Your Complete Guide to Legacy System Integration [With Examples]

There are plenty of reasons why your company may still be using a legacy system. It’s the backbone on which your business runs. It’s what your team is familiar with. It’s what your customers or end users are familiar with.

But savvy tech leaders and executives are asking themselves a tough question right about now: Are those valid reasons? Your company may not be keen on updating legacy systems because of the expense, because it seems overwhelming, or because of lack of internal buy-in.

The truth is that outdated technology is costing your business, financially and otherwise. You’re losing your ability to innovate quickly and keep up with competitors, and putting your company at risk of security breaches and compliance risks. If you’re not leveraging the latest and greatest digital innovations — AI, cloud computing, automation, big data analytics — you’re falling behind your competitors.

Here’s the good news: You don’t have to scrap everything and implement a new system cold turkey. If you still rely on legacy infrastructure, you can interconnect it with modern platforms to get the best of both worlds without the need to discard existing systems entirely. This process is known as legacy system integration.

Let’s dig deeper into legacy system integration and find out why it’s important, the challenges businesses face when undertaking this kind of modernization, and how to make it work.

What Is Legacy System Integration?

Legacy system integration bridges the gap between older systems and today’s more modern applications by integrating the two. It’s not about replacing one system with another — it’s about creating a functionality where each component enhances the other, creating a seamless digital workflow tailored to your company’s unique needs.

Interconnecting legacy systems with modern technology paves the way for digital innovation without sacrificing the stability and reliability that you’ve come to know and love, thanks to your legacy system. Integrating legacy systems is often the driving force behind your company’s digital transformation initiative.

There are a few basic steps to approaching a legacy system integration:

1. Assessing legacy systems and identifying critical blockers. Your legacy modernization partner will analyze your legacy system’s architecture, data structures, and business requirements and identify legacy systems that act as blockers to business progress. Take the (fictional) XYZ Bank, for example. The company’s mainframe is a critical bottleneck. While essential for core banking operations, the system struggles to support modern payment methods like Zelle and Venmo, impacting customer service.
2. Choosing integration technologies. Next, you’ll work closely with your integration partner to choose the tools that will get the job done properly. XYZ Bank prioritizes building APIs to facilitate seamless data exchange between the mainframe and new banking technologies.
3. Planning for data migration. Your legacy modernization partner will strategize for the movement of data from legacy systems to modern platforms while minimizing disruption to operations and ensuring data integrity throughout the process. In XYZ Bank’s case, the strategy will be to modernize the mainframe with APIs while maintaining normal business and transaction processes.
4. Developing a timeline. This step involves mapping out key milestones and deadlines for the project. XYZ Bank sets a six-month timeline for API development and Zelle and Venmo integration.
5. Implementation. In the execution phase, chosen integration technologies will be put into action. Now, XYZ Bank’s newly built APIs are implemented to integrate the mainframe with Zelle and Venmo. 
6. Transferring knowledge. Your provider will impart essential skills and insights to your internal team, fostering self-sufficiency and long-term success. XYZ Bank’s IT staff gets trained on managing and optimizing APIs, ensuring continued efficiency in transaction processing moving forward.

Why Bother Upgrading Legacy Systems?

We’ve all heard the adage, “If it ain’t broke, don’t fix it.”

It’s not the best motto when it comes to legacy systems, although there is something to be said for the durability, familiarity, and reliability of legacy applications and technology. And that’s the beauty of legacy integration — you get to blend parts of the old with the new.

So, why bother with legacy system integration? Here are some of the benefits:

Streamlined Workflows

Integration enhances your old technology to streamline workflows and business processes. For example, data that was siloed in an old system can be integrated across departments with a new one, allowing teams to share information in real time. And rather than replacing a legacy system with entirely new systems, legacy system modernization lets you maintain the backbone of your business operations, keeping your company agile by making core systems more effective and efficient.

Access to New Functionality

Your legacy system can do a lot. But a more modern system can do more. You’ll be able to take advantage of the modern tech to explore new markets, create new revenue streams, create new opportunities for end users, improve customer service ... the possibilities are endless.

