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Case study · A leading bank with over 1.5 million users

Seamless migration from legacy systems to modern digital banking

Large-scale migration from a legacy internet banking system to a modern microservices-based architecture, with stronger scalability, security and user experience, while keeping customer trust intact.

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Client
A leading bank with over 1.5 million users
Industry
Banking, FinTech
Tech stack
Kotlin, Swift
Timeline
6 months
OutcomeWhat the work delivered
1.5M+
users migrated
6 months
to delivery
Legacy to digital
without disruption
The challengeThe brief, and what was at stake

A leading bank with over 1.5 million users was held back by its legacy system, which made flexible updates and interface redesigns hard. It needed modern, agile infrastructure without disrupting the customer experience.

Our approach

  • A parallel migration strategy, rolling out new features gradually.
  • AI-driven chatbots to bridge the gap between the legacy and modern systems.
  • An API-first approach for clean interoperability between old and new banking services.
  • Real-time monitoring and rollback to prevent service disruptions.

Final results: what did we deliver?

  • A fully scalable, microservices-based banking system.
  • A smooth transition, with minimal customer complaints and better UX ratings.
  • Less system downtime and better operational efficiency.
  • AI-powered customer support for a smooth transition.

Outcome: a step-by-step, risk-managed move from legacy to modern banking, keeping the business running and ready to scale.

Legacy to digitalA legacy core holding your roadmap back?

We migrate millions of users to modern digital banking without disruption - and own the cutover.

Scope your migration
How we built itWhat WislaCode designed and shipped
01Defining the core system architecture

Legacy banking systems often struggle with outdated architectures that lack modularity. Our strategy focused on:

  • Progressive feature migration to a cloud-native microservices platform.
  • Ensuring compliance with banking regulations while modernising data storage and processing.
  • Enhancing security with AI-driven fraud detection and risk management solutions.
Defining the Core System Architecture
02Key technological solutions
  • Microservices architecture transforms monolithic systems into modular, independent services that offer greater flexibility.
  • AI-driven chatbots facilitate seamless user interactions across both legacy and modern platforms.
  • Real-time data synchronisation ensures secure customer and transaction data migration without downtime.
  • An API gateway and orchestration system efficiently manages existing and new infrastructure integration.
  • Automated testing and rollback mechanisms help prevent disruptions during a phased migration process.
  • AI-powered fraud detection enhances security both during and after the migration.
Key technological solutions
03Full migration & optimisation

We developed a structured and cost-effective migration plan. It began with an in-depth assessment and architectural design, followed by developing and integrating core banking APIs.

Next, we progressively rolled out new features while continuously monitoring performance. The final phase included full migration, optimisation, and security enhancements, resulting in a more agile system, reduced operational costs, and improved digital banking performance.

Full Migration & Optimisation
Related servicesThe capabilities behind this outcome
Legacy system modernisation

WislaCode offers comprehensive legacy system modernisation services, transforming outdated software into modern, efficient applications. Our application modernisation solutions enhance performance, scalability, and security, ensuring your business stays competitive as you scale.

See the service Mobile app development

Native, cross-platform and super app builds, with SDKs and push infrastructure.

See the service Mobile banking app development

Mobile banking apps for regulated banks: native, PWA and hybrid, integrated with your core, identity and payment rails.

See the service Payment solutions development

Payment solutions across the transaction flow - acceptance at POS, online and in wallets, PSP and acquirer integration, PCI DSS, settlement and reconciliation.

See the service
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