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UK

Legacy System Modernisation for Fintech and Financial Services

Refactor or migrate outdated financial systems to modern, cloud-native platforms without data loss or downtime. Regulation-ready architecture built in from day one.

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Trusted by enterprises, scaleups and startups

  • British Gas
  • Lafarge
  • NHS
  • cinch
  • Bridgestone
  • Dole

WHAT YOU GET

Built around how your business works

  • Monolith to microservices migration with zero transaction downtime for live trading or payment systems
  • Audit trails and compliance as code built into the new architecture, not bolted on afterwards
  • Data migration verified for accuracy and integrity before cutover
  • Phased rollout option: run old and new systems in parallel until stability is proven
  • UK-based delivery with nearshore support from Spain and Ukraine for continuity
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Financial services depend on systems that handle transactions, settlements and regulatory reporting. When those systems were built 10 or 15 years ago, they often run on monolithic architectures that make adding features, patching security issues or scaling painfully slow. A single bug affects the whole system. Compliance updates mean redeploying everything. Data lives in silos, making audit trails hard to assemble. CTOs and IT Directors face a choice: keep patching an increasingly fragile codebase, or rebuild. The cost of staying put usually exceeds the cost of moving.

01

Why Legacy Fintech Systems Become Unsafe and Slow

02

Our Approach to Safe Migration in Regulated Environments

We start by understanding your current system's business logic, data flows and regulatory obligations. We map what must never break (transaction integrity, audit trails, KYC data) and what can be refactored safely. Then we design a modern stack that treats compliance as a first-class concern, not an afterthought. Microservices let you deploy payment logic separately from reporting or customer onboarding. Cloud-native infrastructure scales with demand. We run the old and new systems side-by-side during transition, comparing outputs to catch any drift. Your teams stay in control; we execute the plan.

Avoiding Common Migration Pitfalls

Legacy software modernisation fails when teams rush cutover, lose data in translation, or discover compliance gaps after go-live. We prevent this by stress-testing the new system against real-world load before switching traffic. We validate that every transaction, every regulatory report, every audit entry matches the old system. We keep detailed logs of what changed and why. If an issue appears post-cutover, we can revert in minutes, not days. Operations Directors know exactly what they are getting and when.

CASE STUDIES

How we've transformed enterprises, SMEs and startups

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ABOUT US

Read our story

Founded in 2007 as a dedicated IT consultancy, Evolved Ideas has grown into a team of over 100 professionals, with a head office in Leicester and development hubs in Eastern Europe and Spain.

Read more
19+
Years in business
200+
Successful projects
100+
Developers, designers and analysts
100+
Satisfied clients
  • Clutch Top Software Developers Leicester 2024
  • Clutch Global Fall 2024
  • UK Fintech Awards 2021 — Winner
  • UK Digital Technology Leaders Awards 2018

WHAT OUR CLIENTS SAY

The team at Evolved Ideas work with us as extended team members, and very much as part of our team. They have just completed a major milestone in our development, going live with our new loan management platform, and we couldn't be happier.

Kate Kennedy

OUR EXPERTISE

What we build

Over 17 years building custom software and mobile applications, and leveraging AI and ML to build the software you'll need next.

See it in the case studies
  • SaaS applications
  • Web-based portals
  • Custom B2B software
  • Native iOS applications
  • Native Android applications
  • Cross-platform mobile apps
  • White-label software
  • AI integration
  • Machine Learning

LOCAL INSIGHT

Working with businesses in the UK

Fintech and financial services in the UK operate under FCA, PSD2 and anti-money laundering rules that demand immutable audit trails, secure transaction processing and instant regulatory reporting. Legacy systems built before these rules were codified are often non-compliant or rely on manual workarounds that slow you down and create risk. Modernisation to cloud-native microservices with compliance as code lets you meet regulatory obligations at scale without overhead. Evolved Ideas' approach ensures your new system is audit-ready from day one, with clear data lineage and tamper-proof logs that regulators expect.

