Modernization & Quality
Make the system you already have safe to change again
Legacy modernization, quality engineering, test automation, application security and managed support — delivered incrementally, without a big-bang rewrite.
What this practice covers
The problem
What usually brings people here
If two or more of these describe your situation, they are probably the same underlying problem.
Small changes carry unreasonable risk
Without tests or clear boundaries, a one-line fix can break something unrelated, so the team slows down defensively.
Knowledge left with the people who wrote it
The original engineers have moved on. Behaviour is documented only in the code, and nobody is sure which parts are still used.
A rewrite was attempted and stalled
A parallel rebuild ran out of budget before it reached parity, leaving two systems to maintain instead of one.
Security findings arrive faster than fixes
Scanner output piles up without triage, so genuine issues sit in the same queue as noise.
Our approach
How we run modernization & quality work
Modernization fails when it is treated as a single event. We work in slices: pick a bounded capability, characterise its current behaviour with tests, move it, verify, repeat. The system keeps running and stays releasable throughout.
The first goal is not new technology — it is confidence. A safety net of tests around current behaviour is what makes every subsequent change cheap. Without it, modernization is just a slower rewrite.
We are candid about what should not be modernized. Some systems should be left alone, wrapped behind an API, or retired. Recommending that is often the highest-value thing we do.
Capabilities
What we actually do
Each capability below is a service you can engage on its own or as part of a broader programme.
Legacy Modernization
Incremental migration of ageing systems using the strangler pattern — new capability built alongside the old, traffic moved gradually, and the legacy path removed only once the replacement is proven.
- Codebase and dependency assessment with a risk-ranked plan
- Characterisation tests capturing current behaviour before changes
- Strangler-pattern extraction of bounded capabilities
- Data migration with reconciliation and verified rollback
- Framework and runtime version upgrades
Quality Engineering
A quality strategy that fits how your team works: a sensible test pyramid, clear ownership, and pipeline gates that catch problems where they are cheapest to fix.
- Test strategy across unit, integration and end-to-end layers
- Quality gates and coverage policy in CI
- Defect analysis to find and fix systemic causes
- Release readiness criteria agreed with product
Test Automation
Reliable automated suites that engineers trust. A flaky suite is worse than no suite, so stability is treated as a first-class requirement.
- End-to-end coverage of critical user journeys
- API contract and integration testing
- Visual regression and accessibility checks
- Performance and load testing against realistic data
- Flake detection, quarantine and root-cause fixes
Application Security
Security work integrated into development: threat modelling, code review, dependency management and remediation prioritised by real exploitability.
- Threat modelling of authentication, authorisation and data flows
- Static and dependency analysis wired into the pipeline
- Manual review of authentication, session and access control logic
- Prioritised remediation plan with fixes, not just findings
- Secure coding guidance and team enablement
Managed Product Support
Ongoing operation of a live product: monitoring, incident response, dependency upkeep and a steady flow of small improvements.
- Agreed response expectations by severity
- Proactive monitoring and alert triage
- Dependency and security patch management
- Monthly reporting on incidents, changes and system health
Use cases
Situations we are asked about most
A monolith that has become one deployment unit
Extracting bounded capabilities behind clear interfaces so teams can release independently, without committing to microservices everywhere.
An application on an unsupported framework version
A staged upgrade path with characterisation tests at each step, keeping the product releasable throughout.
A test suite the team has stopped trusting
Stabilising flaky tests, removing low-value ones, and rebuilding coverage where it actually prevents defects.
A security questionnaire from a large customer
Reviewing the application against the questions being asked, fixing what matters, and documenting the controls honestly.
A product with no in-house team left
Taking over operation, restoring monitoring and documentation, and keeping it healthy while a longer-term plan is decided.
Deliverables
What you get, concretely
Everything below is handed over as part of the engagement, not sold separately afterwards.
