Bespoke Software Development in London: Rates and Reality

A search for bespoke software development London returns several hundred firms charging between £400 and £1,800 a day for what looks, from the outside, like the same work. Almost none publish a price. The spread is real and it is explicable, but nothing on those websites explains it, and a buyer holding three proposals cannot tell whether the expensive one is better or simply more expensive.

What follows is how that pricing is built: the salary and property costs underneath a London day rate, the four commercial models an agency will offer, what a blended rate conceals, and what a project of a given shape costs once discovery, testing, migration and the first year of support are counted. It also covers the contract terms that decide more of the outcome than the rate does.

Rates here are house estimates from what we see quoted and won in London. Where a figure comes from an official source it is cited and dated.

What does bespoke software development in London cost? Expect £550 to £1,100 a day from a small studio or a mid-sized agency, and £1,100 to £1,800 from a consultancy. A small internal tool lands around £45,000 to £70,000, a customer facing system with integrations between £200,000 and £350,000, and a complex integrated platform between £1 million and £3 million. Those bands are house estimates, not a published rate card.

What “Bespoke” Actually Commits You To

Bespoke means commissioning something that does not exist and taking on the cost of its whole life, not only its construction. The build is the visible part. What follows is hosting, dependency updates, security patching, platform change, staff turnover on both sides, and the slow accumulation of features nobody designed for.

A configured product transfers most of that to a vendor, along with their data model and their release schedule. Bespoke reverses the trade. The reason to take it is that the process you run differently is the process that makes you money, and no product models it properly. The reason not to is anything else.

Treat the commitment as a multi-year one from day one. Annual running and change costs settle at 15 to 25 per cent of the original build cost once a system is in real use. That is a house observation, and it is the number that decides whether a build was affordable. Our custom software buyer’s guide works through the build against buy decision in more depth.

Most Projects Labelled Bespoke Should Not Be

Read a typical brief and four fifths of it is commodity: accounts and authentication, a content model, permissions, invoicing, an admin area, reporting, notifications. The differentiator is usually a tenth of the scope. Building the commodity portion from scratch is how a project that should have cost £120,000 arrives at £400,000 with nothing distinctive in it.

The honest answer for most buyers is a bought core with a bespoke edge. Buy the accounting package, the CRM and the identity provider, and spend the bespoke budget on the processes a competitor cannot copy by buying the same licence. The test is blunt. If a competitor bought the same product tomorrow and configured it identically, would you be materially worse off? If not, buy it.

An agency paid by the day has a structural incentive not to say this, so hearing it unprompted is a good sign. It is the first conversation we have on any software development engagement, and it usually removes more scope than it adds.

The London Premium, Measured Rather Than Assumed

Start with something official rather than a recruiter’s brochure. The ONS publishes median monthly pay from PAYE Real Time Information, and in the August 2026 release median monthly pay across the UK was £2,642 for July 2026, against £3,116 for London. That is a premium of roughly 18 per cent on the median employee, drawn from tax records rather than a survey.

The spread inside London is wider than the gap between London and the country. Borough medians on the same measure ran from £2,624 in Enfield to £4,016 in Wandsworth, which is one reason an agency in Zone 4 and one off Old Street can both quote honestly and differ by a third.

For the annual picture the reference is the Annual Survey of Hours and Earnings. The ONS bulletin Employee earnings in the UK: 2025 put median gross annual earnings for full-time employees at £39,039 in April 2025, up 4.3 per cent on £37,439. Software pay sits well above that.

What Actually Drives the London Premium

An 18 per cent gap in median pay does not produce an 18 per cent gap in day rates. It compounds through three multipliers, and the third is the one buyers never see.

Salary, and the floor the state publishes

There is no neutral published average for a London software salary, and the guides claiming to have one are marketing for recruitment firms. The nearest official anchor is the Home Office going rate: GOV.UK lists £54,700 a year, or £28.05 an hour, as the going rate for occupation code 2134, programmers and software development professionals, on the Skilled Worker route.

That is a visa threshold rather than a market rate, and it is national rather than London specific. Its value is being published, dated and written by nobody selling you a candidate. A senior London engineer sits well above it.

Everything that sits on top of salary

Salary is not the employer’s cost. For the 2026 to 2027 tax year, HMRC’s rates and thresholds for employers set employer secondary Class 1 National Insurance at 15 per cent on earnings above a secondary threshold of £5,000 a year. Pension contributions, holiday, sick pay, equipment, insurance, training and recruitment fees sit on top.

