FinTech E-Wallet and Digital Payments Platform Development for PayQin
FinanceA case study of an international FinTech platform: e-wallet, virtual cards, multi-currency transfers, QR payments, and a business API. Built with a MERN architecture and React Native mobile apps.
About the Project
Finance / FinTech • iOS, Android, Web • Payment Platform
PayQin is a FinTech startup delivering digital financial services for users across African markets. The platform combines an e-wallet, virtual Visa/Mastercard cards, and an online payment gateway, allowing users to send money and make purchases across countries and currencies.
The project addresses a major challenge in emerging markets: the lack of unified financial infrastructure and the complexity of cross-border payments.
Objective
Build the PayQin MVP from scratch, including mobile and web applications, based on a ready-made design provided by the client.
Platform functionality:
- Management of e-wallets and virtual cards
- Money transfers between countries and currencies
- Online purchases and digital payments
- Invoice workflows: creation, receipt, payment, and cancellation
- API integration for websites and online stores
- QR code payments for accepting and making payments
Challenges
A universal product for different currencies and markets
PayQin was designed to support fast and reliable international transfers, including regions with limited banking infrastructure. We adapted the business logic to handle multi-currency transactions and local market constraints.
Simplicity and accessibility
UX flows were built for users with little or no prior experience with digital payments. Creating a wallet, issuing a virtual card, and starting transfers could all be done in just a few taps.
Centralized financial dashboard
We built a single financial dashboard that brings together transaction history, balances, invoices, and operational analytics. The interface followed a minimalist design approach, keeping all key information visible on one screen.
One-click invoicing
The invoicing flow was designed around a peer-to-peer model: users could send and receive invoices, define payment deadlines, cancel unpaid invoices, and get notified about payments and outstanding balances.
Security and trust
Special attention was paid to protecting financial operations: secure authentication, encrypted requests, CVV and personal data protection, HTTPS, isolated API endpoints, and token-based transaction control.
Support for small businesses
The platform included API and SDK options for integrating PayQin into online stores and digital services, as well as support for offline payments via QR codes.
How We Built It
Technology architecture
The project was built on the MERN stack (MongoDB, Express, React, Node.js): Node.js + Express for the backend API, authorization, and transaction logic, React for the web-based e-wallet interface, React Native + Redux for a shared iOS and Android mobile codebase, and MongoDB for storing user, wallet, and transaction data. A unified JavaScript stack allowed the team to work in parallel across all parts of the product and deliver the MVP in 5 months.
Implementation of the client’s design
We worked from design assets provided by the client and adapted them for a financial product. All interface components were implemented according to the supplied layouts, ensuring a consistent user experience across web and mobile platforms.
Delivery stages
The project was delivered in several stages: product analysis and architecture design, backend API and integration development, front-end implementation for web and mobile, testing and CI/CD setup, followed by a pilot launch in West African markets.
Testing and DevOps
The QA team covered the full testing cycle: functional, integration, and load testing, as well as API and payment security checks. Automated CI/CD pipelines supported fast iteration and reliable releases.
Results
MVP developed and launched
In 5 months (2018)
Applications released
iOS, Android, and web
Core functionality fully delivered
Digital wallet and invoicing
Product support and growth
2018–2020
Technology Stack
Frontend (Web)
Frontend (Mobile)
Backend
Database
Integrations
DevOps
Download the App
The PayQin platform is available in the official app stores:
Outcome
We delivered a turnkey PayQin MVP platform — a web and mobile service for secure online payments and cross-border transfers across African markets. In 5 months, we brought the product to market, then supported and evolved it for two years, before handing over the codebase and infrastructure to the client’s internal team for further scaling.
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