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CASE STUDY · MODERNISATION

Legacy system modernization without betting the business on a big-bang rewrite.

SECTOR · ENTERPRISE JAVA PLATFORMMODERNISATION

Illustrative scenario · Sector: Enterprise software, financial services, manufacturing and SaaS · Solution partner: Brandsmashers Tech

  • 6 → 2 wksTarget release cycle within 12 months
  • 14 → 8Target production incidents per quarter

01 · PROJECT OVERVIEW

Old technology is not the real problem.

Legacy applications often remain at the heart of critical business operations. The problem is not simply that the technology is old.

The bigger problems are slow releases, hard integrations, tangled modules, thin test coverage and a shrinking pool of engineers who know the system. A complete rewrite may sound attractive, but it can introduce significant technical and business risk.

OUR RESPONSIBILITIES
  • Assessing architecture, dependencies and business-critical paths
  • Choosing the highest-friction modules to modernise first
  • Establishing APIs and extracting capabilities incrementally
  • Improving CI/CD and measuring delivery and stability
WHAT IS SLOWING THE BUSINESS
  1. Slow release cycles and difficult integrations.
  2. High dependency between modules and limited test coverage.
  3. Production incidents, and few engineers familiar with the system.

02 · THE CHALLENGE

A monolith that resists change.

Consider a 10-year-old Java monolith with a 6-week release cycle, 14 production incidents per quarter and 8 high-change modules. Instead of rewriting everything, the strategy targets the two domains creating the greatest business and engineering friction.

  • PROBLEM 01Six-week release cycle

    Every change waits for a large, coordinated release, so the business waits too.

  • PROBLEM 0214 incidents a quarter

    Changes in one module break others, and fixes are slow to ship.

  • PROBLEM 03Eight high-change modules

    A few parts of the system absorb most of the change and most of the risk.

  • PROBLEM 04Big-bang rewrite risk

    Replacing everything at once would freeze features for years and put critical operations at risk.

Modernize what is slowing the business, not everything at once.

03 · THE APPROACH

Six steps, one domain at a time.

Incremental modernisation keeps the business running while the parts that hurt most are changed first.

  1. 01
    Architecture assessment

    Understand dependencies, traffic, modules and business-critical paths.

  2. 02
    Identify candidates

    Find the high-change, high-risk or high-value components to start with.

  3. 03
    Establish APIs

    Create clear interfaces between the existing system and new components.

  4. 04
    Extract incrementally

    Move selected capabilities without disrupting the entire platform.

  5. 05
    Improve CI/CD

    Introduce automated testing and deployment pipelines.

  6. 06
    Measure

    Track release frequency, incidents, recovery time and change failure.

THE DELIVERY FLOW, END TO END
  1. 1Assess
  2. 2Pick two domains
  3. 3APIs
  4. 4Extract
  5. 5Automate
  6. 6Measure

04 · RESULTS

The 12-month target.

The objective is a platform that is easier to change, without adding complexity it doesn’t need.

MODELED TARGETS
METRICBASELINETARGET
Release cycle6 weeks2 weeks
Production incidents14 per quarter8 per quarter
High-change modules8, all in the monolith2 extracted first
DeploymentLarge monolithBounded services
StrategyBig-bangIncremental
ILLUSTRATIVE OUTCOMES

This is a framework-based illustrative scenario; the figures are modeled targets, not client results. Financial, operational and client-specific outcomes require validation.

  • 2 weeksRelease cycleFrom 6 weeks.
  • 8Production incidents per quarterFrom 14.
  • 2 of 8High-change modules extracted firstThe two domains with the most friction.
  • 12 monthsTimeframeIncremental, with the platform running throughout.
  • Faster releases

    Smaller, independent deployments instead of one large release.

  • Fewer incidents

    Clear interfaces and automated tests contain the impact of change.

  • Lower risk

    No big-bang cut-over; each step is reversible and measured.

  • A platform that can keep changing

    The same approach extends to the next domains.

05 · DELIVERABLES

How Brandsmashers would build it.

  • Architecture assessmentDependency, traffic and module analysis of the existing system.
  • API layerClear interfaces between the legacy core and new components.
  • Incremental extractionStrangler-pattern migration of the highest-friction domains.
  • CI/CD and testingAutomated tests and deployment pipelines.
  • Delivery metricsRelease frequency, incidents, recovery time and change failure, tracked.
CAPABILITIES INVOLVED
Platforms
Java.NETDatabases
Architecture
APIsModularisationEvent-driven architectureStrangler pattern
Cloud
ContainerisationCloudDatabase modernisation
Delivery
DevOpsCI/CDAutomated testing

TAKEAWAYS

Why Brandsmashers.

  1. Start with the modules that change most and hurt most.
  2. Put APIs around the old system before taking it apart.
  3. Extract incrementally and keep the business running.
  4. Measure release speed and stability, not lines migrated.
APPLICABLE TO
  • Financial services
  • Manufacturing
  • Enterprise software
  • SaaS
  • Insurance

YOUR TURN

Modernising a legacy system?

Brandsmashers provides modernisation engineers across Java, .NET, cloud, APIs, DevOps, databases and application architecture.

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