Legacy Decommissioning & API Modernization
A financial services organization sought to modernize
and decommission multiple legacy applications as part
of a broader digital transformation initiative.
Technology
Java 21, Spring Boot 3.x, AWS, Microservices architecture, RESTful APIs, GitHub, and CI/CD pipelines
Scope
Legacy Decommissioning and API Modernization
The Challenge
The client faced significant challenges in maintaining their aging infrastructure. Several applications required migration to modern platforms such as GitHub, Java 21, and Spring Boot 3.x.x. Additionally, dependencies on legacy APIs and databases needed to be resolved while ensuring minimal disruption to business operations.
A key challenge involved creating new APIs to replace deprecated services while ensuring seamless data access and integration. This required: Identifying and analyzing existing API dependencies to map out required replacements.
Developing modern, scalable APIs to support financial transactions, customer data management, and other core business functions. Coordinating with consuming application teams to facilitate smooth transitions from legacy to modern endpoints. The decommissioning efforts also required a structured approach to migrate and consolidate multiple consumers across different systems.
The Solution
York partnered closely with the client to execute a multi-phased modernization strategy that addressed both technical and operational needs. The engagement began with a comprehensive assessment of existing applications and API dependencies, allowing the team to identify required replacements and modernization paths. York then supported the migration of source code repositories to GitHub, aligning development workflows with modern DevOps best practices. To modernize the application stack, critical systems were upgraded from Java 17 to Java 21 and from Spring Boot 2.x to 3.x, improving performance, security, and long-term supportability. In parallel, York designed and developed new, scalable APIs to replace legacy services, supporting core financial transactions, data integration, and system interoperability. The modernization effort also included transitioning applications from on-premise environments to AWS-based infrastructure and implementing microservices-based architectures to improve scalability and resilience. Throughout the process, York emphasized standardization, documentation, and knowledge transfer to ensure long-term success beyond the engagement.
The Results
The modernization and decommissioning initiative delivered meaningful outcomes for the client, including reduced technical debt and the successful retirement of legacy applications and dependencies. By adopting modern frameworks, cloud infrastructure, and standardized development practices, the client improved system performance, maintainability, and security. Developer efficiency increased through streamlined workflows and improved tooling, while API transitions were completed without disruption to business operations. The result was a faster, more secure, and more scalable API ecosystem, positioning the organization to support future growth and continued digital transformation with confidence. By taking a thoughtful, structured approach to legacy decommissioning and API modernization, York helped the client move beyond short-term fixes and build a technology foundation designed for long-term impact.
