A Custom-Made Architecture for the Digital Transformation of Bank Sales

Banks need to expand their digital presence if they want to stay ahead of the competition—but merely digitizing the interface to the customer is not enough. How a major European bank is driving online sales with a new omnichannel architecture on the backend.

But this project poses a major challenge: the existing backend is outdated and has serious stability issues. The only viable solution is to develop an entirely new, customized omnichannel backend that routes data from core systems to both electronic devices and traditional touchpoints like branches and vice versa. The new app will rely on this backend as a data source.



A team of experts from BCG Platinion assisted the client in developing the architecture, thus laying the groundwork to replace the unstable and poorly performing backend system with a new, state of the art omnichannel backend.

The Challenge

The COVID-19 pandemic has significantly accelerated the trend toward digitization. More and more people want to do their banking online. In doing so, they expect the same high standards from their banks in terms of availability and usability that they have come to expect from major IT players such as Amazon.



Faced with this new reality, our client, a major European bank, launched an extensive digital sales program with an ambitious goal: to double the number of digital customers. To achieve this, the bank plans to introduce an entirely new mobile app across the group.

The Approach

First, our team precisely defined the client’s requirements and created a detailed project roadmap, including the human and financial resources needed, and prioritized the key actions. Since there was no documentation of the existing backend, the required capabilities of the backend were gathered, and extended or changed if needed.



To lay the foundation for a modern, future-proof omnichannel backend, it was necessary to develop a completely new, one hundred percent greenfield architecture. We validated the feasibility of this future architecture in a proof-of-concept (PoC).

The new backend can seamlessly be migrated to the cloud if required and introduces new technologies and concepts not used before into the customer’s IT. Examples include the following:

  • 1.

    Event Driven Architecture

  • 2.

    Micro Service Architecture

  • 3.

    API Driven Integration

  • 4.

    Domain Driven Design

  • 5.

    Near real-time Data Caches for core systems (in fact real-time for business)

  • 6.

    Full Continuous Integration/Delivery capabilities

    The Impact

    The new omnichannel capabilities significantly improve customer experience, making the use of the bank’s digital offerings more attractive and enabling it to achieve its ambitious sales targets—a doubling of digital customers.



    With the new system, it is easier and more cost-effective to provide new functions for bank customers frequently. The maintenance effort will also be lower. We have reduced the backend complexity and code redundancy.



    The newly developed architecture makes the IT department’s job easier and helps improve collaboration between the business and IT teams. It enables agile ways of working through domain-oriented design and the microservices architecture minimizing dependencies between business departments. This approach allows teams to reduce delivery time of new features going into production.

    Looking at the Future

    As a result of our work, the major European bank now has an effective, modern, and customer-focused backend. For this, we developed a state-of-the-art architecture and validated it end-to-end on a live system.



    The strategy we developed includes a concept for the parallel coexistence of the old and the new backend, a migration plan for transferring data from these systems, as well as an investment estimate. This includes all expected costs for the development and maintenance of the platform in terms of infrastructure, personnel, and licenses.

    The new omnichannel backend is the foundation for the bank’s digital sales initiative and a key enabler to significantly increase customer experience and thus customer satisfaction.

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