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Full Stack Software Engineer with hands-on experience building, maintaining, and scaling production applications across fintech, edtech, and security-focused products. I work comfortably across frontend and backend systems, and I’ve shipped features that handle real users, real money, and real production constraints. My work spans React and TypeScript frontends, backend services built with Java and Node.js, payment integrations, and SDK development. I enjoy solving practical problems—debugging production issues, improving performance, and writing code that other engineers can understand and maintain.…Full Stack Software Engineer with hands-on experience building, maintaining, and scaling production applications across fintech, edtech, and security-focused products. I work comfortably across frontend and backend systems, and I’ve shipped features that handle real users, real money, and real production constraints. My work spans React and TypeScript frontends, backend services built with Java and Node.js, payment integrations, and SDK development. I enjoy solving practical problems—debugging production issues, improving performance, and writing code that other engineers can understand and maintain.

Precious Amarachi Onyeukwu

Full Stack Developer, Web Developer, Front-End Developer, +1

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Full Stack Software Engineer with hands-on experience building, maintaining, and scaling production applications across fintech, edtech, and security-focused products. I work comfortably across frontend and backend systems, and I’ve shipped features that handle real users, real money, and real production constraints. My work spans React and TypeScript frontends, backend services built with Java and Node.js, payment integrations, and SDK development. I enjoy solving practical problems—debugging production issues, improving performance, and writing code that other engineers can understand and maintain.…Full Stack Software Engineer with hands-on experience building, maintaining, and scaling production applications across fintech, edtech, and security-focused products. I work comfortably across frontend and backend systems, and I’ve shipped features that handle real users, real money, and real production constraints. My work spans React and TypeScript frontends, backend services built with Java and Node.js, payment integrations, and SDK development. I enjoy solving practical problems—debugging production issues, improving performance, and writing code that other engineers can understand and maintain.

Available to hire

Full Stack Software Engineer with hands-on experience building, maintaining, and scaling production applications across
fintech, edtech, and security-focused products. I work comfortably across frontend and backend systems, and I’ve shipped
features that handle real users, real money, and real production constraints.
My work spans React and TypeScript frontends, backend services built with Java and Node.js, payment integrations,
and SDK development. I enjoy solving practical problems—debugging production issues, improving performance,
and writing code that other engineers can understand and maintain.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Language

English

Fluent

Work Experience

Software Engineer (Contract) at Paygate

February 1, 2025 - Present

Designed and built a React + TypeScript payment checkout SDK used by merchants to accept payments via Cards, USD, Bank Transfer, OPay, Palm Pay, Kuda, Mobile Money, and NQR. SDK embeddable and framework-agnostic, supporting CDN usage and npm distribution. Implemented secure payment flows using AES-GCM encryption, pay load signing, Base64 encoding, and backend verification. Developed multi-step checkout flows with OTP handling, expiry timers, validation, and recovery from failed transactions. Implemented multi-currency and multi-country support (NGN, GHS, KES, ZAR, USD, EUR) with locale-aware formatting. Refactored a large checkout component into reusable sub-components without breaking existing integrations. Resolved production issues including timezone-related payment expiry, UTF-8 decoding errors, browser compatibility problems, and Rollup bundling constraints. Wrote and maintained SDK documentation and versioned releases while maintaining backward compatibility.

Full-Stack Engineer (Software Engineer) at Internet Brands

October 1, 2023 - Present

Full-stack engineer building, maintaining, and debugging multiple production applications within Manager Center and Exchange. Investigated layout and interaction issues, collaborating closely with designers and QA to reproduce and resolve problems. Built and shipped new frontend screens and internal tools using React, TypeScript, Redux, and styled-components. Contributed to backend services written in Java 8, Spring, Groovy, and Jetty. Wrote and optimized native SQL queries to improve data access and performance. Participated in sprint planning, estimation, and code reviews as part of an Agile team.

Python Developer (Contract) at CyberMe Studio

October 1, 2022 - January 31, 2023

Worked with a distributed team to build malware and firmware scanning solution used by private organizations. Contributed to a Django backend and a React + TypeScript frontend. Improved test coverage from ~30% to 98% by writing unit, integration, and end-to-end tests. Fixed critical bugs that significantly improved system stability and reliability.

Open Source Fellow (G-Research) at Major League Hacking Fellowship

June 1, 2022 - September 30, 2022

Contributed to G-Research open-source Armada project. Improved and reorganized technical documentation, reducing onboarding time for new contributors. Fixed reported GitHub issues, addressed npm vulnerabilities, and implemented frontend improvements. Gained experience working in distributed OSS teams with CI workflows.

Software Engineer (R&D) at LearnSpace

March 1, 2021 - October 1, 2023

Spearheaded frontend development for a hybrid fintech platform that has funded 500+ students, connecting impact investors with learners seeking financial aid for tech programs. Built with ReactJS and a Java-based centralized backend.

Java Developer | Database Administrator (Contract) at BrandX Patron

March 1, 2020 - May 31, 2021

Migrated a legacy Sybase database to MySQL for improved scalability and performance. Built backend services using Java EE to support the new data layer. Wrote comprehensive unit and integration tests, significantly reducing production issues.

Software Engineer at LearnersCorner

April 1, 2019 - February 1, 2021

Built and maintained core features for the public portal; led development of client-facing interfaces with Next.js, ReactJS, Redux, and Tailwind CSS; implemented admin and student portals with location-based tracking during sign-up and login; designed and integrated key features such as notifications, user authentication, and secure payments using Node.js (NestJS), PostgreSQL (Prisma ORM), and Paystack APIs.

Junior Web Developer (Internship / Part-Time) at ToLet.com.ng

January 1, 2015 - March 1, 2019

Assisted in building and maintaining dynamic property listing pages using HTML, CSS, and JavaScript. Developed internal tools with Node.js and Express, including lead tracking and admin dashboards. Integrated third-party services such as Google Maps, Mailgun, and geolocation APIs. Helped build a lightweight CMS for managing blog content and marketing materials. Fixed UI bugs, improved page responsiveness, and supported deployments via cPanel. Participated in code reviews, stand-ups, and product discussions with the engineering team.