- Assessment report with a risk-ranked modernization roadmap
- Characterisation test suite covering current behaviour
- Migrated capabilities running in production with rollback available
- Automated test suites integrated into CI with flake monitoring
- Security findings triaged by exploitability, with fixes applied
- Updated architecture and operational documentation
- Support agreement with defined response expectations
Delivery process
Assess
Review the codebase, dependencies, data model and operational history to establish what is risky, what is used and what can be retired.
- Assessment report
- Risk register
- Retirement candidates
Stabilise
Add monitoring and characterisation tests so current behaviour is captured before anything moves.
- Test safety net
- Monitoring
- Baseline metrics
Plan slices
Break the work into independently deliverable slices, each with its own value and rollback path.
- Slice plan
- Sequencing
- Success criteria
Migrate incrementally
Build alongside, shift traffic gradually, verify against the old path, then remove it.
- Migrated capabilities
- Traffic shifting
- Verification reports
Harden
Security review, performance validation and operational readiness for each migrated slice.
- Security report
- Performance results
- Runbooks
Operate
Ongoing support, monitoring and a continuing flow of improvements — or handover to your team.
- Support arrangement
- Monthly reporting
- Improvement backlog
Technology
The stack behind this practice
Selected per engagement. We recommend based on your team and constraints, not on preference.
Languages we modernize
- Java
- .NET
- PHP
- Python
- Ruby
- Node.js
- AngularJS
- jQuery
Target platforms
- TypeScript
- React
- Next.js
- Node.js
- Go
- Spring Boot
- .NET 8
Testing
- Playwright
- Cypress
- Vitest
- Jest
- JUnit
- pytest
- k6
Security
- OWASP ASVS
- Semgrep
- Snyk
- Trivy
- Dependabot
Data migration
- Debezium
- Flyway
- Liquibase
- Airflow
Security & quality
Non-negotiables on every engagement
- OWASP ASVS used as the review checklist rather than an ad hoc list
- Findings prioritised by exploitability and business impact, not scanner severity alone
- Secrets scanning across history, with rotation where exposure is found
- Access control tested explicitly, including negative cases
- Dependency upgrade policy with a defined response window for critical advisories
- Documented incident response process, rehearsed rather than filed
Related work
A worked example
An illustrative engagement showing how this practice runs end to end.
- LogisticsSample content
Modernizing a logistics portal without pausing operations
Incremental migration of a business-critical customer portal and driver workflow using the strangler pattern, with no cutover event.
- Next.js
- TypeScript
- Node.js
- PostgreSQL
Modernize Legacy Applications
Incremental modernization using the strangler pattern — assessment, a test safety net, capability-by-capability migration, and no big-bang cutover.
See the approachScale Engineering Capacity
Vetted engineers and managed pods integrated into your process, with a defined onboarding path and a clear replacement policy.
See the approach
Engagement options
How to engage this practice
Dedicated Developers
A team that needs specific skills and already has engineering management in place.
Individual engineers who join your team full time, work in your repository and your process, and report to your leads. You direct the work day to day.
- Managed by
- You
- Commitment
- Monthly, typically three months minimum
Team Extension
Scaling an existing team quickly while keeping product direction fully in-house.
A group of engineers integrated into your existing team structure. Your leads set priorities and run the process; we handle recruitment, retention, performance and continuity.
- Managed by
- You, with our engineering support behind the team
- Commitment
- Monthly, typically three months minimum
Managed Delivery Pods
Owning an outcome end to end when you do not have management capacity to spare.
A cross-functional pod — engineers, QA, design and a delivery lead — that takes a defined scope and runs it. You set priorities and review outcomes; we run the delivery.
- Managed by
- Xalicon
- Commitment
- Quarterly, aligned to a defined scope
Offshore Development Centre
Building a durable long-term engineering capability outside your home market.
A dedicated long-term team operating as your extended engineering function, with its own hiring plan, career development and delivery structure aligned to your organisation.
- Managed by
- Shared governance between your leadership and ours
- Commitment
- Annual, with a defined growth plan
Questions
Modernization & Quality — questions we are asked
Modernization & Quality
Start a modernization & quality engagement
Tell us the outcome you need. We will tell you what it takes, what it does not, and where we would push back.
Prefer email? contact@xalicon.co