Together those take the fully loaded cost of an engineer to roughly 1.2 to 1.3 times salary, before a square foot of office or an hour of management is counted. That multiple is a house figure and it varies most with pension generosity and recruitment churn.

Property, rates and the cost of a desk

Commercial property is the London specific cost, and business rates make it visible. The government’s notification of non-domestic rating multipliers for 2026/27, published on 10 February 2026, sets the standard multiplier at 48.0p, the small business multiplier at 43.2p for rateable values up to £50,999, and a high value multiplier of 50.8p for rateable values of £500,000 and above.

Central London office floors land in that top band, and rates are charged before any rent. An agency that gave up its office bills a lower rate honestly. One that kept a Shoreditch floor is passing on a cost you can choose not to buy.

How a Day Rate Is Actually Built

The arithmetic is worth doing once, because it turns a rate that feels arbitrary into a number you can argue with.

Take an engineer on £90,000. Employer National Insurance at 15 per cent above the £5,000 threshold adds about £12,750. A five per cent pension adds £4,500. Equipment, software, insurance and training add perhaps £5,000. The loaded cost is around £112,000 before anyone has managed, sold or housed them.

Now count billable days. A year holds roughly 253 working days, and removing 25 days of holiday and 8 bank holidays leaves 220. Take out interviewing, internal work, training, sickness and the gap between projects and about 200 are genuinely billable. Divide £112,000 by 200 and the raw cost of that engineer is about £560 a day.

Everything else in a quoted rate is premises, management, sales, finance, recruitment, unbilled discovery and margin. A quoted £900 to £1,000 is a 1.6 to 1.8 multiple on raw cost, which is normal rather than greedy. Below about £600 in London, somebody is either running at very high utilisation or not employing the person doing the work.

How Agencies Price, and What Each Model Does to the Incentives

Four models cover almost everything you will be offered, and each moves risk somewhere different.

Time and materials at a day rate means you buy hours. The supplier is paid for effort rather than result, so it works when you can direct the work weekly and read the output, and fails quietly when you cannot tell good progress from busy progress.

A blended team rate means you buy a team for a period, usually a month or a sprint. Revenue becomes predictable for the supplier and spend becomes predictable for you. The risk moves to the composition of the team.

Fixed price means you buy a defined scope. The supplier prices uncertainty in and then defends the boundary, because every hour beyond the estimate comes out of margin. Change requests become the profit centre.

Outcome based pricing ties fees to a result, and works only where that result is measurable, attributable and largely within the supplier’s control. That describes conversion rate work far better than a back office rebuild, and most real examples are a discounted rate with a bonus attached.

The Blended Rate, Explained Properly

A blended rate is a single day rate applied to a whole team, calculated as the weighted average of individual rates by allocation. It is the number most London proposals are built on and the one buyers question least, because a single figure feels like a discount even when it is not.

The important property is that a blended rate says nothing about who does the work. Two teams with the same blended rate can differ by a factor of two in output, because one has a technical lead half time and the other a graduate full time. Averages hide composition.

A worked blend

That team costs £3,770 a day across 4.8 full time equivalents, so the blended rate is about £785 even though the headline senior rate is £850 and the lead is £1,000. Ask for the allocation table, not the blended number.

How the blend drifts

The failure mode is silent substitution. If the technical lead drops from 0.5 to 0.2 and a graduate at £450 takes the slack, the blended rate falls, the invoice looks better and delivery slows. If the mix shifts junior while the blended rate holds, the supplier’s margin rises and you pay the same for less. Put the named team and the allocation in the statement of work, require notice of any substitution, and review actual against planned monthly.

What Bespoke Software Development London Actually Costs

These are house bands, built from proposals we win and lose against. Treat them as the range a competent supplier of that shape quotes in 2026, not as a published tariff.

Day rate bands by supplier type

In prose: a London freelance contractor usually sits between £400 and £700 a day, rising to £700 to £950 for a genuine specialism such as payments, real time systems or a regulated domain. A studio of two to ten people quotes £550 to £850, an agency of ten to sixty quotes £750 to £1,100, and a consultancy quotes £1,100 to £1,800.

What moves a supplier between bands

Four things move a supplier up a band, and none of them is quality of code. Regulatory exposure comes first, because financial services, health and public sector work carries audit, clearance and insurance costs a marketing site does not. Indemnity and liability caps come second, since a supplier willing to carry real liability prices for it.

Third is bench depth, which is what you actually buy from a larger firm, because a studio of four cannot absorb a resignation mid-project. Fourth is the sales cost of winning you, which is highest where procurement is heaviest, and is why the same engineer costs more inside a consultancy.

