Core Modernization Playbook: How Banks Can Successfully Transition to Modern, Cloud-Based Core Systems

Modernizing the core banking system is one of the most critical—and daunting—challenges facing banks today. Legacy technology stacks are increasingly unable to keep pace with the demands of digital-first customers, regulatory change, and the need for operational agility. Yet, the risks, costs, and complexity of core transformation have historically made it a high-stakes endeavor. The good news: new technologies, proven methodologies, and a progressive, iterative approach are making successful core modernization not only possible, but essential for banks that want to lead in the digital era.

This playbook provides a step-by-step guide for banks considering or undertaking core modernization, drawing on Publicis Sapient’s deep experience in delivering complex transformation programs for leading financial institutions worldwide. We outline the four key phases of a successful journey—confirming ambitions, mobilizing the program, proving the platform, and scaling progressively—while highlighting common pitfalls, risk mitigation strategies, and the transformative benefits of a coreless architecture.

The Core Banking Conundrum

Bank leaders overwhelmingly agree on two points: their current core systems are struggling to support the seamless, digital experiences customers expect, and replacing these systems is risky, complex, and expensive. Yet, the shift to modern, cloud-based core technologies is inevitable. Every year, banks spend more just to maintain the status quo, while workarounds and patchwork integrations make further change riskier and more costly. New regulations, rising digital expectations, and open banking are pushing legacy systems to the limit.

Key statistics:

The Case for Core Modernization

Modernizing the core is no longer just a technology upgrade—it’s a strategic imperative. Banks that succeed unlock:

A Four-Phase Approach to Core Modernization

Publicis Sapient’s proven methodology breaks the journey into four clear, actionable phases. At each step, we identify the critical jobs to be done, common pitfalls, and strategies for risk mitigation.

1. Confirm Your Ambitions

A successful program starts with a clear, aligned ambition—one that is understood and committed to by the board, leadership, and delivery teams. Failure often stems from an unclear case for change or lack of leadership buy-in.

Key actions: Pitfalls to avoid:

2. Mobilize the Program

With ambitions set, the next step is to set up the program for success—ensuring the right people, roadmap, and vision are in place.

Key actions: Pitfalls to avoid:

3. Prove the Platform

The program must deliver real, customer-facing value early. A ‘pathfinder’ launch—targeting a specific product, segment, or journey—proves the new platform’s capabilities and builds organizational belief.

Key actions: Pitfalls to avoid:

4. Scale, Progressively

With the platform proven, accelerate expansion and migration through iterative releases. Manage the coexistence of old and new systems, and sustain momentum with strong communication and change management.

Key actions: Pitfalls to avoid:

Risk Mitigation Strategies

The Power of Coreless Architecture

A coreless, cloud-based architecture decouples data and business logic from monolithic systems, enabling banks to:

The Link to Agility, Customer Experience, and Innovation

Core modernization is not just a technology upgrade—it is the foundation for:

Why Publicis Sapient?

With a track record of delivering successful core modernization programs for leading banks worldwide, Publicis Sapient brings:

Ready to Modernize Your Core?

The journey to a modern, cloud-based core is complex, but with the right approach and partner, it is achievable—and essential. Banks that act now will unlock new efficiencies, deliver superior customer experiences, and position themselves for sustained growth and innovation in the digital era.

Let’s start your core modernization journey—together.