.png){kind=logo}
How a Leading PSB Shifted from Legacy CBS to Microservice Integrations
Indian Bank, one of India’s largest public sector banks, serves millions of customers through branches, ATMs, and digital channels. Its core banking system (CBS) drives account management, payments, and lending operations. With rising digital adoption and initiatives like UPI and Aadhaar services, seamless CBS integration with internal and external applications became critical. Legacy tools were slow, hard to maintain, and struggled with high-volume transactions. Our team implemented an ESB using App Connect Enterprise (ACE) on IBM Cloud Pak for Integration (CP4I), creating a secure, flexible, and high-performance integration backbone.
Tech used
Microservice
Zero Trust
Automation
API Management
India
Challenge
The first major challenge faced by the bank was the rigidity of its integration environment. Core Banking System (CBS) connectivity relied on a patchwork of custom scripts, point-to-point connectors, and legacy middleware. These brittle connections demanded heavy manual intervention whenever updates or changes were required. As a result, introducing new services such as mobile banking enhancements or digital loan applications often took several weeks due to lengthy integration cycles, limiting the bank’s agility in responding to customer and market demands.
Scalability and performance were also significant concerns. During peak periods, such as month-end closures or government disbursements, the existing integration layer could not keep pace with transaction surges. The absence of asynchronous processing and event-driven integration models led to transaction slowdowns and, in some cases, service outages. These disruptions negatively impacted customer experience and exposed the bank to regulatory scrutiny for failing to consistently meet service-level agreements.
The third challenge was governance and security. Sensitive financial and personal data traversed multiple systems, but the legacy setup offered little visibility or centralized monitoring. Encryption and audit logging were either inconsistent or absent, making compliance with strict regulatory requirements difficult. Without a unified view of integration flows, tracing transactions end-to-end was nearly impossible, increasing both operational risk and the likelihood of regulatory penalties.
Solution
As the implementation partner, Cateina designed a comprehensive integration strategy anchored on IBM Cloud Pak for Integration (CP4I) to establish a robust ESB layer. The solution decoupled the CBS from downstream applications while enabling faster onboarding of new services. By following a phased rollout—starting with non-critical services before expanding to mission-critical payment and compliance workloads—the approach ensured business continuity during the transition.
Our team developed services on App Connect Enterprise (ACE) within containerized runtimes, giving the bank a microservices-based ESB architecture. This allowed for the reuse of connectors and service mediation patterns, while standardized integration templates for common banking functions—such as balance inquiries, fund transfers, and loan origination—reduced development time for future integrations. The architecture was built for resilience, modularity, and long-term scalability.
Security and governance were reinforced across the integration layer. Data flows were encrypted end-to-end, and detailed audit logs were implemented for all CBS interactions, ensuring compliance with RBI guidelines. Centralized monitoring dashboards in CP4I gave the bank real-time insights into traffic, latency, and errors. Automated alerts allowed IT teams to proactively identify and resolve issues, reducing mean time to resolution. Furthermore, Cateina invested in knowledge transfer, conducting workshops and preparing documentation to empower the bank’s internal teams to independently manage, optimize, and extend the ESB.
Result
The deployment of IBM CP4I fundamentally transformed the bank’s integration environment, delivering agility, performance, and compliance. Integration timelines that once stretched to three or four weeks were reduced to just five to seven days, accelerating the rollout of new digital services. This improvement in agility helped the bank fast-track its digital transformation roadmap and respond more effectively to customer expectations.
Performance gains were equally noteworthy. The new ESB layer managed nearly double the transaction volumes during peak load periods without degradation. Critical services such as UPI and NEFT processed transactions in real time, ensuring uninterrupted customer experiences. Downtime incidents decreased by 40%, which not only restored customer trust but also strengthened the bank’s reputation in digital service delivery.
Operational efficiency was significantly enhanced with centralized governance and monitoring. The IT team could view all CBS integrations through a single dashboard, reducing mean time to resolution by almost 50%. Standardized templates lowered IT costs by reducing duplicate efforts, allowing teams to focus on innovation rather than firefighting. Most importantly, by exposing secure APIs through CP4I’s API management, the bank seamlessly onboarded fintech partners and government platforms. This positioned the institution to actively participate in India’s open banking ecosystem while ensuring compliance and long-term competitiveness.
