FINANCIAL SERVICES
How Fleet Studio migrated a legacy core banking platform to cloud-native architecture serving 4M+ customers with zero unplanned downtime.
A major financial institution was running its core banking operations on a 20-year-old monolithic platform. The system processed $4B+ in annual transactions but was buckling under its own success. Release cycles took 6 months. Infrastructure costs were escalating 15% year-over-year. The platform couldn't support the real-time capabilities their customers demanded. Regulators were asking questions about operational resilience, and competitors with modern stacks were gaining ground.
Fleet Studio was engaged to lead a full platform modernization — from assessment through production cutover. We started with a comprehensive FRETA assessment to map every dependency, data flow, and integration point in the existing system.
The assessment revealed 340+ integration points and 12 critical batch processes that couldn't tolerate any downtime. We designed a strangler fig migration strategy that would incrementally replace the monolith without disrupting operations — essentially rebuilding the plane while it's flying.
Mapped 340+ integration points, identified 12 critical batch processes, quantified regulatory dependencies.
Designed strangler fig pattern with domain-driven decomposition to minimize cutover risk.
Executed 14-month migration in phases, validating at each stage before moving forward.
We decomposed the monolith into 47 microservices organized around banking domain boundaries. Each service owned a specific piece of the banking domain — account management, payments, lending, compliance — and could be developed, tested, and deployed independently.
47 domain-driven microservices replacing the monolith. Each service owns its domain, its data, its deployment schedule.
Active-active deployment across regions with automatic failover. 99.999% availability SLA baked into the infrastructure.
Apache Kafka backbone for real-time transaction processing. Replaced 30-second batch delays with sub-second event propagation.
During cutover, both systems ran in sync. Eliminated the riskiest moment in any migration: the switch-over.
Distributed tracing with OpenTelemetry. Custom SLO dashboards for every service. Automated incident response and remediation.
Built compliance into the architecture from day one. Audit trails, data residency controls, encryption at rest and in transit.
The entire system was designed not just for performance and scale, but for operational resilience and regulatory rigor. We knew that a single unplanned outage would erode trust with regulators and customers alike.
The new platform doesn't just meet the bank's current needs — it positions them for the next decade of innovation. Feature development went from a multi-quarter process requiring coordination across dozens of teams to something teams can execute independently.
Big bang migrations at this scale are too risky. By replacing the monolith incrementally, we maintained operational continuity and could validate assumptions at each phase.
Before we touched production systems, we built comprehensive monitoring and tracing. This investment paid dividends in confidence and speed throughout the migration.
We involved compliance and risk teams in architecture design, not after the fact. This prevented costly surprises and ensured the solution met regulatory expectations upfront.
The dual-write approach added complexity but eliminated the riskiest moment in any migration: the final switchover. The ability to validate both systems in parallel reduced cutover risk dramatically.
Organizing microservices around business domains, not technical layers, led to cleaner boundaries and made it possible for teams to move independently.
The technical migration was only half the challenge. We invested in training, new deployment processes, and cultural alignment that made teams comfortable with the new architecture.
Whether you're running on legacy systems or struggling with scalability, let's discuss your platform challenges. We'll assess your current state, identify the highest-impact modernization opportunities, and outline a migration strategy that works for your timeline and risk tolerance.