When companies start thinking about modernizing their applications, one concern pops up almost immediately: “Do we really need to rebuild everything from scratch?”
The idea of a complete rebuild can feel overwhelming, and for many teams it isn’t realistic either. A full rebuild brings high costs, long timelines, uncertain ROI, and the risk of disrupting daily operations.
The good news? There are cost-efficient alternatives that allow you to modernize step by step. With a phased approach to Application Modernization, you keep what already works, fix what blocks progress, and deliver visible value step by step.
Smart application modernization approaches
Modernization isn’t an all-or-nothing journey. Depending on your goals, existing architecture, and budget, you can choose different paths. Four of the most common and effective approaches are rehosting, replatforming, redesigning, and refactoring.
1. Rehosting
Rehosting, often called “lift-and-shift”, is the quickest way to modernize. It simply means moving your existing application to the cloud without rewriting code.
In practice
If you’re running an HR portal on on-premise servers, rehosting to AWS or Azure provides immediate benefits like automated backups, higher reliability, and better scalability without changing how the app works. Even at this stage, you can connect to cloud-native integrations such as monitoring, logging, or security tools that add value without touching your application logic.
Best fit
Rehosting is a smart move if you’re struggling with downtime, limited scalability, or high infrastructure costs. It stabilizes your environment and lowers IT overhead.
2. Replatforming
Replatforming takes rehosting a step further. While you still move the application to the cloud, you also make minimal adjustments to leverage cloud-native features.
In practice
A transport company moving its booking system to the cloud could also replace its outdated logging tool with a cloud-native monitoring solution. A common step here is adding an API layer around your existing app. This allows you to expose functionality to other systems, integrate new services, or prepare for modular upgrades later without deep rewrites.
Best fit
Replatforming is ideal if you want cloud benefits like monitoring, auto-scaling, or managed services, but only want to re-architect your system on a very small scale. It balances quick wins with slightly deeper modernization.
3. Redesigning
Sometimes, the back-end of a legacy application still performs well, but the user interface feels outdated or fails to meet accessibility standards. Redesigning focuses on front-end, creating a modern, inclusive experience while leaving the underlying logic largely intact.
In practice
Consider a banking app with a solid back-end but confusing navigation and poor accessibility for screen readers. By carrying out a front-end refresh with a modern design system, the bank can improve accessibility (e.g. colour contrast, keyboard navigation) and comply with the European Accessibility Act, all while preserving existing back-end functionality.
Best fit
Redesigning is the right choice when your users complain about usability, the conversion rates drop, or new accessibility regulations like the EAA apply to your business. It’s especially powerful when your back-end is stable.
4. Refactoring
Refactoring is about improving specific parts of the codebase without starting from scratch. It’s ideal when certain modules or features hold back performance, scalability, or integrations.
In practice
A logistics platform might keep its core intact but refactor the outdated reporting module to improve response times and reduce server load. Over time, this can evolve into a modular architecture, where different services (like reporting, payments, or user management) are separated into independent modules. This makes future changes faster, safer, and easier to scale.
Best fit
Refactoring makes sense when legacy or overly complex code creates bottlenecks, slows development, or blocks integrations with modern tools. It delivers targeted improvements without the disruption of a rebuild.
Tip: you don’t need to choose a single approach for your entire application. Often the best path is a mix. For example, rehosting first for stability, then redesigning the front-end while refactoring critical modules into a modular setup.
The concrete benefits of phased application modernization
Choosing phased modernization offers more than just cost savings. It’s about making modernization achievable and sustainable. Some of the key benefits include:
Lower risk: You avoid the “big bang” rebuild and instead improve in manageable steps.
Faster time-to-market: Ship improvements continuously, instead of waiting for the launch of a new version of your app.
Cost efficiency: Invest where it matters most instead of funding a full overhaul.
Business continuity: Keep operations running while modernizing in slices.
Flexibility: Prioritize the biggest pain points first, then tackle other areas when budgets or business needs allow.
Clear ROI Incremental wins make it easier to prove value to leadership.
How to approach phased modernization wisely
The smartest way to begin is with an Application Modernization assessment. This gives you a clear view of your current systems, highlights pain points, and helps define the right strategy, whether that’s rehosting, replatforming, redesigning, refactoring, or a mix of all four.
By mapping out your journey, you ensure that every investment contributes to long-term agility and future-proof technology, rather than just short-term fixes.
Beyond the first steps
Rehosting, replatforming, redesigning, and refactoring are effective first moves to stabilize and extend the life of your applications. They ensure your systems remain secure, stable, and relevant without requiring a complete rebuild.
But application modernization doesn’t end here. Once stability is achieved, you can move towards deeper transformation. A common next step is to gradually rewrite the parts of your application in a modular way and release them incrementally. This phased approach allows you to elevate your system to today’s standards without disrupting business operations. Over time, your application evolves into a modern, scalable, and future-proof platform. Built step by step, rather tan in a single risky leap.
