Services · Modernise

Modernisation that reduces risk instead of moving it somewhere new.

Legacy replacement projects fail when they try to rebuild everything at once against a system nobody fully understands. We work incrementally: understand the estate, carve out the parts that hurt most, prove the migration on real data, and keep the business running throughout.

Plan a modernise project Talk to someone

Problems we hear

If you recognise any of these, this is the right page

Our core system works, but changing anything takes months and nobody wants to touch it.
The people who built it have left and the documentation is out of date or absent.
We are paying for infrastructure and licences that the current architecture forces on us.
A vendor is end-of-lifing a platform we depend on and we have a hard deadline.
We have data in several systems that disagree with each other.

Outcomes

What you should have at the end

A documented estate: An accurate picture of what you actually run, what depends on what, and where the real risk sits.
Incremental delivery: Value released in stages rather than one high-risk cutover eighteen months from now.
Verified data migration: Migrations rehearsed against production-shaped data with reconciliation reports you can audit.
A lower cost of change: Measurable improvement in how quickly a change can go from request to production.

Capabilities

What Modernise covers

Each of these is a distinct piece of work with its own deliverables. They combine into engagements rather than being sold separately.

Legacy application modernisation

Replace or refactor an ageing system without stopping the business.

The problem

A big-bang rewrite requires you to freeze the existing system, understand it perfectly, and be right the first time. All three are usually false.

What the work involves

We start by making the existing system observable and testable enough to change safely. Then we carve functionality out incrementally — commonly with a strangler pattern behind a routing layer — so each slice can be released, measured and reversed. Where a rewrite genuinely is the right answer we will say so, with the reasoning written down.

Typical deliverables

Estate assessment with dependency and risk mapping
Modernisation roadmap sequenced by risk and value
Incremental migration with routing and fallback
Characterisation tests around the behaviour being preserved

API and integration engineering

Make systems talk to each other reliably, including the ones you do not control.

The problem

Integrations built as point-to-point scripts become the least reliable and least understood part of the estate, and they fail silently.

What the work involves

We design integrations with explicit contracts, idempotency, retry and dead-letter handling, and observable failure. Third-party dependencies sit behind interfaces so a provider change is a configuration decision rather than a rewrite. Every integration gets a connection-status view and a diagnostic path for support staff.

Typical deliverables

Documented API contracts and versioning policy
Signed, idempotent, replay-resistant webhook handling
Retry, dead-letter and reconciliation mechanisms
Integration monitoring and admin diagnostics

Data and platform migrations

Move data between systems with evidence that nothing was lost or corrupted.

The problem

Migrations are commonly validated by spot-checking a handful of records, and the discrepancies surface months later in a finance report.

What the work involves

We profile the source data first, agree the transformation rules explicitly including how to handle records that do not conform, and rehearse the migration repeatedly against production-shaped data. Every run produces a reconciliation report: counts, checksums, exceptions and the decisions taken on them.

Typical deliverables

Source data profile and quality assessment
Documented transformation and exception-handling rules
Repeatable migration tooling with rehearsal runs
Reconciliation reports and a rollback procedure

Application re-architecture

Change the shape of a system so it can absorb the next five years of change.

The problem

Systems accumulate coupling until a small business change touches a dozen modules and a release requires everyone to be available.

What the work involves

We identify the boundaries that actually matter to your business, separate them deliberately, and leave the rest alone. We are sceptical of microservice decomposition undertaken for its own sake: distributed systems trade a code problem for an operations problem, and that trade needs justifying.

Typical deliverables

Domain and boundary analysis
Target architecture with recorded trade-offs (ADRs)
Incremental refactoring plan
Deployment and release-independence improvements

Cloud-native transformation

Move to cloud in a way that reduces cost and risk rather than adding both.

The problem

Lift-and-shift migrations often produce a more expensive version of the same system, with new operational complexity and no new capability.

What the work involves

We assess each workload against a clear disposition — retain, re-host, re-platform, re-architect or retire — with the cost and risk of each recorded. We migrate in waves, with landing zones, identity, networking and cost governance established before the first workload moves.

