Legacy Currency Exchange Modernisation: 250 Stores Migrated to Cloud with Zero Business Disruption
Kubernetes-based architecture eliminates weekly restarts, enables horizontal scaling, and delivers proactive monitoring across retail FX operations
Executive Summary
Fexco is a global financial services and business solutions provider operating across 29 countries, delivering foreign exchange, corporate payments, tax-free retail services, and innovative technology platforms for regulated industries.
The Problem
Fexco’s Fusion currency exchange platform, serving 250+ retail locations across Ireland, the UK, and South Pacific, ran on a legacy on-premises system requiring manual restarts every two weeks, showing performance degradation, and approaching end-of-life. The technical debt threatened business continuity and regulatory compliance.
The Solution
Zartis designed and built a cloud-native replacement from the ground up on Kubernetes, architected for seamless dual-system operation during migration. The platform went live in Ireland in 2024, enabling migration of 250 stores without disrupting daily currency exchange operations.
The Outcomes
250 Irish stores migrated with zero business disruption during cutover
Weekly restart requirement eliminated: Legacy system needed manual restarts every 2 weeks; new platform runs continuously with stable performance
Horizontal auto-scaling enabled: Platform components scale based on load—impossible with legacy architecture
Proactive monitoring implemented: Integrated metrics, logs, and distributed traces catch issues before customer impact
All legacy vulnerabilities eliminated: Automated security scanning blocks deployments with critical issues
Infrastructure cost savings: Cloud migration avoided capital expenditure on end-of-life hardware replacement
Fexco provides financial services ranging from dynamic currency conversion and corporate payments to tax-free retail services. Their foreign exchange operations serve retail currency exchange bureaux and online platforms across multiple geographies.
About Fusion:
Fusion is Fexco’s foreign currency exchange product enabling bureaux de change and websites to sell currency across Ireland, the UK, and South Pacific regions (New Zealand, Australia, Fiji). The platform handles real-time currency pricing, transaction processing, and compliance requirements for regulated FX retail operations.
The Challenge
Fexco’s retail currency exchange operations depended on a legacy on-premises system showing critical signs of ageing:
Operational Reliability Crisis
- Manual restarts required every 2 weeks to maintain stability
- Performance degradation under normal load
- End-of-life infrastructure forcing decision between costly hardware refresh or complete modernisation
Business Continuity Risk
- 250+ retail locations across Ireland relied on the system for daily transactions
- System outages directly impact revenue—currency exchange bureaux cannot operate without the platform
- Regulatory compliance requirements for financial services demanded reliable audit trails and security controls the legacy system struggled to provide
Technical Debt Accumulation
- Manual maintenance burden consuming engineering time
- Non-scalable architecture limiting ability to handle peak transaction volumes during travel seasons
- Outdated technology stack making it difficult to attract engineering talent
- Security vulnerabilities in ageing dependencies creating compliance challenges
Market Expansion Constraints
- UK rollout planned for 2025 with ~300 additional stores—legacy system couldn’t support this growth
- South Pacific operations requiring reliable platform
- Competitive disadvantage without modern capabilities (mobile, real-time pricing, multi-factor authentication)
Why Traditional Approaches Weren't Working
Simply replacing hardware wasn't viable
The legacy currency exchange system’s architectural limitations, not just ageing hardware, created the operational burden. New servers would extend its life temporarily but wouldn’t address manual restarts, inability to scale horizontally, lack of modern observability, or missing capabilities like MFA.
Incremental modernisation was too risky
The legacy codebase had accumulated technical debt over years. Attempting to refactor piece-by-piece would take longer than clean-slate replacement, risk introducing new bugs into business-critical transaction processing, and fail to deliver modern cloud-native capabilities.
Technical complexity was too high
Fexco needed a partner who could design cloud-native architecture from first principles, build dual-system operation enabling gradual migration, maintain business continuity during cutover, and enable future UK and South Pacific expansion.
Why zartis
The Zartis Approach
Zartis owned the complete currency exchange platform redesign and rebuild, working as an embedded product engineering team.
The challenge wasn't just building a new platform, it was enabling seamless migration of 250 live stores without disrupting daily currency exchange operations. Zartis designed continuous data synchronisation between legacy and new systems using
Full Ownership from Day One:
Zartis took responsibility for the entire stack: Cloud-native Kubernetes architecture, frontend and backend applications, infrastructure provisioning, CI/CD pipelines, identity management, and observability.
