Mainframes have been the backbone of enterprise technology for decades. These systems have powered everything from banking transactions and insurance policies to airline reservations and government services. They’re reliable. They’re powerful. But they’re also old. And in a world where agility, scalability, and cost-efficiency have become necessities, legacy mainframes are starting to buckle under modern business demands.
If your organization is still running mission-critical applications on a legacy mainframe, it’s time to rethink the status quo. With the right mainframe modernization strategy, you can reduce costs, improve performance, boost agility, and position your business for long-term success.
Let’s explore how to modernize, migrate, and unlock the full potential of your core systems.
The Need for Mainframe Modernization
Maintaining legacy systems isn’t just expensive—it’s risky. These environments rely on aging infrastructure, limited integration capabilities, and highly specialized skills that are getting harder to find. As they grow increasingly inefficient, they hinder agility and scalability.
Modernizing your mainframe involves updating or replacing outdated applications with new, cloud-ready systems. This isn’t a superficial upgrade. It’s a fundamental transformation. With the right mainframe modernization strategies, businesses can achieve significant value and resilience.
Why Move to the Cloud?
As applications evolve, legacy systems become overloaded with data and business logic. Performance suffers, scalability becomes difficult, and even minor changes demand significant effort.
Cloud migration solves these issues. By shifting mainframe workloads to the cloud, organizations gain:
- Improved alignment between IT and business objectives
- Faster time-to-market
- Flexible resource usage
- Lower operational costs
The Challenges of Modernizing Legacy Mainframes
Of course, we get it—mainframe modernization isn’t easy. These systems have been deeply embedded into business processes over decades. Untangling them can feel like defusing a bomb while it’s still running.
Here are a few common mainframe modernization challenges:
- Complex interdependencies: Many mainframes are tightly coupled with other enterprise systems. Changing one piece can affect many others.
- Risk of downtime: Migration efforts can lead to data loss or service interruptions if not handled carefully.
- Lack of documentation: Decades-old systems often have minimal documentation, making them harder to analyze and refactor.
- Compliance concerns: Regulated industries need to ensure that new platforms meet strict security and privacy standards.
- Skill gaps: Modern developers are typically unfamiliar with legacy languages like COBOL, Assembler, PL/I, JCL, etc.
But there’s good news. With a structured mainframe modernization approach, the transition can be managed incrementally and strategically, reducing risk while unlocking significant value.
Modern Mainframe Modernization Techniques
Let’s explore some proven mainframe modernization techniques. These approaches allow organizations to update legacy systems while minimizing disruption and maximizing ROI.
1. Rewriting
Many legacy applications are built on monolithic codebases, which makes adding new features or rewriting parts of the system a real challenge. It’s not just about complexity—the real hurdle is finding developers who understand that old code and can work within the same programming language.
When that’s not feasible, the best path forward is often to rewrite the application entirely. This can be done manually or with automated tools, giving you a fresh, modern version that’s easier to maintain and scale.
2. Rehost or Re-platform
Rehosting is one of the most straightforward ways to get your applications into the cloud. It lets you move existing systems to a new environment without having to overhaul the whole codebase. Sure, you might need to tweak a few parts—especially where your app interacts with external tools like databases—but overall, the changes are minimal.
Re-platforming is similar, though it may involve a bit more fine-tuning to take full advantage of the new environment’s capabilities.
3. Replace
Sometimes, the best move is to retire the old application and switch to a ready-to-go solution. Think commercial off-the-shelf software or Software-as-a-Service (SaaS) platforms like Salesforce or a Policy Administration System (PAS). These come packed with useful features and are designed to get you up and running fast.
But before jumping in, make sure the solution integrates well with your existing systems. It should also have the user interfaces, dashboards, and reporting tools your team relies on. On the plus side, these platforms are typically quick to deploy, easy to validate, and come with built-in security and compliance support—assuming the vendor has a solid track record.
4. Retain
There are times when it actually makes sense to hold on to a legacy system. Maybe it performs a unique task that no other system can. Or maybe it’s part of a complex integration that would be risky to dismantle.
In some cases, businesses only need that legacy system to produce data now and then—for things like audits or compliance checks. When that’s the case, archiving it to low-cost storage and accessing it only when necessary, can be a practical solution. You get the functionality without the ongoing overhead.
