Foundational alliance supports phased migration and hybrid architecture approaches for enterprises managing mainframe-dependent infrastructure
TOKYO, April 28, 2026 /PRNewswire/ — OpenLegacy Japan Co., Ltd. (Shibuya-ku, Tokyo; Country Manager: Masahiko Shimoyama) announced a strategic alliance with Deloitte Tohmatsu LLC, a member firm of the Deloitte Tohmatsu Group, to support the modernization of legacy mainframe environments across Japanese enterprises. The alliance combines OpenLegacy’s patented modernization platform technology with Deloitte Tohmatsu’s system consulting and implementation capabilities to deliver flexible, low-risk modernization services.
Under the terms of the alliance, Deloitte Tohmatsu will be responsible for upstream system design, leveraging OpenLegacy Hub to automatically generate digital services that bi-directionally connect legacy mainframe, midrange, and database systems with modern cloud and microservices environments. This approach supports the strangler fig pattern for incremental modernization without requiring changes to core mainframe code, allowing organizations to migrate function by function while maintaining continuity of mission-critical operations.
Background
“Japanese enterprises are facing a convergence of pressures that makes the status quo increasingly untenable,” said Masahiko Shimoyama, Country Manager of OpenLegacy Japan. “The biggest challenge in Japan’s ‘2035 Cliff’ is a critical shortage of skilled talent to bridge the gap between aging legacy systems and modern AI-driven technology. As the workforce shrinks, the loss of technical knowledge risks leaving outdated systems permanently unmanageable, leading to a fatal decline in global competitiveness.”
Japan’s Ministry of Economy, Trade and Industry has warned that continued dependence on legacy technical debt could result in significant economic losses as this specialized workforce retires. For organizations in financial services and other regulated industries, the scale and complexity of full system replacement presents significant operational, financial, and business continuity risks. Demand has grown for modernization approaches that allow organizations to transition in stages, or to operate legacy and modern systems concurrently, rather than undertaking wholesale migration.
Modernization Approaches Supported Under the Partnership
The partnership is structured to support two primary modernization scenarios, which can be pursued independently or in parallel:
Phased Migration – OpenLegacy Hub’s automated services generation enables bi-directional integration between new serverless Java environments and existing legacy systems at the functional unit level, without hand-coded bridges or proprietary middleware layers. By connecting individual components via microservices, APIs, and Lambda functions, organizations can migrate incrementally, beginning with peripheral systems and progressing toward core functions. This approach is designed to reduce migration risk, shorten implementation timelines, enable innovation during modernization, ensure full operational consistency, and minimize disruption to existing data integration specifications. Customers have reduced time-to-market for new services by up to 10x compared to traditional migration projects.
Hybrid Architecture (Coexistence) – In cases where organizations choose to retain mainframe infrastructure for core functions such as high-volume transaction processing, while migrating front-end or agility-dependent functions to cloud environments, the partnership supports concurrent operation of legacy and modern systems. Data integration between environments is managed through OpenLegacy’s API layer, allowing each system to operate according to its strengths. This model also reduces mainframe workload over time, with corresponding reductions in operational and infrastructure costs – with customers reporting cost reductions of 60% or more compared to maintaining traditional ESB and middleware stacks.
Deloitte Tohmatsu will further support full-stack migration scenarios using its proprietary innoWake™tool, which provides automated code conversion from COBOL to Java and covers applications, data, batch jobs, and online screens.
Strategic Context
Beyond near-term migration planning, the partnership addresses a structural barrier facing enterprises seeking to adopt AI and data-driven capabilities. Legacy systems that lack modern connectivity cannot readily expose data to AI pipelines or integrate with cloud-native tooling – an estimated 88% of enterprises report that core legacy data remains inaccessible to generative AI models due to proprietary system formats and the absence of standard interfaces. OpenLegacy Hub is designed to make legacy system data accessible to modern environments without requiring underlying system rewrites, delivering production-ready digital services in as little as hours and days.
OpenLegacy’s technology is deployed by a global roster of Fortune 500 clients across banking, insurance, retail, manufacturing, healthcare, government, and telecommunications. Reference engagements include Legal & General, which achieved 10x scalability improvements by adopting an AWS cloud-first strategy supported by OpenLegacy Hub – a deployment that also validated OpenLegacy’s position as a strategic partner within the AWS Partner Network – and AIG, which reduced claims payment processing time from eight days to minutes after exposing core insurance logic as digital-ready APIs through the platform.
Deloitte Tohmatsu’s Application Modernization Studio Tokyo, established in April 2025 as the firm’s fifth global modernization center, provides a hands-on environment where enterprise IT and DX leaders can evaluate modernization approaches prior to implementation.
OpenLegacy Japan is the Japanese subsidiary of OpenLegacy, a software startup headquartered in New Jersey, USA. Leveraging OpenLegacy’s patented technology, the company provides solutions tailored for the Japanese market that rapidly, securely, and efficiently generate APIs (Application Programming Interfaces) to seamlessly connect mainframe, midrange, and database systems – which run on enterprise core systems – with cloud and microservices-based operating environments.
Media Contact:
Randy Fox
Extra Mind PR
randy@xmind.co.il
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