Finance & FinTech
Our client is a regional commercial bank serving over 400,000 retail and SME customers across Southeast Asia. Founded over six decades ago, the bank had built a strong regional reputation but its core banking platform was a heavily customised mainframe system implemented in the early 1990s, maintained by a shrinking pool of specialists familiar with its codebase.
The system worked, in the sense that it processed transactions reliably. But it could not support the products customers now expected: real-time payments, instant digital account opening, or integration with modern payment networks. Every new feature request took months and carried significant risk of disrupting core operations.
The bank had previously attempted a full platform replacement with a different vendor a project that was abandoned after 18 months and significant cost overruns, having never reached production. When they approached DashMindsIQ, the primary requirement was clear: this needed to work, on a realistic timeline, without repeating that experience.
The bank's branches and ATM network needed to remain fully operational throughout the migration. Any extended outage would directly affect customer trust and regulatory standing.
Every change to core ledger systems required a documented audit trail acceptable to the Monetary Authority's examination process no "move fast" shortcuts were viable.
After the previous vendor's failed attempt, internal stakeholders were skeptical of any "full replacement" framing. The approach had to demonstrate value incrementally.
Rather than proposing a "big bang" replacement, we recommended a strangler-fig migration: build a modern core banking layer alongside the existing mainframe, progressively route transaction types to the new system, and decommission mainframe components only once their replacements had proven stable under full production load.
We spent the first two months mapping every transaction type processed by the mainframe, working alongside the bank's existing operations team to document business logic that had never been formally specified much of it existed only as undocumented behaviour in 30-year-old code.
We built a new core ledger system on AWS, using event sourcing to maintain a complete audit trail of every account transaction satisfying regulatory requirements while enabling real-time processing. This ran in parallel with the mainframe, processing shadow transactions for validation without affecting live operations.
Starting with the lowest-risk product (savings accounts), we progressively cut over transaction types to the new core, each phase running for 4–6 weeks in shadow mode before going live, with instant rollback capability maintained throughout.
With all transaction types running on the new core, we connected the bank's mobile app and online banking platform via new APIs, enabling instant account opening and real-time payments for the first time and decommissioned the remaining mainframe components.
"DashMindsIQ delivered our core banking modernisation programme on time and within budget something our previous vendors had repeatedly failed to achieve. Their domain knowledge of financial systems was immediately apparent, and the phased approach meant our branches never felt a thing."