Typical deliverables

Workload disposition assessment with cost modelling
Landing zone, identity and network foundations
Wave-based migration plan and execution
FinOps baseline and ongoing cost governance

Engagement models

How we can work together

Estate assessment

A fixed-fee assessment producing a documented picture of the current estate, its risks and a sequenced modernisation roadmap.

Best for: Organisations that know something must change but cannot yet justify a programme.

Fixed-scope milestones

Discrete migration or modernisation slices with acceptance criteria and fixed fees.

Best for: A defined migration with a hard external deadline.

Dedicated squad

A team embedded alongside yours for a sustained modernisation programme, transferring knowledge as it goes.

Best for: Multi-year programmes where your team must be able to continue the work.

Delivery process

How the work runs

01
Explore
Understand the estate, the pressure and the deadline.
02
Shape
Assessment, dispositions, sequencing and costed options.
03
Build
Incremental slices, each independently releasable.
04
Validate
Migration rehearsals, reconciliation and performance evidence.
05
Launch
Rehearsed cutover with a tested rollback path.
06
Operate
Run the new estate and retire the old one properly.

Technology approach

What we build with, and why

Assessment: Dependency analysis, runtime tracing and cost modelling before any code changes.
Migration patterns: Strangler routing, change data capture, dual-write with reconciliation, and read-replica cutover.
Data: Postgres, SQL Server and cloud-managed data services, with repeatable, version-controlled migration tooling.
Cloud: Azure, AWS and Google Cloud landing zones defined as infrastructure as code from the outset.

Security and quality

Non-negotiables

No migration goes to production without at least one full rehearsal against production-shaped data.
Every cutover has a written, tested rollback procedure before it is scheduled.
Behaviour being preserved is protected by characterisation tests written before the change.
Reconciliation evidence is produced automatically and retained for audit.
We record what we chose not to modernise, and why.

Investment

Starting points

Indicative bands, not quotations. What moves a project within — or outside — these ranges is scope, integration count, data quality and regulatory context.

Full pricing

FinOps / architecture review

£7,500 – £25,000

A focused assessment with findings and a prioritised plan.

Cloud or AI readiness

£10,000 – £30,000

Estate assessment, dispositions and a sequenced roadmap.

Cloud landing zone

£20,000 – £60,000

Identity, networking, security and governance foundations as code.

Application modernisation

£40,000 – £200,000+

Depends heavily on estate size, data volume and downtime tolerance.

All published figures are indicative and exclude tax, cloud and model usage, third-party licences and app-store fees. A price becomes an offer only when a person at NELLA Labs confirms it in writing.

Where this shows up

NELLA Labs product

Daju Verify

Onboard people and businesses with evidence you can audit.

Industry

Government and public services

Services that must work for everyone, and be defensible afterwards.

Industry

Financial services and fintech

Onboarding, money movement and controls that survive an audit.

Industry

Healthcare

Clinical safety, interoperability and data that cannot leak.

Frequently asked questions

Can you work with our existing engineers rather than replacing them?

That is usually the better outcome. Your engineers hold context we cannot buy. We typically work as an embedded squad, pairing on the difficult parts and leaving behind the tests, tooling and documentation that make the next change cheaper for your team rather than for us.

What if nobody understands the existing system?

This is common and it is not a blocker. We instrument the running system to observe what it actually does, write characterisation tests around the behaviour we need to preserve, and reconstruct the domain model from data and usage rather than from documentation that may be wrong.

How much downtime will a migration need?

We design to your tolerance rather than assuming one. Zero-downtime cutovers are achievable in most cases using dual-write and read-cutover patterns, but they cost more to build and test. We will price both options and let you choose with the trade-off visible.

Our vendor says only they can migrate our data. Is that true?

Occasionally, where a proprietary format genuinely has no documented export. Far more often the data is extractable through an API, a database replica or a supported export, and the constraint is contractual rather than technical. We will assess it and tell you which one you are facing.

Next step

Start a modernise conversation

The Project Architect will already know you came from this page, and will ask questions that fit.

Start the Project Architect Send a message