Available for remote roles

Ziregbe Otee Senior Full Stack .NET Developer

Backend-first engineer with 15+ years building scalable, high-performance systems across fintech, healthcare, education, and government sectors.

View Projects Get in Touch
>_ C# · .NET 9 · Python · Azure / AWS · PostgreSQL · React · Clean Architecture
About

Building systems that scale

I'm a Senior Full Stack .NET Developer with 15+ years delivering production systems across fintech, healthcare, education, and government. My core expertise is backend architecture — designing clean, maintainable systems with C#, .NET, and Azure — but I'm equally comfortable taking a feature end-to-end from database schema to polished UI.

I've built and led teams across Nigeria, Serbia, and the US (remote), shipping everything from payment gateways processing millions in transactions to a nationwide EHR system serving 5,000+ staff. My most recent work is Zipa — a live commercial hyperlocal delivery platform I architected and built solo from scratch.

I'm also AI/ML capable, having completed a Post Graduate Program in AI/ML & Business Analytics at the University of Texas at Arlington, and I'm actively building NaijaTax.ai — an LLM-powered tax advisory tool for the Nigerian market combining RAG architecture with domain-specific fine-tuning.

15+ Years Experience
8+ Industry Sectors
3 Countries (Remote)
50% CyberPay Transaction Growth
// Key Achievements
⚡
12 hours → 5 minutes

Reduced WAEC result processing time via bulk insert and in-memory transposing — powering results for millions of West African students.

📈
50% Transaction Growth

Extended CyberPay Payment Gateway with additional payment channels at Cyberspace Limited, driving a measurable 50% increase in processed transactions.

🏥
Nationwide EHR System

Led architecture and delivery of an EHR & inventory system for ~5,000 staff across all primary health centres in Nigeria at PlateauMed.

Skills

Technology Stack

⚙ Backend

C# .NET 9 / 8 / 7 / 6 ASP.NET Core Web API Entity Framework Core Hangfire Python Akka.NET SignalR ABP.io / ASP.NET Zero

🏗 Architecture

Clean Architecture Microservices CQRS / MediatR DDD Event-Driven REST API Design TDD / xUnit / NUnit

📊 Data

PostgreSQL SQL Server MySQL Azure Redis Elasticsearch Metabase

⛅ Cloud & DevOps

Azure Azure DevOps Docker CI/CD Azure App Service Azure Blob Storage Azure Key Vault Railway Vercel

🔒 Auth & Security

Identity Server JWT OAuth 2.0 OTP / SMS Auth Iron-session Refresh Token Rotation

💻 Frontend

React Next.js 14 Blazor TypeScript JavaScript Material UI Tailwind CSS

🤖 AI / ML

LLM Integration RAG Architecture Fine-tuning Claude API Business Analytics ML Pipelines

🔌 Integrations

Stripe / Paystack Cloudinary US Broker APIs Claude Haiku Bank Transfer Metabase Analytics
Experience

Career Timeline

Principal Software Engineer

Zipa Digital Solutions Limited
2026 – Present Current

Hyperlocal delivery and errand platform — zipa.ng

  • Architected and built the full platform solo — customer PWA, business PWA, rider PWA, and admin dashboard.
  • Designed a multi-role .NET 9 REST API handling order management, delivery assignment, real-time notifications, and Paystack payment processing.
  • Implemented OTP-based authentication with JWT + refresh token rotation and Iron-session-managed frontend sessions.
  • Integrated Termii (SMS/OTP), Cloudinary (image hosting), and Paystack (payments + payouts) into a cohesive delivery pipeline.
  • Built a chat-to-order feature enabling conversational ordering for pharmacy and specialty merchants.
  • Launched commercially in March 2026; onboarded 10+ merchants and 50+ users within six weeks.
.NET 9 C# Next.js 14 TypeScript PostgreSQL EF Core Hangfire Paystack Termii Railway Vercel

NaijaTax AI — RAG-based Nigerian tax research assistant, live at naijatax.ai

  • Built a full RAG pipeline over Nigeria's 2025 Tax Act & Tax Administration Act corpus (595 chunks, pgvector cosine similarity).
  • Provisioned production AWS infrastructure via CDK — two-AZ VPC, ECS Fargate, RDS Postgres 17 + pgvector, ALB/HTTPS, CloudFront + S3.
  • Implemented confidence-gated retrieval and deterministic citation formatting to reduce hallucination and unsupported citations.
  • Built IP-partitioned rate limiting middleware, architected for authenticated-tier scaling.
.NET 9 ASP.NET Core Next.js 14 PostgreSQL + pgvector OpenAI GPT-4o AWS CDK Azure Document Intelligence

Lead Software Engineer

Urvin Finance — United States (Remote)
2021 – 2026

Financial social platform serving thousands of active users, built from scratch.

  • Designed and led development of the full platform — backend APIs, frontend components, and Azure cloud infrastructure.
  • Restructured portfolio data store, improving backend response time by 20%.
  • Integrated third-party broker providers to synchronise user portfolios in real time.
  • Hardened platform security against session hijacking, clickjacking, and mass assignment vulnerabilities.
.NET 7 Blazor Clean Architecture MediatR Identity Server PostgreSQL Azure Redis Elasticsearch Azure DevOps

Fullstack Developer

PlateauMed — Nigeria
2024 – May 2025

EHR & Inventory system for ~5,000 staff across all primary health centres in Nigeria.

