Greenfield core: de-risking a coreless, multi-vendor build for an institutional bank
FINANCIAL SERVICES · TECHNOLOGY · ARCHITECTURE AND DELIVERY
The situation
A major institutional bank had lost about a quarter of its transaction-banking revenue and was shedding corporate clients, held back by a rigid legacy core. Earlier attempts to build modern features over the old system had failed and driven up cost. The bank chose to build a new cloud-native engine from the ground up. That introduced its own risks: a buy-rather-than-build approach stacked several independent providers, an account host, a payments engine, and liquidity tools, with fragmented integration; corporate clients on bespoke legacy workflows would need to run in parallel for up to three years without disrupting treasury; and the internal team lacked the cross-functional, cross-vendor delivery practices the new model required.
The work
We designed a delivery model to align the multi-vendor stack with clear corporate-client journeys.
Set up a single design authority on day one to hold the technical blueprint across all providers and keep the backlog two cycles ahead.
Replaced separate teams with autonomous, co-located journey labs of engineering, business, design, and operations.
Built a steel thread, a thin end-to-end slice, rather than a linear eighteen-month launch, testing live integration every sprint.
Engineered a lean gateway on a modular API mesh so engines spoke to each other directly, avoiding single-vendor lock-in, and aligned partner commercial models to single points of accountability.
Rejected big-bang migration for a domain-driven, streaming move that shifted clients in waves by service tier and readiness.
The outcome
A greenfield build aimed at reclaiming the lost revenue pool without legacy constraints.
A delivery model shifted from a rigid linear launch to continuous, verifiable value.
Multi-vendor governance that kept orchestration clean and avoided lock-in.