From Legacy Systems to API Economies: The Future of Open Core Banking
How Indonesia’s Banks Are Transitioning to Composable and API-Driven Banking Models
Indonesia’s banking sector is at a decisive point as institutions shift from monolithic core systems towards flexible, API-driven architectures. With rising transaction volumes, growing fintech participation, and strong regulatory direction, banks are rethinking how core systems are designed and deployed.
For decision-makers evaluating long-term technology investments, the conversation is no longer about incremental upgrades — it is about building adaptable foundations that support collaboration, scalability, and new revenue models. This transition is becoming a central theme across every major banking technology conference, reflecting its strategic importance across Southeast Asia.
The Limitations of Legacy Core Banking Systems
Legacy core banking systems in Indonesia, often running on-premises, mainframe-based infrastructure, act as significant barriers to transformation, innovation, and customer experience, with 90–95% of banks in the ASEAN region still relying on these aging systems.
In Indonesia, these constraints are further intensified by geographic complexity and a shortage of professionals skilled in both legacy and modern platforms.
Key Limitations Include
High Operational & Technical Debt
A large portion of IT budgets (60–80%) is spent maintaining outdated infrastructure
Monolithic systems struggle to scale alongside rising digital transaction volumes
Talent shortages in legacy programming ecosystems heighten operational risk
Rigid Architecture & Lack of Agility
New financial products roll out slowly compared to fintech competitors
Siloed data prevents a unified view of the customer
Transformation Barriers
Limited compatibility with API-based integrations
Difficulty supporting Banking-as-a-Service models
A disconnect between modern front-end applications and outdated back-end systems
Risk and Compliance Pressures
Growing exposure to cybersecurity threats
Difficulty adapting to evolving regulatory requirements set by OJK
Complex Modernization Efforts
High-risk, multi-year system replacement projects
Frequent delays caused by hidden system dependencies
Understanding API Economies in Financial Services
Indonesia’s financial ecosystem is increasingly shaped by API-led collaboration, driven by initiatives such as the Standard National Open API Payment (SNAP). These frameworks standardize how banks and fintechs interact, enabling faster service development and broader financial access.
Key Components Include
Regulatory Framework (SNAP): Standardizes API integration across institutions
BI-FAST Integration: Enables real-time, low-cost transactions through API connectivity
Growth Segments: Digital banking, P2P lending, and e-wallet platforms
Financial Inclusion: Expands access to credit for MSMEs through improved data sharing
This shift is redefining how institutions position themselves within the broader banking solutions ecosystem, where collaboration is becoming as important as competition.
Composable Core Banking: A Modular Approach to Innovation
Composable core banking introduces a modular structure where individual services operate independently and interact through APIs. Instead of replacing entire systems, banks can upgrade or deploy specific components as needed.
Core Characteristics
Modular Structure: Independent building blocks for different banking functions
API-First Design: Ensures interoperability across internal and external systems
Microservices Architecture: Enables flexibility and faster deployment cycles
Cloud-Native Foundations: Supports scalability and resilience
Benefits for Financial Institutions
Faster product launches and reduced development timelines
Ability to integrate fintech capabilities without major system setbacks
Lower operational risks through phased modernization
More personalized financial services through targeted service combinations
Cloud & Infrastructure Modernization in Indonesia
Indonesia’s banking sector is rapidly modernizing its infrastructure to support a growing digital economy, with over 180 million smartphone users and an expanding base of digital banks. This transformation is closely linked to the adoption of cloud banking in Indonesia.
Key Trends Include
Migration to hybrid and multi-cloud environments
Growth of digital-only banks such as Bank Jago and SeaBank
Regulatory support encouraging secure cloud adoption
Increased use of containerization and serverless technologies
Modernization Initiatives
Deployment of cloud-native platforms for real-time services
Strategic partnerships with global technology providers
Adoption of AI and data analytics for decision-making and fraud detection
Challenges
Uneven digital infrastructure across regions
Shortage of skilled cloud and cybersecurity professionals
Data sovereignty and compliance requirements
Managing Risk, Security, and Governance in Open Architectures
As banks adopt API-driven and modular systems, managing risk becomes increasingly complex. Open architectures require strong governance frameworks to maintain control while enabling collaboration.
Ensuring compliance with evolving regulatory standards
Establishing clear data governance and access controls
Defining clear leadership accountability for technology risk
Openness and control are not opposing forces, getting that balance right is what sustains trust while enabling innovation.
Business Impact: Speed, Efficiency, and New Revenue Models
The transition to composable and API-based banking models delivers measurable business outcomes beyond technology improvements.
Key Impacts
Faster time-to-market for new products and services
Reduced operational costs through automation and system flexibility
New revenue streams through embedded finance and partnerships
Improved customer experience through integrated service delivery
Alignment between technology investments and business strategy
For executives, the question is therefore not whether to pursue these outcomes, but how quickly and coherently they can be executed across the organization.
Industry Collaboration and Technology Dialogues
Modernization rarely happens in isolation. Collaboration across banks, fintechs, and technology providers is what turns strategy into successful execution — and industry forums are where that collaboration takes shape.
Participation in a leading banking technology event enables stakeholders to:
Exchange real-world implementation experiences, not just frameworks
Identify partnership opportunities within an increasingly interconnected ecosystem
Evaluate emerging technologies against the realities of regulated environments
Align modernization strategies with evolving regulatory expectations
Equip leadership with the perspective needed to make informed, high-stakes decisions
Gain Insights into Modern Core Banking Models at WFIS!
The infrastructure decisions Indonesian banks are making now — on core modernization, API adoption, cloud migration, and governance — will define how they compete for the next decade.
For the leaders navigating these decisions, the World Financial Innovation Series returns to Jakarta as the region’s most focused forum for exactly this work.
Agenda Highlights
‘Transforming Core Banking into an Open, Composable Platform for the API Economy’
‘Cloud as Critical Infrastructure: Re-Architecting Financial Services for Scale, Speed & Supervisory Confidence’
‘Steering Indonesia’s Financial Sector 2030: Stability, Supervision & Digital Acceleration Under New Regulatory Mandates’
Attendee Profile
C-suite and senior executives from Indonesia’s leading banks, insurance companies, and microfinance institutions
Chief Information, Technology, and Digital Officers driving core modernization and cloud adoption
Chief Risk, Compliance, and Legal Officers managing OJK regulatory requirements and governance frameworks
Fintech leaders and innovators building within Indonesia’s regulated financial ecosystem
Event Details
Date: 27–28 October 2026 Venue: Raffles Jakarta, Indonesia
Don’t miss out on one of Southeast Asia’s most substantive gatherings for financial services leaders navigating the next phase of institutional transformation.