What is legacy system modernisation?

It's a plan for your whole software estate, not one app. We work out which legacy systems to leave alone, rehost, replatform, refactor, rebuild or replace, then sequence the work by what pays back soonest and what's riskiest to leave. You end up with a costed roadmap, not a rewrite you can't afford.

How much does legacy modernisation cost?

The assessment is £5,000, fixed — your estate inventoried and a costed roadmap you keep. Delivery is separate and starts from £15,000, phased so you fund one move at a time. We agree every price before work starts, and the roadmap is yours whether you build with us or not.

What are the 6 R's of application modernisation?

Six options for each system: retain (leave it as is), rehost (lift and shift to new infrastructure), replatform (small changes to modernise it), refactor (rework the code), rebuild (start again), or replace (buy something off the shelf). Most estates need a mix — the skill is matching the right R to each system, which is what the assessment does.

Do we have to rebuild everything?

No — and usually you shouldn't. A full rebuild is the most expensive, riskiest option, so we only recommend it where nothing cheaper will do. Plenty of systems just need rehosting or a replatform, and some are best left exactly as they are. The roadmap tells you which is which.

How is this different from rebuilding a single app?

A single-system rebuild scopes one app you've already decided to replace. This is a step earlier and wider: it looks across your whole estate and decides which systems to modernise at all, and in what order, before you commit to rebuilding anything. If you already know the one system to rebuild, that's rebuild discovery — this is for when you're not sure where to start.

Legacy System Modernisation UK

Every step, with a team who's done it before

Legacy systems rarely fail all at once — they get slower, riskier and more expensive to run until something forces the question. We start where that hurt is sharpest, assess the whole estate around it, and hand you a roadmap that fixes the worst first. You decide what happens next.

Book a free 20-minute consultation

A free call about where it hurts

We start with a free 20-minute consultation to find where your legacy estate is actually costing you — the system that keeps breaking, the one nobody can safely touch, the licence renewal forcing a decision. That tells us whether a full assessment is worth your money.
The assessment: your estate, mapped

For £5,000 we inventory the systems in scope and rate each one — what it costs to run, how likely it is to fail, and how much of the business leans on it. We map the dependencies between them, so nothing gets modernised in an order that breaks something else.
The roadmap, yours to keep

You get a costed roadmap that applies the 6 R's system by system — retain, rehost, replatform, refactor, rebuild or replace — sequenced by payback and risk. It's board-ready and yours to act on, with us or any other team.
Delivery, phase by phase

If the roadmap is worth acting on, we deliver it in stages from £15,000 — highest-payback move first, run in parallel with the old system until it's proven, with milestone payments so you fund one phase at a time. If a system is best left alone, we'll say so.

Estates we've brought up to date

Three places where the old way had hit its ceiling: a UK energy supplier's sales cycle run by hand across disconnected tools, automated end to end for a 5x lift in lead capacity in three months; an events group's Pipedrive, SmartDocs and Xero joined so around 500 invoices a month stopped being typed by hand; and an automotive imaging operation whose manual photo checks couldn't keep up, replaced over several years with a computer-vision pipeline.

SBU

CodeLeap automated the full sales cycle for a client in the UK energy sector, from lead capture through to signed contract, increasing lead generation capacity by 5x in 3 months.
Read more
CRM & sales automation

CodeLeap automated contract management, sales pipelines and invoicing for a media group running exhibitions and events across the UK and US — replacing around 500 invoices a month raised by hand.
Read more
Vehicle imaging platform

An end-to-end vehicle imaging platform for a company in automotive photography. CodeLeap built the capture apps and the computer-vision pipeline that removes backgrounds, builds 360-degree spins and checks every image automatically.
Read more

See more case studies

Our approach

How the assessment runs — the method we use to turn a tangle of legacy systems into a roadmap you can fund.

Estate inventory

We list every system, integration and database in scope, because you can't sequence a modernisation you haven't mapped.
Risk and cost rating

Each system gets a score for what it costs to run, how likely it is to fail, and how much it hurts the business when it does.
Business-value mapping

We weigh each system by the work it actually carries, so the effort lands where the business would feel the change.
The 6 R's decision

Every system is assigned one of retain, rehost, replatform, refactor, rebuild or replace, with the trade-offs of each spelled out.
Dependency mapping

We chart what talks to what, so nothing gets modernised in an order that breaks the system feeding it.
Payback sequencing

The roadmap orders the work by return and risk, so the first phase helps pay for the next rather than the cheapest job going first.
Phased delivery plan

The output is a staged plan you can fund one milestone at a time, with each phase proven before the next begins.
And much more

This is what comes up most often, not a limit. Bring us something that isn't on this list and we'll get up to speed on it — working with something new is the job, not an obstacle.

