Migrating a 30-year-old system to Azure cloud in phases stabilized operations and prepared microservices architecture for enterprise-wide digital transformation.

Client challenge: An energy company’s internal-billing system required complex tech integrations that could not support its broader digital transformation strategy.
 
Solution: The finance system was migrated from the mainframe to Azure cloud in phases and prepared for microservices architecture.

Business outcomes:
• Processes thousands of transactions each month
• Positions the company for growth
• Maintains continuity without any downtime for the financial system
• Scales efficient financial processes and tools throughout the global organization smoothly
• Provides employees with a better user experience

Imagine trying to transform a business that still relies on a billing system that’s been in place for 30 years. A top provider of energy equipment and services found itself in just this position in the late 2010s. The company’s leadership understood that an outdated finance system, which touches every part of the organization, would impede broad digital transformation. Something had to be done.

The global energy company asked longtime partner Capgemini for assistance modernizing this finance system so it could propel rather than impede the pace of transformation.

Capgemini knew that migrating the existing internal billing system to the cloud would give the organization access to the latest capabilities and developments. At the same time, the company needed a thoughtful, deliberate strategy that would not disrupt daily operations. Here’s how they did it.

From legacy to cloud: Understanding the scope of the challenge

The existing finance system included several issues common to legacy technologies. It required ongoing upkeep to operate effectively alongside new platforms, which took up time and energy that could’ve been better spent on other activities.

The client wanted to build a brand-new system on Microsoft Azure, one of the world’s leading cloud-computing platforms, offering a range of services that help businesses build and deploy applications.

However, modernizing the system was no easy task. Migrating existing tools and processes to cloud presented both technical and change-management challenges. Engineers had to integrate more than 250 enterprise resource planning (ERP) systems, which help manage core business processes, and more than 1,600 billing unit codes across 108 countries. These all needed to work alongside the middleware, which bridges operating systems and applications.

Microservices: a transformative solution

Capgemini developed a phased, strategic approach to modernizing the billing system. Starting in 2020, the team prepared different components for microservices, a software development approach that makes it easier to develop and scale applications.

Monolithic software architectures link all processes, so they run as a single service. But microservice architectures decouple different processes into small independent services for greater agility and modularity.

The different microservices can still communicate with each other over defined application programming interfaces (APIs), but companies enjoy greater technological freedom. If one aspect of the system is malfunctioning or lagging, engineers can easily replace it without disrupting the rest. This flexibility empowers teams to update the system as technology accelerates, so it’s always running on the most advanced software.

Tapping into Capgemini’s experience and expertise with microservices ensured that each element of the finance system was ready for the newly built Azure environment.

Wave-based integrations

The implementation team integrated the many ERP platforms and middleware components into the new cloud system in waves. Avoiding a single large-scale rollout allowed them to account for the specific configurations and requirements of each.

Overall, the team integrated more than 150 previous components into the new cloud environment. But these components had been built into the legacy system using different platforms, which were incompatible with each other – posing a challenge.

We leveraged our expertise in multiple middleware-integration services to move more than 150 separate components to the new solution. Turning this obstacle into an opportunity, the engineers capitalized on the specific strengths of each integration service. For instance, Boomi was ideal for hybrid integrations, whereas Informatica was perfect for data integration.

Testing and quality assurance

The team decided to perform both system integration tests (SIT) and user acceptance tests (UAT), which ensure the technical components work as expected and that the user’s needs are met, respectively.

Using computer-aided translation (CAT) software the team conducted more than 1,500 functional test cases to check that the system operated as intended and more than 175 interface test cases to validate that information was being shared between the different platforms.

Concurrently, the team performed narrower “sanity checks” to make sure specific functionalities worked properly after updates and changes. These were specifically carried out for integrations related to high-priority energy clients.

Compliance and security

Microsoft Azure environments are generally more secure than traditional on-premises servers, thanks to Microsoft’s security controls and regular updates. However, the ultimate protection level depends on the configuration and management of each platform.

Network administrators and compliance specialists needed to navigate stringent security protocols, set up firewall rules for handling the flow of network traffic, manage port configurations, and ensure secure authentication methods.

The team adhered to secure file transfer protocol (SFTP), which protects sensitive information whenever employees send or receive files. This set of rules calls for encrypting data transmitted between two devices on the same network. Known as secure-shell encryption, this cryptographic method prevents unauthorized users from accessing protected data by assigning each device a public key (generated by an algorithm) that corresponds with a private key.

Business outcomes

The collaboration led to the successful modernization and migration of the internal-billing system. Post go-live in July 2024, Capgemini didn’t just deliver the application but also delivered critical inaugural activities:

  • Processing thousands of transactions
  • Completing three settlement cycles (reconciling charges between departments), which occur twice a month
  • Executed month-end routines, such as allocating expenses and generating invoices
  • Closed financial quarters through more rigorous processes (e.g., regulatory checks, rate adjustments).

Now, the systems and processes are in place for these activities to continue. Thanks to a trouble-free deployment, the business enjoys the following benefits:  

  • Maintaining continuity without any downtime for the financial system
  • Scaling efficient financial processes and tools throughout the global organization smoothly
  • Providing employees with a better user experience
  • Avoiding follow-up requests from regulatory bodies through clear reporting
  • Positioning the company for future growth, powered by greater financial visibility.