11 Leading Mainframe Modernization Companies to Consider in 2026
Successful mainframe modernization requires technical proficiency, deep domain expertise, and business focus. This list of 11 leading mainframe modernization companies is based on our market research to help you compare various vendors and choose the best one for your project and eliminate risk. Read on for more details.
Reliqsy
Reliqsy is a great choice for a risk-controlled transformation. Backed by an AI framework, Retrieval-Augmented Generation, and a coordinated Multi-Agent Swarm, it enables deep legacy system analysis without significant manual effort. Reliqsy automatically scans your code, detecting technical debt, undocumented business logic, and security gaps.In addition, AI agents generate cleaner code validated against the legacy app behavior. All the changes are implemented incrementally, protecting your operational continuity.
Corsac Technologies
Corsac dives deep into the roots of your technical stagnation to uncover what drains your business resources. After detecting code issues, security gaps, data inconsistencies, and integration limitations, they don’t force a risky rewrite of the entire system. They evolve the functional parts and make changes only where required.Thanks to automated CI/CD pipelines, the Corsac experts minimize downtime and operational risks while delivering changes independently, letting your team focus on core tasks.
Accenture
Providing end-to-end modernization services, this vendor ensures a gradual transition at your pace. Backed by AI-powered tools and expertise in various industries, they can be handle projects of any size and complexity. Whether you need to enhance performance, cut infrastructure costs, or scale with confidence, this company will deliver the necessary changes on time and within budget. The Accenture team is also strong in modernization consulting, enabling well-planned transformation with long-lasting results.
IBM
This top-rated vendor combines excellent technical skills and a strategic approach focused on new market opportunities and сlient’s revenue growth. By transforming a rigid, monolithic architecture into a reliable, cloud-ready, and flexible system, they enable faster delivery with lower costs. The IBM experts place special focus on security and compliance, which are usually vulnerable when it comes to mainframe software. By hiring IBM for consulting, you get a comprehensive system analysis with a detailed report and a clear modernization roadmap.
Luxoft
This company specializes in complex modernization projects, working with COBOL, Assembler, IMS, and JCL, and owns tools like compilers and code converters. Luxoft helps build cloud-ready architecture, preserving your business-critical logic. Its modernization services include legacy audit, application refactoring or replatforming, database migration, performance optimization, CI/СD pipeline setup, and strong automated testing. Luxoft enables fast, secure, and transparent mainframe modernization with long-term results.
Kyndryl
Kyndryl’s modernization approach is based on AIOps and generative AI, making processes faster and more efficient. Their mainframe product engineering services enable continuous transformation with measurable outcomes rather than one-time system updates. Depending on your project goals, you can opt for different migration levels, from rehosting to full off-mainframe moves. Another Kyndryl benefit is its stable partnerships with hyperscalers like Microsoft and Google Cloud.
Rocket Software
This company was recognized as a Challenger in the 2025 Gartner Magic Quadrant. For potential clients, it’s strong evidence of the vendor’s reliability and excellence in hybrid IT and innovation. They ensure a smooth modernization process with measurable outcomes by applying automation, modern DevOps practices, and predictive AI.
Rocket Software follows a security-first approach, providing clients with in-depth compliance evaluation and necessary enhancements.
CGI
Mainframe modernization by CGI is about transitioning to more agile and cost-efficient Unix and Linux platforms without risk of business logic disruption. Thanks to their client-centric approach and reliable strategies tailored to each project, they help achieve significant maintenance cost reduction and optimize resources for innovation. They’ve also established their own Global Competency Center for IT modernization to gather a specialized modernization team with top-notch expertise. Their M8 automated tooling helps derisk migration as well.
HCL Tech
This is one of the VMS companies providing enterprise-grade modernization. Thanks to the business-first approach, HCLTech prioritizes components that really require changes and preserves existing investments. Whether you need rehosting, replatforming, refactoring, or hybrid cloud integration, this team can handle projects of any complexity. They implement phased modernization with minimal disruption, applying industry-proven tools and frameworks (iLIT-DC, ADvantage Cloud, Automated Technology Modernization Accelerator, and Sketch).
Astadia
Astadia enables accelerated modernization utilizing tools like FastTrack Migration Factory. It helps automate almost every step, including legacy system audit, code conversion, database migration, testing, and moving workloads to modern platforms. As a result, Astadia accelerates project delivery, reducing operational costs and risks.
Combining the expertise of their seasoned developers and GenAI, they tackle complex modernization tasks with high accuracy and focus on business priorities.
Kumaran
Kumaran offers AI-powered mainframe modernization with zero-business logic loss. While GenAI enables accurate code generation across all layers and accelerated delivery, manual expert validation ensures every business rule is preserved. Their modernization platform is built on six core capabilities: automated source analysis, knowledge graph (Neo4j), GenAI-driven code generation, human-in-the-loop validation, batch & online coverage, and cloud-native deployment. Thanks to the NxTran accelerator, Kumaran experts make the modernization process smoother, faster, and more predictable.
Challenges
How to Choose the Best Provider Among Mainframe Modernization Companies
FAQ
What are the benefits of working with a specialized mainframe modernization company?
Specialized mainframe modernization companies possess proven expertise in both legacy and modern technologies and can preserve the original functionality. Such vendors understand all the challenges that companies face with legacy systems and help overcome them, preserving core business logic and security.
How should I choose the best mainframe modernization company?
Mainframe modernization goes far beyond simple code patches. It requires in-depth business focus and industry expertise. Look for the partner that can prove it through successful case studies and validated client reviews. Also determine whether the partner prioritizes security and meets modern regulatory standards.
How can I evaluate a vendor's modernization experience?
Top mainframe companies usually have a detailed portfolio that demonstrates measurable outcomes and clear business value. Check if the case studies highlight project scope, legacy stack, migration approaches, target architecture, and security standards. Customer reviews, especially those on trusted listings, can provide you with more insights, like the ability to deliver on time and within budget, and project management style.
How long does mainframe modernization take?
From 3–6 months to several years. It’s hard to provide a precise answer as the timeline depends on many factors. First of all, it’s about your legacy system complexity, integration requirements, and strategic goals. However, top mainframe vendors implement changes incrementally, so you can benefit from modernization from the early stages without waiting for the entire project to be completed.
What role does AI play in mainframe modernization?
The leading mainframe modernization solutions usually include AI to reduce manual effort and accelerate modernization activities. For example, AI can automate legacy code analysis, provide recommendations, build technical documentation, generate modern code, and test it. The combination of AI and human expertise for business logic validation can significantly minimize the risk of disruption and help avoid costly mistakes.