Continuous Data Synchronisation:
Kafka message streaming for real-time transaction synchronisation, temporal workflows orchestrating complex data replication and reconciliation, gradual migration with immediate rollback capability and bidirectional synchronisation ensuring transactions processed on either system remained consistent.
Store by Store Cutover:
This meant stores could migrate individually, roll back if issues arose, and maintain full business continuity throughout the migration period—no "big bang" cutover risk.
Proactive Technical Debt Management:
Despite aggressive feature delivery, code quality remained top priority. Automated testing, QA processes, and a dedicated tech debt backlog ensured the platform remained maintainable as complexity grew.
Our approach
What We’ve Built & Delivered
Cloud-Native Kubernetes Infrastructure
Zartis designed and implemented the complete infrastructure from scratch:
Key Deliverables
Production-Grade Kubernetes Cluster
Running on Azure with multi-availability zone deployment for resilience
Terraform Infrastructure-as-Code
Enabling reproducible, auditable infrastructure provisioning
Container Orchestration
Providing automatic scaling, health checks, and self-healing capabilities
Network Architecture
With proper segmentation, firewall rules, and secure service communication
Why This Mattered
Kubernetes enables independent component scaling based on load, which was impossible with legacy monolithic architecture. The platform handles peak transaction volumes during holiday travel seasons without manual intervention.
Modern Application Stack
Zartis built both frontend and backend from the ground up.
Frontend
Angular-based web application with TypeScript
Responsive design
Real-time currency rate updates
Backend
Node.js microservices handling API orchestration and real-time event processing
Java Spring Boot services for transaction processing and business logic
MongoDB for flexible document storage of transaction records and audit logs
Kafka message streaming enabling event-driven architecture and system integration
Why This Mattered
Modern stack attracts engineering talent and enables faster feature development. Microservices architecture allows independent scaling and deployment—critical for maintaining high availability during updates.
CI/CD & GitOps Deployment
We enabled automated deployments from day one, not as an afterthought.
Deployment Automation:
- Jenkins CI/CD pipelines automating build, test, and deployment workflows
- ArgoCD GitOps deployment using Git as single source of truth for infrastructure and application configuration
- Automated testing catching issues before production deployment
- Security scanning blocking deployments with known vulnerabilities
Integrated Alerting:
Monitoring alerts elevate issues to DevOps, development, and product teams via Microsoft Teams integration, ensuring rapid response to production incidents.
Why This Mattered
Legacy system required manual deployments taking hours with high risk of human error. GitOps enables multiple deployments per day with confidence—accelerating feature delivery and bug fixes.
Production-Grade Observability
We baked full tracking and observability into the design before we started building.
Tracking Capabilities:
- Prometheus metrics tracking application performance, resource utilisation, and business KPIs
- Grafana dashboards visualising system health and operational metrics
- Distributed tracing following transactions across microservices to identify bottlenecks
- Centralised logging aggregating logs from all services for troubleshooting and audit
- Proactive alerting with integration to operational communication channels
Why This Mattered
Legacy system operated as black box. Teams only knew about problems when users complained. New observability enables proactive issue detection and resolution before customer impact.
Security Hardening
From automated scans and deployment blocking to data encryption and logs.
Security Capabilities:
- Automated vulnerability scanning in CI/CD pipelines
- Deployment blocking preventing releases with critical vulnerabilities from reaching production
- Container and infrastructure security baseline enforcement
- Immutable audit logs for regulatory compliance
- Encrypted data at rest and in transit
Identity & Access Management with MFA:
- Multi-Factor Authentication for bureau staff and administrators—capability legacy system couldn’t support
- Role-based access control ensuring appropriate permissions across user types
- Single Sign-On streamlining user experience
- Audit logging tracking authentication events for compliance
- Backward compatibility maintained during migration period, enabling seamless store cutover.
Why This Mattered
Legacy system accumulated security vulnerabilities over years. New platform started with clean slate and prevents vulnerability accumulation through automated scanning and deployment blocking.
Our approach
Key Technical Decisions & Trade-Offs
Clean-Slate Rebuild vs. Incremental Refactoring
Built entirely new platform using modern stack rather than attempting to containerise legacy codebase. Legacy system’s technical debt made incremental modernisation impractical—not containerised, architectural patterns incompatible with Kubernetes, missing foundational capabilities like observability and MFA.
Trade-off:
Dual-system operation added complexity during migration. However, this risk was mitigated through careful architecture (Kafka + Temporal synchronisation) and gradual rollout strategy.