  • Led full-stack architecture and codebase setup for a nationwide inventory management system.
  • Built high-throughput API endpoints with query optimisation and integrated Metabase for analytics reporting.
  • Delivered React frontend interfacing with secure, scalable .NET backend services.
.NET 7 ASP.NET Zero React PostgreSQL MediatR Azure Redis Azure Blob Storage

Team Lead / Senior Software Engineer

MVP-Soft — Serbia (Remote)
2022 – 2023

Enterprise CRM solution built from scratch.

  • Led a team of 3 developers delivering a full CRM product — from API design to React UI components.
  • Built a billing module with bulk SQL insert, cutting bill upload time by 50%.
  • Designed high-throughput API endpoints and polished Material UI frontend components.
.NET 6 React Material UI MS SQL Server MediatR Clean Architecture DDD

Deputy Chief Software Architect

Cyberspace Limited — Nigeria
2019 – 2021

Unit Head of Fintech Division — CyberPay Payment Gateway.

  • Extended CyberPay with additional payment channels, driving a 50% increase in transactions.
  • Led development of an e-learning solution; enforced git workflows, code reviews, and branch policies.
  • Set up and monitored CI/CD pipelines and Azure infrastructure for the fintech division.
ASP.NET Core Akka.NET React NodeJS Identity Server Azure Azure DevOps

Senior Software Engineer

Vatebra Limited — Nigeria
2015 – 2019

Team Lead — Government & Educational Solutions (WAEC, Edo State, West Africa).

  • Reduced WAEC result processing time from 12 hours to 5 minutes via bulk insert and in-memory result transposing.
  • Designed and implemented Edo State Lottery Tax System, WAEC Sierra Leone Result Verification & PIN Vending, and WAEC Ghana Item Banking.
  • Built an LTI-compliant eLearning solution (Scholar Room).
ASP.NET MVC 5 ASP.NET Core Web API 2 SQL Server Telerik Kendo UI

Senior Software Engineer

Zitech Information Systems — Nigeria
2012 – 2015
  • Designed and built a job board, personality portal, and test management system (TMS).
ASP.NET Webforms C# Entity Framework SQL Server Telerik

Software Engineer

Dragnet Solutions — Nigeria
2008 – 2012
  • Built computer-based testing solutions including a Keirsey temperament sorter, SQL Server backup utility, and customisable job application portals.
ASP.NET Webforms C# SQL Server Telerik
Projects

Featured Work

Zipa

Live Commercial Sole Engineer
zipa.ng ↗

Hyperlocal delivery and errand platform built from scratch as sole engineer. Full multi-role platform covering customers, businesses, riders, and admin operations across Nigeria. Launched commercially in March 2026.

  • Customer, business, and rider PWAs + admin dashboard
  • Real-time order management, delivery assignment & tracking
  • Chat-to-order for pharmacy and specialty merchants
  • OTP-based auth with JWT + refresh token rotation
  • 10+ merchants, 50+ users — within 6 weeks of launch
.NET 9 Next.js 14 TypeScript PostgreSQL EF Core Hangfire Paystack Termii Cloudinary Railway Vercel

NaijaTax.ai

Live
naijatax.ai ↗

RAG-based Nigerian tax research assistant, live at naijatax.ai. Built under Zipa Digital Solutions Limited — a full retrieval-augmented generation pipeline over Nigeria's 2025 Tax Act and Tax Administration Act corpus, deployed on production AWS infrastructure.

  • RAG pipeline over a 595-chunk Nigerian tax corpus (pgvector cosine similarity)
  • Production AWS infrastructure via CDK — ECS Fargate, RDS Postgres 17, CloudFront + S3
  • Confidence-gated retrieval & deterministic citations to reduce hallucination
  • IP-partitioned rate limiting middleware
.NET 9 ASP.NET Core Next.js 14 PostgreSQL + pgvector OpenAI GPT-4o AWS CDK Azure Document Intelligence

AI/ML ePortfolio

Verified Academic
View Portfolio ↗

Hands-on AI/ML projects completed during the Post Graduate Program in AI/ML & Business Analytics at the University of Texas at Arlington, in partnership with Great Learning.

  • Applied machine learning, deep learning, and business analytics
  • Real-world case studies across multiple domains
  • Foundations for LLM and RAG work in NaijaTax.ai
Python Machine Learning Deep Learning Business Analytics UT Arlington
Certifications

Professional Certifications

🏆

AWS Certified Solutions Architect – Associate

🏆

MCP — Microsoft Certified Professional

🏆

Microsoft Specialist: Developing ASP.NET MVC Web Applications

🏆

Microsoft Certified Solutions Developer: Web Applications

🏆

MCTS: SQL Server 2008 Database Development (70-433)

🏆

Microsoft Specialist: Programming in HTML5 with JavaScript and CSS3

🏆

Microsoft Specialist: .NET Framework — Application Development Foundation

// Education
2024 – 2025

Post Graduate Program in AI/ML & Business Analytics

University of Texas at Arlington View AI ePortfolio ↗
1999 – 2004

B.Eng, Mechanical Engineering

University of Benin, Nigeria
Contact

Let’s Connect

Open to senior .NET backend roles, full-stack positions, and technical leadership opportunities — remote preferred.

Email otee@zitechng.com
GitHub github.com/oteebest
LinkedIn linkedin.com/in/ziregbe-otee
Stack Overflow stackoverflow.com/users/4547957