What our clients are saying

Real reviews from clients we have delivered for, on Clutch and elsewhere.

4.9 via Clutch

The enthusiasm, understanding of our mission, and passion from the first few minutes of the call were the deciding factors in choosing CodeLeap. Within 3 months of our app launching, we had over 1,500 downloads, appeared in leading publications from Forbes, The Metro, Marie Claire, Women's Fitness and many more, and started raising further investment.

Charlie CEO, Becon
They are incredibly diligent in the quality of work they produce, and go above and beyond when it comes to solving issues faced within the project, and to ensure we meet strict project deadlines. You never feel like you are one of many clients, and they ensure they are always there to help with any need you have, no matter how big or small.

Amelia Parmiter Marketing Manager, AWS - Marble
CodeLeap made me feel like my options were limitless in terms of what could be achieved, which was critical to me as we were creating something very unique. I'm glad I chose Codeleap over a large corporation as the personable approach resulted in a smooth and pleasant experience.

James CEO, Bearable
Working with CodeLeap was a very good experience from both a professional and personal point of view. These people know what they are doing and are both efficient and clever and made a good partner. I wouldn't hesitate to recommend CodeLeap.

John CEO, Neurometrics-Diab
CodeLeap adds so much value and goes above and beyond what I expected. CodeLeap's team is very flexible with all the different requests we've put in front of them. They've also been great with the whole business side of things, and being able to forecast for this industry is really helpful. Overall, I'm completely satisfied with their work — they've been incredibly helpful.

Johanne CEO, Cherry
Their flexibility and focus on quality were outstanding.

Mike Fenna CTO, Kite Insights
Marcelo has been wonderful throughout the process and we are very happy.

Amrit Director, Energy Company
Absolutely FANTASTIC. This is very much what I had in mind. We're very pleased with your team, thank you all very much.

Rich Director, Legal Company

See all reviews on Clutch

Recognised by the industry

Independent rankings from Clutch, The Manifest, SME News and the National Digital Awards.

Flexible, transparent pricing

Modernisation assessment

Estate reviewed, roadmap delivered
- Every legacy system inventoried and risk-rated
- What each one costs and returns today
- The 6 R's applied system by system
- A board-ready roadmap, sequenced by payback
- Fixed price, yours to keep and act on
£5,000
Book a free consultation
Phased delivery

Roadmap to live systems
- Your highest-payback move delivered first
- Rehost, replatform, refactor or rebuild, in turn
- Run in parallel with the old system until proven
- Milestone payments — pay as we deliver
- All code and IP yours on payment
From £15,000
Book a free consultation
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Any questions? We're here to answer

Everything you might want to know before starting a project with us.

It's a plan for your whole software estate, not one app. We work out which legacy systems to leave alone, rehost, replatform, refactor, rebuild or replace, then sequence the work by what pays back soonest and what's riskiest to leave. You end up with a costed roadmap, not a rewrite you can't afford.
The assessment is £5,000, fixed — your estate inventoried and a costed roadmap you keep. Delivery is separate and starts from £15,000, phased so you fund one move at a time. We agree every price before work starts, and the roadmap is yours whether you build with us or not.
Six options for each system: retain (leave it as is), rehost (lift and shift to new infrastructure), replatform (small changes to modernise it), refactor (rework the code), rebuild (start again), or replace (buy something off the shelf). Most estates need a mix — the skill is matching the right R to each system, which is what the assessment does.
No — and usually you shouldn't. A full rebuild is the most expensive, riskiest option, so we only recommend it where nothing cheaper will do. Plenty of systems just need rehosting or a replatform, and some are best left exactly as they are. The roadmap tells you which is which.
A single-system rebuild scopes one app you've already decided to replace. This is a step earlier and wider: it looks across your whole estate and decides which systems to modernise at all, and in what order, before you commit to rebuilding anything. If you already know the one system to rebuild, that's rebuild discovery — this is for when you're not sure where to start.