Worked Example: A Small Internal Tool

Take an operations tool replacing a spreadsheet: forms, a workflow with three states, role based access, exports, and one integration with an existing accounting system. No public users, perhaps forty internal ones.

A London studio staffs this with one senior full stack engineer for eight weeks, a designer for two of those weeks and a delivery manager for a day a week. At £850, £750 and £800 that is roughly £34,000 of engineering, £7,500 of design and £6,400 of delivery, so £48,000 before anything around the build. Add a five day discovery at around £4,500 and the quote lands near £53,000.

The realistic band is £45,000 to £70,000, and the upper end is almost always integration. A documented accounting API keeps you at the bottom. A twenty year old system with a nightly file drop moves you to the top on its own.

One experienced contractor at £550 a day for forty five days does the same job for about £25,000, with no designer, no delivery manager and no cover if they are ill. Buying capacity as an embedded engineer rather than a project is what hire a web developer describes, and for a tool this size it is often the right trade.

Worked Example: A Customer Facing System

Now a customer portal: accounts, a payment flow, document upload, notifications, an admin back office, and integrations with two internal systems. Public facing, so accessibility, performance and security stop being optional.

A sensible team is a technical lead at 0.4, one senior engineer, one mid level engineer, a designer at 0.2, a delivery manager at 0.3 and a QA engineer at 0.3. At the rates above that team costs about £2,470 a day, so five months of roughly 105 working days puts the build alone near £259,000.

The realistic band is £200,000 to £350,000, and what decides the position within it is rarely the interface. It is the number of integrations, whether their owners will give you a test environment, and whether historic data has to move. Our budgeting guide breaks the same shape of project down by phase.

Two things reliably push this above the band. A payment or identity provider chosen late rewrites flows already built. A stakeholder group with no single decision maker converts every design review into a fortnight.

Worked Example: A Complex Integrated Platform

The third shape is a platform: several user types, five or more integrations, a migration from a system still in daily use, an audit trail somebody external will inspect, and a release schedule that has to survive contact with an existing operations team.

That is eight to twelve people for nine to eighteen months. At a blended £950 and nine full time equivalents the run rate is about £8,550 a day, so a twelve month programme is roughly £2.1 million. The realistic band is £1 million to £3 million, and the width is not vagueness. It is the difference between a migration with clean source data and one without.

Programmes this size fail on organisation rather than engineering. The predictors are a data migration treated as a late task, an integration owned by a third party with no contractual obligation to you, and a parallel run nobody budgeted staff to operate. Any of the three adds months.

If a supplier quotes this shape of work within a fortnight of first contact and without seeing the source data, the number is a bid rather than an estimate.

The Line Items Buyers Forget

Overruns rarely come from the build being harder than expected. They come from work that was always necessary and never in the quote.

Before and during the build

Discovery is the first. A proper one costs 5 to 10 per cent of the eventual build and is the cheapest insurance available. Design is typically another 10 to 15 per cent. Testing is not a phase to be added later, and a team that quotes no QA allocation is telling you the developers will test their own work.

Data migration is the most underestimated line in the list. Extraction, cleaning, mapping, reconciliation and at least two rehearsals commonly reach 10 to 20 per cent of build cost on any system replacing something in active use.

Around and after the build

Infrastructure, third party licences and identity providers are recurring costs the build quote usually excludes. A security review or penetration test before launch is a separate engagement. Accessibility is a legal and commercial risk on any public facing service, and conformance is measured against WCAG 2.2, a W3C Recommendation dated 12 December 2024 that added nine success criteria to the 2.1 set.

Then documentation, deployment automation, handover, training and the first year of support. Ask for every one of these to be priced or explicitly excluded in writing. An excluded line you can plan for. A silent one arrives as a change request.

Fixed Price Versus Time and Materials

A fixed price on a well specified project is a real transfer of risk and worth a premium. A fixed price on a poorly specified project is a fiction that both parties settle later through change requests, and the settlement is always worse for the buyer, because the supplier holds a monopoly on the half built system.

The condition that makes fixed price honest is a specification detailed enough that a third party could price it the same way. If you cannot describe every screen, rule and integration to that level, fix the discovery phase instead, then fix the build once discovery has produced something priceable.

The middle ground that works is capped time and materials: an agreed rate, an agreed team, a not to exceed figure, and a change process requiring written approval above a threshold. Our comparison of fixed price and time and materials covers the contract mechanics.