Business Impact:
Ireland rollout completed successfully in 2024. Platform now ready for UK expansion (~300 stores) in 2025 without architectural rework.
Kafka + Temporal for Dual-System Synchronisation
Used Kafka message streaming and Temporal workflows to enable continuous data synchronisation between legacy and new platforms during migration.
Why This Mattered:
Migrating 250 live currency exchange bureaux couldn’t happen in single overnight cutover. Stores needed to migrate individually with ability to rollback if issues arose. Kafka and Temporal enabled real-time bidirectional synchronisation, ensuring both platforms maintained consistent state.
Business Impact:
All 250 Irish stores migrated successfully without business disruption. Approach validated for upcoming UK and South Pacific rollouts.
Microservices with Event-Driven Architecture
Built as event-driven microservices using Kafka rather than monolithic application. This enables independent scaling (transaction processing, currency rate updates, reporting scale based on different load patterns), resilience (service failures isolated), and integration flexibility (new services consume events without modifying existing services).
Trade-off:
Microservices add operational complexity. Distributed tracing essential for troubleshooting issues spanning multiple services.
Business Impact:
Platform handles peak transaction volumes without performance degradation. Components scale independently based on actual usage patterns.
GitOps with Security-First CI/CD
Adopted GitOps using ArgoCD for declarative infrastructure management, with automated security scanning that hard blocks deployments containing critical vulnerabilities.
Why This Mattered:
Git becomes single source of truth with complete audit trail. Automated synchronisation detects configuration drift. Security scanning prevents vulnerability accumulation that plagued legacy system.
Business Impact:
Faster, safer deployments with ability to rollback by reverting Git commits. Platform maintains clean security posture meeting financial services compliance requirements.
the results
Outcomes & Measurable Impact
Migration Success & Operational Excellence
Migrated successfully during 2024 rollout with zero business disruption
Store-by-store migration validated for upcoming UK (~300 stores) and South Pacific deployments in 2025
Manual restart requirement eliminated: Legacy system needed restarts every 2 weeks
Horizontal Auto-Scaling
Platform components scale up/down based on load
Proactive Monitoring
Integrated metrics, logs, and distributed traces catch issues before customer impact
Security & Compliance Transformation
Vulnerabilities Eliminated
All legacy vulnerabilities eliminated by starting with clean-slate platform
Automated Vulnerability Scanning
Preventing new security debt accumulation
Deployment Blocking
For critical vulnerabilities ensuring only secure code reaches production
Multi-Factor Authentication
Via Keycloak—meeting evolving financial services compliance requirements
Cost Optimisation & Development Velocity
Capital Expenditure Avoided
By migrating to cloud rather than replacing end-of-life hardware
GitOps Deployment Enabled
Multiple deployments per day vs. risky manual deployments requiring hours
Auditable Infrastructure Changes
Every modification tracked in Git history
Modern Tech Stack
Attracting engineering talent vs. legacy codebase
New Capabilities Enabled
Horizontal scaling
Scaling of individual components based on load patterns
Real-Time Currency Rates
Live rate updates without page refreshes
API-First Architecture
Enabling future mobile applications
Microservices Independence
Allowing teams to develop and deploy components without coordinating releases
What This Enabled Next
Strategic Value Beyond Initial Build
Multi-Market Expansion: UK rollout (~300 stores) and South Pacific markets deploying on same platform in 2025 with minimal customisation—legacy system couldn’t support this expansion.
Competitive Capabilities: API-first microservices architecture enables native mobile apps, real-time pricing integration, third-party partnerships, and advanced analytics previously impossible.
Engineering Team Evolution: Modern technology stack transformed Fexco’s ability to attract and retain engineering talent. Cloud-native skills, DevOps practices, and reduced maintenance burden now standard across organisation.
Client Relationship Evolution
What began as building a single aviation carbon platform has evolved into a strategic technology partnership. Zartis now maintains ongoing engagement with Fexco across multiple product lines, demonstrating sustained value delivery:
- PACE platform: Continued feature development, infrastructure management, security remediation, and operational monitoring
- Fusion (Foreign Currency Exchange): Cross-border FX application for retail currency sales
- Delivery Platform: DevOps infrastructure providing CI/CD across all Fexco IT projects
- Fexco Smart Assist: Azure OpenAI-based internal documentation assistant
Migrating Business-Critical Legacy Systems to Cloud?
If your organisation operates on ageing infrastructure facing technical debt, performance issues, and end-of-life hardware, we combine strategic architecture expertise with hands-on migration execution that maintains business continuity.