Building a Digital Wallet & Payment App for the Nigerian Underbanked

Over 60% of Nigeria's adult population remains underbanked, lacking access to traditional financial services. A Lagos-based fintech startup wanted to change that with a digital wallet that worked for everyone—smartphone users and feature phone users alike. They needed a platform that combined mobile app convenience with USSD accessibility, supported by an agent network for cash-in/cash-out in local communities.

We built the entire platform from scratch in 4 months: a React Native mobile app, a USSD interface, an agent management dashboard, and the backend infrastructure to handle millions of transactions. Within the first quarter, the platform onboarded 50,000 users and processed over ₦200 million in transaction volume.

The Challenge

Building for Two Different User Profiles

The startup's target market included both urban smartphone users and rural users with basic feature phones. Building a single platform that served both segments required two separate interfaces—a mobile app for Android and iOS, and a USSD channel for feature phones—both connected to the same backend. The USSD integration needed to support balance checks, transfers, airtime purchase, and bill payments through simple menu codes.

On top of this, the platform needed an agent network layer that allowed local merchants to handle cash-in and cash-out transactions for users who could not fund their wallets digitally. Each agent needed a dedicated dashboard for tracking commissions, transaction history, and float balances.

Regulatory Compliance and Security Requirements

Handling financial transactions in Nigeria requires compliance with CBN guidelines for mobile money operators, including BVN-based KYC verification, transaction limits, and daily balance caps. We had to build a KYC system that could verify users through BVN lookup, NIN verification, and document upload—all within a smooth onboarding flow that did not drop off users.

Our Solution

A Unified Backend with Multiple Frontends

We built the core platform on Node.js with PostgreSQL, deploying on AWS with auto-scaling from day one. The API layer served three separate frontends: the React Native mobile app, the USSD gateway, and the agent web dashboard. This architecture meant every transaction was processed through the same business logic engine, regardless of how the user accessed the platform.

For the USSD integration, we partnered with a USSD aggregator to provision short codes. Users on any phone could dial a short code to check balances, send money, buy airtime, or pay bills. The USSD session handled authentication through their phone number and a 4-digit PIN, making it accessible even on the most basic devices.

Agent Network and Liquidity Management

We built a complete agent management system that allowed the startup to onboard merchants as cash-in/cash-out points. Agents received a web dashboard showing their float balance, transaction history, commission earnings, and customer activity. The system included automated float top-up requests and reconciliation reports that made it easy for agents to manage their liquidity without constant manual oversight.

The Results

The platform launched on schedule and hit 10,000 users in the first two weeks through a combination of agent-driven onboarding and referral campaigns. By the end of the first quarter, 50,000 users had registered, and the platform was processing ₦200M in monthly transaction volume. The retention rate remained above 92%, driven by the convenience of USSD access for users who could not always rely on smartphone data.

The agent network grew to 200 active agents across Lagos and Ogun states, handling 40% of all cash-in transactions. The startup successfully raised a Series A round 6 months after launch, citing the platform's user growth and transaction volume as key proof points.

Key Takeaways

• Multi-channel is essential for the Nigerian market. A mobile-only app would have excluded 40% of the user base. USSD made the platform accessible to everyone.
• Agent networks drive trust and adoption. Having real people in local communities who could help users fund their wallets accelerated adoption significantly.
• KYC flow optimization matters. We reduced the onboarding drop-off from 60% to 18% by simplifying the BVN verification process and allowing partial registration.
• Build for scale from day one. The decision to use AWS auto-scaling and a well-architected database schema meant the platform handled rapid growth without re-engineering.

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