Where our teams sit

  • LeicesterHead office, UK delivery
  • Gran CanariaEvolved Ideas Spain
  • KyivEngineering hub
Meet the team

OUR PROVEN PROCESS

From first call to ongoing support

Our process has guided startups, scaleups and enterprises from concept to reality, and continues after launch.

  1. 01

    Discovery

    A free 30-minute consultation followed by a stakeholder workshop, where we listen to your challenges, validate assumptions and build an outside-in view of your situation.

  2. 02

    Plan & design

    We scope the project, define milestones and deliverables, then research your market, wireframe the UX and prototype the UI so the direction is agreed before a line of code.

  3. 03

    Build

    We assemble your dedicated team, establish reporting and work in iterative Scrum sprints, delivering a working MVP or proof of concept you can test with real users.

  4. 04

    Launch & support

    We ship, sign off, and keep your product current through our support service or a permanent extended team as your business evolves.

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OUR SOLUTIONS

We build solutions for your business challenges

Technology is more than just code — it's a tool for solving real business challenges. Whichever route fits your stage, the same team delivers it.

Bespoke Software

With your long-term goals in mind, we help you choose the technology you need and develop a tech roadmap based on industry trends, emerging tech and your business requirements.

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MVP Ideation & Validation

We have years of experience building proof of concepts and MVPs. We will take you from testing viability to building an MVP to validate your hypotheses.

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Application Support

Tier 1 customer support, Tier 2 technical support and Tier 3 development support for applications and legacy software, delivered by our engineering teams.

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Development Teams

If you need to build an IT team from zero or need staff augmentation, we can build the team you need — developers, designers, analysts and even fractional CTOs.

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FAQ

Questions we hear most often

Still unsure how this would work for your business?

Ask us directly
How do you prevent data loss when migrating a live transaction system?

We run both systems in parallel for a defined period, routing a percentage of real traffic to the new system and comparing outputs. This catches data mapping errors before full cutover. For critical systems, we validate every transaction record, settlement entry and audit log matches between old and new. We maintain detailed rollback procedures so if issues emerge, you can revert within minutes without losing a single transaction.

Can you modernise systems that need to stay compliant during migration?

Yes. That is the core of what we do in fintech. We design the new architecture to meet FCA, PSD2 and AML requirements from the start, not retrofit them. Audit trails, immutable logs, secure key management and transaction integrity are built into the code. We document every change for compliance teams and conduct testing that shows the new system meets all regulatory obligations before you switch.

What happens if the legacy system is tightly coupled to third-party APIs or payment processors?

We map all external integrations early and build adapters in the new system that maintain the same contracts. Payment processor APIs, settlement networks and reporting systems connect to the new architecture exactly as they did the old one. This means no third-party changes are needed, and you can migrate without coordinating with external partners. We test all integrations in a sandbox before cutover.

How long does a monolith to microservices migration typically take?

Timeline depends on codebase size, complexity and your tolerance for parallel running. A medium-sized fintech platform might take 4 to 8 months from design to full cutover. We break work into phases so you see value early: first APIs go live, then reporting, then user-facing features. This approach also reduces risk because each phase is smaller and easier to validate.

Who do we work with at your team, and how do you ensure continuity?

You have a named lead who owns the project end-to-end and reports to your CTO or IT Director weekly. Our UK-based delivery team owns architecture and design. We use nearshore engineers from Spain and Ukraine for implementation and testing, with full timezone overlap so progress is visible daily. This structure keeps decisions fast while giving you the depth of expertise fintech demands.

What if we need to add new features during the migration?

We design the new system to absorb new features as part of the build, not after. A microservices architecture actually makes this easier because feature work happens in isolated services. We prioritise critical compliance features and security improvements first, then layer in business features once the core is stable. You do not have to pause innovation while modernising.

EXPLORE MORE

Related solutions

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NEXT STEPS…

Ready to bring your ideas to life?

Book a free 30-minute discovery call with our team — we'll understand your objectives and advise how bespoke software, MVP development, or an extended team can help your business.

Book a free discovery call