9jaPay — Business banking, shipped in five weeks

The brief

9jaPay's product team had a hard constraint: the business banking MVP had to be in customers' hands within five weeks. The platform needed to handle the full lifecycle — onboarding, business verification, account creation, transfers, and a credible-looking ledger — without cutting corners on the things banking customers actually notice.

I came in to lead the frontend architecture and ship the product end-to-end alongside a backend team and a designer.

Approach

• Typed contracts first. I started by codifying the GraphQL schema as TypeScript types and building a thin React Query layer on top. Components consumed typed data — never raw responses — which made the testing story much simpler.
• A small, opinionated component system. Buttons, inputs, money displays, KYC step indicators, transaction rows. Twenty primitives, composed everywhere, accessible from the first commit.
• A real onboarding flow. Multi-step KYC/KYB with optimistic state, recoverable errors, and a saved-progress contract so users could pick up where they left off.
• Observability from day one. Sentry was wired in before the first deploy, with custom breadcrumbs around financial operations. Production incidents were diagnosable in minutes, not days.

Outcome

• Shipped in 5 weeks without sacrificing the testing and observability story.
• Cut incident resolution time by giving every error a Sentry breadcrumb trail.
• Held the regression rate flat across three subsequent releases — the type system and component contracts caught issues before they shipped.