A growing financial institution was boxed in by a monolithic core: every new product took months. Zimozi led a phased migration to cloud-native microservices and built an API/Banking-as-a-Service layer, turning the core into a platform that powers embedded-finance partners.
The bank ran on a tightly-coupled legacy core. Releases were big, risky and infrequent; scaling meant scaling everything; and there was no clean way to expose banking capabilities to partners. Meanwhile the market was moving to embedded finance, and competitors were shipping products in weeks. A full “rip and replace” was too risky, so the bank needed a way to modernize while staying live.
Monolithic deploys meant months per product and high blast radius on every change.
Banking capabilities were locked inside the core, impossible to offer as clean, governed APIs.
Vertical scaling of the whole monolith was expensive and inefficient at peak.
Migration had to happen with zero downtime and no disruption to live customers.
We mapped the core into bounded domains (accounts, payments, cards, ledger, onboarding) and prioritised by business value and risk.
New cloud-native microservices took over capability by capability behind an API gateway, routing traffic gradually with zero-downtime cutovers and instant rollback.
An event-sourced ledger and streaming backbone gave consistency, auditability and real-time data across services.
Governed, versioned APIs (accounts, payments, KYC, cards) with sandbox, partner onboarding and usage controls, turning the core into a product partners can build on.
The legacy core was progressively replaced by independently deployable services behind a single gateway, with an external BaaS surface for partners, all without a big-bang cutover.
The BaaS layer lets approved partners embed accounts, payments and cards into their own products, with a sandbox, versioning and usage governance built in.
“We went from dreading releases to shipping products in weeks, and our core is now a platform other businesses build on, not a bottleneck.”
We help banks move off legacy cores safely and turn banking capabilities into embedded-finance products. Let’s map your path.
© 2026 Zimozi Solutions
