How to Move a Bank’s Heart Without Breaking It

By Tosin Clegg

An expert in banking technology and large-scale core platform migrations, Emmanuel Ezekiel has revealed the meticulous engineering principles that ensure smooth transitions when banks switch their digital backbones. Drawing from his experience in multi-market Finacle deployments across Africa, Ezekiel says the golden rule remains simple yet sacred: never cut over without a way back.

According to him, every successful migration begins with a solid rollback plan. It is the project’s insurance policy—designed early, tested repeatedly, and simple enough to trigger when pressure mounts. Go-live gates, he explains, are non-negotiable: a full dress rehearsal using production-like data, reconciliation thresholds agreed with finance, and live paging drills. If any of these fail, timelines shift. “It’s better to disappoint a plan than to disappoint a million customers,” he insists.

Legacy systems, Ezekiel notes, often hide decades of business rules inside batch jobs. His teams start by cataloguing every job, retiring dead logic with business approval, and rebuilding the rest under named ownership. Golden-record mapping and contract tests are completed before any data moves. “We don’t proceed until reconciliations clear hard thresholds,” he adds.

For Ezekiel, the smartest deployments always run old and new systems in parallel before the final switch. A single toggle can redirect traffic back to the legacy stack if issues arise. “That safety belt changes behaviour,” he says. “People raise issues earlier because failure is no longer a cliff.”

He stresses that true governance begins with visibility. Every end-to-end journey—from login to statement—is continuously instrumented. Synthetic probes watch key processes, and logs double as audit evidence, giving executives and regulators the same view engineers have during cutover.

Ezekiel believes collaboration is the invisible glue. Banks, vendors, and delivery partners share one incident channel, one change board, and the same pager duty. “Identical metrics and shared accountability reduce hand-offs and eliminate blame loops,” he says. “The triangle only works when it behaves like one team.”

From the customer’s perspective, the best migration is one they never notice. ATMs work. Cards swipe. Salaries post. “The real dividend,” Ezekiel concludes, “arrives later—when stable APIs empower product teams to ship faster, safer, and smarter.”