Reduce Costs with Incremental App Modernization

Cutting legacy costs may be achieved by removing duplicate software, eliminating payments for infrastructure licenses, offshoring some tasks without sacrificing productivity, and redeploying workforce. However, the key question is there a strategic approach to digital transformation that allows CIOs to reduce costs in the process of app modernization?

Incremental Application Modernization

Why Incremental Application Modernization Works

Incremental modernization lets you upgrade legacy systems without the pain and risk of a full rewrite. It's ideal when budgets are tight but progress can't wait.

Application modernization can be achieved with less funding or a full system migration to the cloud. Begin with the most critical areas that deliver quick wins, then build on that success.

Even complex on-premises applications can be modernized step by step, often yielding faster results with less disruption than major rewrites.

• Low‑risk modernization: Uses APIs, microservices, and cloud platforms to update core functionality incrementally.
• Reduce technical debt: Each update phase removes legacy code, modernizes your tech stack, and moves toward cloud readiness.
• Business‑driven roadmap: Activities are chosen by complexity, cost, and impact, delivering quick wins and stakeholder confidence.

This systematic and fact-based method focuses on modifying organization-critical applications through a series of smaller, well-defined projects that require fewer resources. Each improvement builds on the last, helping your team to recognize value quickly and adapt at its own pace.

"An iterative light‑weight modernization approach that is informed by data, and driven by business value and priorities, is the ideal approach for CIOs to get over the modernization hurdle."
— Ted Tritchew, CTO Cloud Consulting IBM Canada

01. Use APIs to Extend Legacy Systems Without Downtime

Why this matters:

API-based modernization lets you integrate new cloud technologies into existing systems keeping everything up and running.

Many legacy systems can't be replaced all at once. Modernizing applications can't pause business. Waiting for a new system while relying on the old one isn't practical. Benefits from modernization must be seen in months, not years, preventing team exhaustion and reducing anxiety within the organization.

We prioritize mission‑critical applications when designing APIs to ensure that business operations remain uninterrupted during the modernization process.

An API-first approach is the solution. We design custom APIs specifically for your system's critical components and integrate them with cloud-managed or cloud‑native solutions, enhancing legacy component capabilities.

New features roll out continuously with no interruption to service.

Many current integration software programs require legacy application modernization to support hybrid cloud environments and updated data flows. These platforms often rely on outdated middleware, including ETL tools, ESB frameworks, or point-to-point coding, is inflexible, expensive, and poorly suited to integrate modern cloud platforms with on-site systems. Sometimes, it's also necessary to identify and remove redundant integrations as well as reduce the scaffolding code.

Our app modernization engineers design and deploy secure integration pipelines that connect legacy applications with mobile, social, IoT, big data sources. Using API capabilities of modern integration platform as a service (iPaaS), we enable seamless interoperability - inside and outside your corporate firewall.

02. Move Customizations to Microservices — Keep the Core Stable

Why this matters:

Modernizing legacy apps often starts by isolating business logic - microservices make this possible without overhauling the entire system.

When migrating legacy systems, isolating customizations into microservices reduces complexity while preserving the integrity of your core system.

Instead of rewriting your entire system, you can isolate the features that are unique to your business and move just those into microservices.

That makes it easier to update or replace parts of the system without affecting everything else.

Since microservices can be deployed on their own, development teams can work on different parts of the system at the same time and release changes faster - accelerating app modernization.

Each service scales separately and consumes only the resources it needs, so you only pay for what's used. This makes it easy to integrate with managed services and avoid overprovisioning.

Isolating custom features this way also improves application security, simplifies maintenance and troubleshooting.

03. Build a Global Platform with Local Customization

How can enterprises balance consistency and localization?

To support regional expansion, businesses need consistent and adaptable systems. A modular platform gives you a shared core while letting each location customize to fit local needs - driving effective application modernization at scale.

Large companies want one shared backbone - covering essentials like product workflows, data security, and user authentication - so every team works from the same foundation. But each region has its own context: different languages, taxes, currencies, or marketing approaches. Localized modules can plug into the shared core to handle those needs,supporting modernizing applications across markets..

Technically, this means using modular architecture or microservices, so local modules can be updated or scaled independently without impacting the global system, leveraging the power of cloud computing and hybrid cloud environments.

These modules "talk" to the core through APIs, ensuring data and workflows stay in sync no matter where they're deployed.

The global core can be updated without disrupting local modules. So no matter the region, your team and users get the same smooth experience.

And if a law or market condition changes in one country, you can tweak just that local module - without touching the rest of your platform.

Meanwhile, shared features stay consistent and centrally maintained, so you don’t waste time rebuilding the same thing twice.

04. Modernize Critical User Journeys First

Where should you start modernizing for maximum impact?

Not all of your system requires immediate upgrades. Start with the workflows your users rely on most - that’s where modernization drives customer experience, productivity, and ROI - rather than covering the entire application at once.

Some parts of an application matter more than others. A critical user journey is a workflow that directly affects how customers or employees use your product like creating a project, submitting an order, or assigning a task.

If that journey is slow or outdated, users feel it immediately. Fixing just this one area can make the whole system feel faster, smarter, and more modern - even if the backend is still partially legacy.

By narrowing scope to specific workflows, you limit risk while maximizing business impact: faster time to market, lower technical debt, and improved business processes.

The risks associated with the modernization are easier to manage because the scope is limited to specific, well-defined areas of the application.

In contrast, arbitrary modernization - updating large parts of the system because they "look" outdated - can consume time and budget without delivering proportional benefits. Not all components are tied to core operations or customer experience. By concentrating modernization efforts, we align cloud technologies and hybrid cloud investments with measurable business objectives.

05. Migrate Non-Differentiating Functions from Core App to Specialized 3-Party SaaS/PaaS

What to offload - and why it matters:

Not every function needs to live in your core application. Reporting, billing, or authentication can often be migrated to cloud platforms like SaaS and PaaS to save costs and speed up delivery supporting application modernization.

While SaaS usually replaces a particular function or application entirely, PaaS provides the building blocks that allow you to more easily develop and manage your own custom applications.

For instance, if your in-house application has a reporting feature that requires a specific database and server setup, rather than maintaining this internally, you can offload this to a PaaS solution that provides the necessary database and server resources. This allows your team to focus solely on business logic and user interface of the reporting feature itself.

Maintaining in-house solutions for non-core functions can be expensive. By moving non-essential tasks to third-party services, a business can focus more on what it does best, whether that's product development, customer service, or another core competency, while ensuring predictable cost optimization.

Third-party solutions are plug-and-play to accelerate development cycles and help get products or features to market faster. 

SaaS and PaaS solutions are generally built to be scalable, allowing companies to easily expand or contract usage based on needs, without the complex and costly process of altering in-house systems. 

Third-party providers often invest in application security and compliance measures, and meet industry standards. 

Using third-party solutions means you don't have to worry about the upkeep of the software. Updates, security patches, and new features are handled by the service provider.

Belitsoft helps you approach cloud migration incrementally - without disrupting core business operations. From wrapping legacy systems with APIs to offloading non-core functions to SaaS or migrating business-critical workflows to the cloud, our application modernization services guide every step. Contact our experts.