Whichever you choose, price the change process before you need it. A supplier whose change rate is higher than its build rate has told you where it expects to make money.

Who Owns the Code, and Why It Is Not Automatic

This is the most expensive thing buyers assume rather than check. Paying for software does not give you copyright in it under UK law.

Section 11 of the Copyright, Designs and Patents Act 1988 makes the author the first owner, with an exception for work made by an employee in the course of employment, where the employer is first owner subject to any agreement to the contrary. There is no equivalent exception for commissioned work. GOV.UK guidance on ownership of copyright works states that the first legal owner of a commissioned work is the person or organisation that created it, not the commissioner, unless you agree otherwise in writing.

The mechanism for fixing that is also statutory. Section 90 provides that an assignment of copyright is not effective unless it is in writing signed by or on behalf of the assignor. A verbal understanding, an email and a paid invoice are all insufficient on their own.

So insist on a written assignment clause naming the deliverables, and check when it takes effect. Assignment on final payment is normal. Assignment of everything except a broad reusable components licence needs reading closely, because that carve out is where a supplier keeps the parts you thought you had bought. This is not legal advice and a solicitor should draft the clause.

The Contract Terms That Matter More Than the Rate

Five clauses decide more of the outcome than a hundred pounds a day ever will.

Acceptance criteria come first. Define what “done” means per deliverable before work starts, in testable terms, and tie payment milestones to those tests rather than to dates. A milestone paid on elapsed time rewards elapsed time.

A warranty period is second: a window after go live, typically 30 to 90 days, in which defects against the agreed specification are fixed at no charge. Distinguish defects from changes in writing, or the distinction will be argued about when you are least able to argue.

Source code escrow is third, and it matters where the supplier hosts or holds anything you cannot rebuild. Our guide to software escrow sets out who genuinely needs it. Fourth is an exit clause: notice period, handover deliverables, credential transfer, and a defined rate for transition support.

Fifth is payment terms, which cut both ways. GOV.UK guidance on late commercial payments notes that a business to business payment period longer than 60 days must be fair to both businesses. A small studio pushed onto 90 day terms will price that in or fail mid project.

IR35, VAT and the Rest of the Invoice

Two commercial mechanics change what a quoted number costs you, and neither is advice you should take from an article.

Employment status when you engage contractors directly

If you engage an individual through their own limited company rather than buying a service from an agency, the off-payroll working rules may apply. HMRC guidance on off-payroll working for clients explains that medium and large private sector clients must determine the worker’s employment status, issue a Status Determination Statement with reasons to both the worker and the party they contract with, and take reasonable care doing it. Failing to give reasons can move liability for tax and National Insurance to the client.

Small clients are treated differently: responsibility stays with the worker’s intermediary, though the client must confirm its size when asked. The general IR35 guidance is the starting point and an accountant should confirm which side of the size tests you sit. This is a real reason many buyers prefer an agency contract to a direct one.

VAT on the whole engagement

Agency quotes in London are almost always exclusive of VAT, charged at the standard rate of 20 per cent under GOV.UK’s published VAT rates. If you are VAT registered it is usually recoverable and the headline number is what you pay. If you are not registered, or you are partly exempt, that 20 per cent is a real cost and a £300,000 build is a £360,000 outlay.

A supplier below the registration threshold, which GOV.UK gives as taxable turnover of more than £90,000, may not charge VAT at all. On a project of any size that is a signal about supplier scale rather than a saving to plan around.

Offshore, Nearshore and the UK Outside London

The comparison most buyers make is London against offshore. The comparison they should make first is London against the rest of the UK, because it keeps the jurisdiction, the contract law, the time zone and the working culture while removing most of the premium.

In prose: a capable UK team outside London typically quotes £400 to £750 a day, nearshore Europe £250 to £450 with six to eight hours of overlap, and South or South East Asia £120 to £300 with two to four. Those are house estimates.

The saving is on rate, not on effort, and distributed delivery adds effort. Specifications must be written more precisely because a corridor conversation cannot repair them, and review latency stretches a one hour clarification into a day. A hybrid, with a UK lead and architect against an offshore build team, recovers most of that at a blended rate between the two. Our comparison of UK and offshore delivery covers the management overhead in full.

Comparing Three Quotes That Are Not Comparable

Three London proposals will arrive in three shapes: one fixed price, one blended rate over a period, one phased with discovery priced separately. Comparing the totals tells you nothing.

Rewrite each into the same five fields: total cost excluding VAT, implied day rate, total days by role, what is explicitly included, and what is explicitly excluded. Where a proposal does not give you a number, ask for it in writing rather than estimating it, because the refusal is itself information.

