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Opeoluwa Siyanbola

@opeoluwasiyanbola

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I build scalable, AI, web, and mobile products with React, React Native, Node.js, and cloud infrastructure.

Nigeria

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What I'm looking for

I'm looking to build scalable, high-performance products across fintech, AI, web, or mobile, contributing to secure systems, strong user experiences, and reliable engineering practices.

I've built full-stack products for Pastel Africa, Turing, Topcoder, Spoxio, and Startupia across fintech, AI, pharma, content, and sports. My work spans secure payment systems, AI-assisted fraud detection, LLM evaluation, and cross-platform applications.

At Pastel Africa, I implemented AI-assisted fraud detection and real-time transaction-risk monitoring, multi-application dashboards with centralized authentication, and payment-routing systems that improve transaction success and uptime. I also developed secure integrations with banking systems, payment gateways, and financial service providers for high-volume processing.

At Turing, I helped improve Google Gemini through human-in-the-loop training, evaluating AI-generated TypeScript code, testing model-generated solutions, and producing structured feedback for safer, more reliable LLM behavior.

I've also delivered React, Next.js, Node.js, Express, and React Native applications for a global pharmaceutical enterprise, a sports platform, and fintech products including agricultural matching, fundraising, KYC, and peer-to-peer cryptocurrency exchange systems.

Experience

Work history, roles, and key accomplishments

Full Stack Developer

Pastel Africa

Jan 2023 - Jul 2026 (3 years 6 months)

Implemented AI-assisted fraud detection and real-time transaction risk monitoring. Designed a multi-application dashboard with centralized authentication and permission management.

React Native TypeScript Redux React Query Shadcn Ui REST APIs AWS MongoDB PostgreSQL Redis GitHub Actions AI Fraud Detection RBAC Payment Systems

Senior Software Engineer - LLM Training

Turing

Jan 2024 - Feb 2026 (2 years 1 month)

Contributed to LLM training by simulating software engineering workflows and evaluating AI model performance. Designed and executed tests to validate model-generated solutions.

LLM Human In The Loop Prompt Engineering TypeScript Python Unit Testing Integration Testing Code Review Debugging

Mobile Developer

Spoxio

Nov 2021 - Aug 2023 (1 year 9 months)

Developed and maintained a cross-platform mobile application using React Native. Implemented CI/CD pipelines with App Center and automated deployments.

React Native CI CD GitHub Actions CircleCi Mobile Development Performance Optimization

Fullstack Developer

Topcoder

Jan 2022 - Jan 2023 (1 year)

Developed responsive web applications using React, Next.js, and TypeScript for a pharmaceutical enterprise. Built backend services with Node.js and Express, and implemented testing with Jest.

React Next.js TypeScript Ant Design Node Express REST APIs Jest React Testing Library Agile DevOps Security

Full Stack Developer

Startupia

Sep 2018 - Jul 2021 (2 years 10 months)

Engineered backend for an agricultural matching platform using Express. Implemented payment integrations, KYC processes, and a peer-to-peer cryptocurrency exchange.

Express Payment Integration KYC Blockchain Cryptocurrency WebSockets Fintech MongoDB