5. Unified DevOps
Bringing DevOps into the legacy environment is a smart way to speed up modernization. Start with centralized code repositories and unified development environments. Add automated testing into the mix, and you’re setting the stage for smoother, faster releases.
This setup helps integrate updates into your main codebase more efficiently, leading to faster turnarounds and fewer bugs. Plus, by working in small sprints, your team can test changes in bite-sized chunks, lowering the risk of major failures and making the whole process more manageable.
6. Data Modernization
Data-heavy organizations—especially banks and financial institutions—often wrestle with rising costs from managing legacy datasets like VSAM, ISAM, IDMS, and IMS. These formats weren’t built for today’s fast-paced, cloud-connected world.
By migrating to modern database systems such as NoSQL or cloud-native platforms, companies can unlock major advantages. We’re talking about better agility, faster access to insights, and the ability to support emerging technologies like big data analytics, social media, and mobile-first services.
7. Optimize the Legacy Systems
Before diving into a full migration, it’s worth asking: are we using our existing resources wisely?
Monitoring and optimizing how your mainframe consumes MIPS (Million Instructions Per Second) can go a long way toward cutting costs. Keep a close eye on workloads, databases, and application code. With focused effort, organizations often see a 12–35% reduction in MIPS usage within six months.
That’s a meaningful win—and a great first step in your broader legacy mainframe modernization journey.
8. API-Enabled Access
Want your legacy applications to work with newer tools and platforms? APIs are your best friend.
By building APIs, you can create bridges between systems. This allows for data sharing, task automation, and even new customer-facing capabilities. To get there, legacy monoliths need to be broken down into smaller, independent functions—essentially microservices—that can be exposed and accessed via APIs.
It’s a powerful way to extend the life of your mainframe while making it play nicely with your modern digital ecosystem.
Benefits of Mainframe Modernization
Still on the fence? Here are just a few of the many mainframe modernization benefits:
- Enhanced Agility: Modern platforms support rapid development, deployment, and iteration—so you can launch new products and services faster.
- Lower Costs: Move from CapEx-heavy mainframes to OpEx-friendly cloud environments. Cut licensing, infrastructure, and support costs. A leading employee benefits company achieved 57% Cost Savings by Replatforming their Legacy Mainframe Applications to Azure Cloud.
- Stronger Security: Modern platforms offer robust built-in security features, automatic patching, and easier compliance with evolving regulations.
- More Automation: From DevOps pipelines to AI-driven monitoring, automation simplifies operations and frees your team for higher-value work.
- Future-Proof Technology: Modernized systems are easier to update, integrate, and scale—keeping your business competitive in a rapidly changing landscape.
How Hexaware Can Help
Information Services Group (ISG), a leading global technology research and advisory firm, named Hexaware a Leader in Application Modernization Services in the ISG Provider Lens™ Mainframes – Services and Solutions 2025 US Quadrant Report. At Hexaware, we make mainframe modernization simpler, faster, and more effective with powerful proprietary platforms: RapidX™, Tensai®, and Amaze®.
- RapidX™ uses Generative AI to analyze legacy systems, extract business logic, and create AI-powered digital SMEs that speed up development and reduce reliance on niche expertise.
- Tensai® streamlines IT operations with smart automation, real-time insights, and DevOps support, helping your teams release updates quickly, safely, and with confidence.
- Amaze® is our automation-first platform that drives seamless migration and transformation. From code discovery to replatforming, it minimizes disruption while maximizing speed and savings.
Together, these platforms empower you to modernize at your own pace, cut costs, and future-proof your business. We’re here to help you simplify the complex and unlock real value—every step of the way.
Ready to Modernize Your Mainframe?
The longer you wait, the harder and costlier it becomes to maintain a legacy mainframe system. But with the right mainframe modernization approaches, tools, and team by your side, you can take control of your future and accelerate your digital transformation.
At Hexaware, we specialize in tailored mainframe modernization services that meet your business where it is—and take it where it needs to go.
Let’s chart your modernization roadmap together. Your journey to smarter systems, faster innovation, and future-proof operations starts here.
