Shopify, headless, or fully custom?+
Start with Shopify if a theme and a few apps cover you; that is cheaper than anything we would build. Go headless when the storefront must do things a theme cannot, or share a front end with other products. Build on Medusa or commercetools when the catalogue, pricing or order flow is genuinely unusual. Most stores never need the third option, and we will say so.
Can you connect our ERP or warehouse system?+
Usually, if it has an API or can export files on a schedule. We start by agreeing which system owns each field, such as stock, price and order status, because most sync bugs come from two systems both believing they are the source of truth. Then we build the sync with retries, a log of every change, and a daily reconciliation report.
Which payment providers do you work with?+
Stripe, Razorpay, and Shopify Payments when the store runs on Shopify. Choose the one that suits your markets and fees; we earn nothing from any of them. The work that matters is the same for all three: treat the provider as the record of what was paid, handle every webhook idempotently, and test refunds and partial captures, not only the happy path.
How do you prepare for a sale or a launch?+
We load-test the whole journey, from landing page to paid order, at the traffic you expect and beyond it. We find what breaks first, which is usually a third-party script, an uncached page or the stock check, and fix it before the day. During the sale itself, the engineer who did that work is watching the dashboards with you.