Then check the four exclusions that produce most of the variance: discovery, data migration, testing effort and post launch support. A quote 30 per cent cheaper and silent on all four is not cheaper. It is a different quote for a smaller piece of work.

Finally, compare the team rather than the firm, asking which named people are allocated, at what percentage and for how long. Our guide to writing a software RFP covers the structure that gets comparable answers back.

The Questions That Separate a Capable Supplier From a Plausible One

Ask these in a first meeting and listen for the answer you do not want.

“Who will actually write this, and can I meet them this week?” A capable firm names people. The answer to worry about is that resources are allocated from a pool nearer the start date, which means the proposal team is illustrative.

“Show me the closest thing you have built to this, and put me in touch with that client.” Reluctance here is occasionally confidentiality and usually absence.

“What happens if the effort turns out 20 per cent higher than your estimate?” The answer you want describes a mechanism: a change process, a contingency, a re-planning point. A confident assurance that it will not happen is the answer to worry about.

“How do you test, and what proportion of the estimate is testing?” A number is a good sign. “Our developers test as they go” means the budget has no QA in it.

“When does the IP transfer, and what do you retain a licence to reuse?” Hesitation here is expensive later. Our guide to choosing a development agency expands the list, and technical due diligence covers what to inspect when you inherit a codebase rather than commission one.

Warning Signs and What Makes a Good Client

Half the outcome is the supplier and half is you, and the second half is the half nobody audits.

Signals to slow down on

A fixed price quoted from a one page brief without a discovery call. A proposal arriving within a day of first contact. A proposal that is mostly company boilerplate with three pages of your project at the end. No named team. A refusal to discuss IP assignment or escrow on a system your operations depend on. A senior day rate under £350 in London, which usually means undisclosed subcontracting.

What a good client does

Names one decision maker with authority and makes them available weekly rather than monthly. Returns feedback in days. Accepts that a change costs money and asks what it costs before asking for it. Provides test data, credentials and third party access in the first fortnight rather than the last. Does not run a parallel internal build. Suppliers price all of this in quietly from the first meeting.

Where This Leaves You

London is worth paying for when the work needs people in a room with your staff, when the domain is regulated, or when the cost of getting it wrong is much larger than the cost of building it. It is not worth paying for when the specification is clear, the domain is ordinary and the work can be reviewed remotely. Most buyers are in the second case and pay for the first.

Mecanik builds and maintains bespoke systems for UK clients, priced as capped time and materials against a named team. If you want a specification and a costed plan before committing to a build, start with software development. If you need experienced engineers alongside a team you already have, hire a web developer covers that arrangement instead.

Frequently Asked Questions

How much does bespoke software development in London cost? London day rates typically run £550 to £1,100 for a small studio or mid-sized agency, £1,100 to £1,800 for a consultancy and £400 to £700 for a freelance contractor. On those rates a small internal tool lands around £45,000 to £70,000, a customer facing system with integrations between £200,000 and £350,000, and a complex platform between £1 million and £3 million. These are house estimates.

Why are London software rates higher than the rest of the UK? Pay is the visible part. ONS PAYE Real Time Information for July 2026 put median monthly pay at £2,642 across the UK and £3,116 in London, a premium of roughly 18 per cent. That gap compounds through employer National Insurance at 15 per cent above the £5,000 secondary threshold, and through central London property, where the 2026/27 high value business rates multiplier of 50.8p applies from a rateable value of £500,000.

Who owns the code when a London agency builds software for me? The agency does, unless the contract says otherwise. Section 11 of the Copyright, Designs and Patents Act 1988 makes the author the first owner, with an exception only for employees, and GOV.UK guidance confirms that a commissioner is not the first owner of a commissioned work. Section 90 requires an assignment in writing signed by the assignor, so a paid invoice transfers nothing on its own.

Should I take a fixed price or time and materials? Fixed price transfers real risk and is worth a premium when the specification is detailed enough that a third party could price it identically. On a vague brief it becomes a fiction settled later through change requests, which favours the supplier. The practical middle ground is capped time and materials: an agreed rate, a named team, a not to exceed figure and a written change process.

Is a London agency worth it compared with offshore or nearshore? Sometimes. Nearshore Europe commonly quotes £250 to £450 a day and South Asia £120 to £300, against £550 to £1,100 in London, but the saving is on rate rather than on effort. Distributed delivery needs more precise specifications and absorbs review latency. Compare London with the rest of the UK first, at roughly £400 to £750 a day with full working overlap.