Scalability

Legacy software may not be designed to scale up when your business grows, when you enter into a new market, or you have a growing customer base. Newer systems, on the other hand, are built with this kind of scalable functionality in mind. When your company grows, your tech grows with it.

Lower Maintenance Costs

Legacy systems can be expensive to maintain, as they often require continuous maintenance from IT professionals to avoid crashes. Plus, there could be a serious financial impact on your business. With new technologies integrated with your existing systems, these worries and costs are mitigated.

Top Strategies for Legacy System Integration

There’s more than one way to go about a legacy system integration, all with their own advantages:

API Integration

The most common integration used today is Application Programming Interface (API) integration. An API is simply a collection of rules that define how an app should “behave” when accessing other features of the app or other data. Essentially, this kind of integration allows applications to “talk” to one another and share data.

API integration is popular because it allows your company to integrate hundreds of apps, if necessary, into a single system. APIs integrate with internal and third-party apps and seamlessly align with cloud and microservices architectures as well. Plus, this kind of data integration is scalable. It lets developers build upon existing services to scale up when your business needs demand it.

Example: Your retail company wants to enhance the user experience by integrating a third-party payment gateway into your e-commerce platform. By leveraging APIs provided by the payment service, your customers can seamlessly complete transactions using their preferred payment method, all within the familiar interface of your company website.

Anti-Corruption Layer

An anti-corruption layer serves as a strategic design pattern during legacy system integration. Think of it as a shield between your modern systems and your legacy systems. The anti-corruption layer ensures that the modernized components interact smoothly with the legacy systems, without being affected by the legacy system’s constraints or idiosyncrasies.

Your company might use the anti-corruption layer approach when dealing with a legacy system that uses outdated data formats or complex rules. By isolating and translating these complexities, the anti-corruption layer lets the new system communicate via a standardized interface, simplifying development and maintenance.

Example: Your manufacturing company uses an anti-corruption layer to integrate a new customer relationship management (CRM) system with existing legacy enterprise resource planning (ERP) software. The CRM system needs access to customer data stored in the ERP, which uses its own data format and business rules for orders and inventory. The anti-corruption layer standardizes data exchanges between the two systems, ensuring seamless synchronization of sales, customer interactions, and inventory updates — without affecting the ERP’s integrity. 

ESB Integration

Enterprise Service Bus (ESB) is a middleware software architecture that integrates multiple applications into a single ecosystem. ESBs are designed to work with internal systems, rather than third-party apps, and most ESBs run on-premises and usually aren’t well-suited for microservices environments. For these reasons, the ESB approach may not be the right choice if your company is working with modern applications.

Example: As a global logistics company operating a complex network of warehouses, transportation hubs, and supply chain management systems, your company implements an ESB framework to orchestrate integration across various operational systems. The integration connects your company’s order management platform, the supplier relationship management system, and the warehouse management platform into one seamless logistics ecosystem.

iPaaS Integration

Integration Platform as a Service (iPaaS), a type of Software as a Service (SaaS), is a cloud-based integration platform engineered to streamline the development, execution, and management of integrations between disparate systems. Using an arsenal of pre-configured adaptors, connectors, APIs, and ESBs, iPaaS facilitates seamless data exchange and workflow orchestration across the organizational spectrum. This method is particularly popular because it is fast, smooth, and versatile.

Example: Your company, a rapidly growing tech startup, adopts an iPaaS solution to streamline its expanding ecosystem of cloud-based applications and services. Now, when a new lead is captured in your CRM system, a personalized marketing campaign is automatically triggered from the marketing automation platform and billing records are updated in real time.

Does Your Legacy System Need an Upgrade?

You don’t have to discard it entirely and start from scratch. Legacy system integration allows you to maintain the dependability and core processes of your legacy system while capitalizing on the power of modern application, driving meaningful change within your organization.

Your legacy system may be ripe for integration, and Focused Labs is here to help your company navigate the complexities of legacy integration and digital transformation while maximizing the value of your technological investments.

And we prioritize incremental modernization to ensure your team isn’t reliant on our experts after the contract ends.

Want to learn more about our services? Ready to get started on a legacy integration project? Contact Focused Labs today.