Custom Software Development London: 2026 Pricing Guide

A London SME asking for a fixed quote on "a custom platform" will get answers ranging from £15,000 to £150,000 for what sounds like the same project description. The gap isn't agencies padding numbers — it's that "custom software" is not one product with one price. It's a category, and the variables inside it move the final invoice more than any single feature does.

This guide sets out the actual 2026 pricing bands Code Melodies Ltd works within for London-based clients, what pushes a project to the top or bottom of each range, and how to read a quote so you're comparing like with like rather than comparing a headline number.

In this article

• Why Two "Similar" Projects Can Cost Wildly Different Amounts
• 2026 Pricing Bands for London Software Projects
• The Integration Count Problem
• What a London Premium Actually Buys
• AI Integration: Where the Range Gets Wide
• Reading a Quote: What to Ask Before You Sign
• Where This Fits Alongside Other Costs

Key takeaways

• Custom software builds in London range from £15,000 to £120,000+, with integration count being the single biggest driver of cost, not the visible feature list.
• AI/ML development pricing (£6,000–£60,000) varies widely because data pipeline quality, not model choice, is the main source of cost overrun.
• A proper quote should separate discovery cost from build cost and state the assumed number of third-party integrations before any final number is given.
• Code Melodies Ltd runs a free 90-minute discovery session to scope real requirements before quoting, rather than pricing from a written brief alone.
• London day rates sit above the UK average, but a well-scoped project can still land at the lower end of a price band if requirements are clean.

Why Two "Similar" Projects Can Cost Wildly Different Amounts

Two ops directors describe near-identical requirements — a portal for managing supplier orders, some reporting, a login system — and get quotes £40,000 apart. The difference is almost never the visible feature list. It's the number of external systems the new software has to integrate with, the state of the client's existing data, and whether compliance requirements (data residency, audit logging, role-based access controls) are baked in from day one or bolted on later.

We quoted a logistics client last year at £52,000 for what looked, on paper, like a straightforward dispatch portal. Discovery revealed their existing order system had no documented API and three different spreadsheet-based workarounds staff used to patch gaps. The build itself took six weeks. Untangling and mapping the existing data took another four. That's the part a headline quote rarely shows.

2026 Pricing Bands for London Software Projects

These are the ranges Code Melodies Ltd quotes within for London and wider UK/European clients, based on current project scopes. Final cost depends on project scope, data volume, number of integrations, and ongoing support requirements.

ServicePrice RangeTypical TimelineWhat Moves the Price AI/ML Development£6,000–£60,0003–18 weeksTraining data quality, number of models, whether it's a single pipeline or multi-provider orchestration Cybersecurity Audit£1,800–£18,0001–4 weeksNumber of systems in scope, whether penetration testing is included, compliance framework required Cloud Migration£3,500–£35,0002–10 weeksVolume of data, legacy system complexity, whether downtime is tolerable during cutover Managed IT Support£55–£160 per user/monthOngoingResponse time SLA, on-site vs remote support, number of endpoints managed Bespoke Software Build£15,000–£120,000+6–26 weeksNumber of user roles, integrations, whether multi-tenant architecture is required

The bottom of each range assumes clean requirements and minimal legacy integration. The top assumes the opposite — multiple data sources, undocumented existing systems, or compliance requirements layered on top of core functionality.

The Integration Count Problem

Ask any development quote how many external systems the software needs to talk to. This single number predicts cost better than almost anything else on a requirements document.

A CRM sync, a payment gateway, and an accounting package integration is a manageable scope — most agencies can price that with reasonable confidence upfront. Add a legacy warehouse management system with no API documentation, and the estimate has to include discovery time just to find out what's possible. We've seen integration discovery alone take longer than building the actual feature it was meant to support.

This is also where fixed-price quotes without a discovery phase become risky for the buyer. A quote given without seeing the client's existing systems is, at best, an educated guess. Code Melodies Ltd runs a free 90-minute discovery session specifically to price this variable properly before any number goes on paper — it's the difference between a quote and a guess.

What a London Premium Actually Buys

London day rates for senior developers sit above the UK regional average, largely due to competition from finance and adtech employers pulling from the same talent pool. That premium is real, but it doesn't automatically mean London-based development costs more overall — a well-scoped project with a London team can still land at the lower end of a price band if the requirements are clean.

What the premium buys, in practice, is depth of experience with compliance-heavy sectors — financial services, logistics, healthcare adjacent work — where a development team has already solved the specific regulatory or architectural problem a client is facing for the first time. That's worth paying for on complex projects. It's not worth paying for on a simple internal tool with no regulatory exposure.

AI Integration: Where the Range Gets Wide

The £6,000–£60,000 AI/ML band is the widest range on our pricing table for a reason. A sentiment analysis pipeline running over clean CRM data can ship in three weeks at the low end. A multi-provider orchestration system — one that routes between OpenAI, Anthropic, and a self-hosted model depending on cost, latency, or compliance needs — took us 18 weeks on a recent build with financial services compliance requirements layered in.

The most common cause of AI project cost overrun we see isn't the model choice. It's the data pipeline. Clients often assume their existing data is analysis-ready; in practice, cleaning and structuring that data can take longer than building the AI logic itself. Bad training data doesn't fail loudly — it produces confident wrong answers, which are more expensive to catch later than an obvious crash.

For a fuller breakdown of scoping an AI project before requesting quotes, our April Triple piece covers the operational side of this in more depth.

Reading a Quote: What to Ask Before You Sign

A proper quote should separate discovery/scoping cost from build cost, state the assumed number of integrations, and specify what happens if scope changes mid-project. Vague line items like "platform development — £45,000" with no breakdown are a signal to ask more questions, not sign faster.

Ask specifically: how many third-party systems does this assume integration with? What happens to the price if that number turns out to be wrong? What's included in post-launch support, and for how long? A credible answer to all three should be available without a follow-up meeting.

Cloud migration and managed IT support quotes carry a similar risk — a per-user monthly figure looks simple until you check whether it includes out-of-hours incident response or just business-hours helpdesk cover. The gap between those two service levels can be £40 or more per user per month.

Where This Fits Alongside Other Costs

Software spend rarely sits in isolation from a business's wider IT and compliance posture. A cybersecurity audit at the lower end of the £1,800–£18,000 range typically covers a single system review; the upper end includes penetration testing across multiple environments and a full remediation plan. Businesses building new customer-facing software for the first time often need both a build quote and a security review quote at the same time — worth asking for both together rather than sequentially, since findings from one affect scope in the other.

You can see the range of platforms this pricing has applied to in our featured projects & case studies, including a partner bidding exchange we built for a logistics client — detailed in our case study on turning hard-to-quote jobs into competitive offers.

Full detail on our service scope sits on our bespoke software development services for UK & European businesses page, and background on how we work is on our about page.

The most reliable way to get an accurate number is still a proper discovery conversation rather than a written brief alone. Let's talk about your project — Code Melodies Ltd runs a free 90-minute discovery session to scope real requirements before quoting, which is the only way to price the integration and data variables that actually determine cost. Call +44 7877 196177 or email info@codemelodies.co.uk to book one.