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Josiah Onyeje

@josiahonyeje

Backend software engineer at Suntrust Bank who built secure banking APIs and launched JobiHub, a live recruitment platform.

Nigeria

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What I'm looking for

I'm open to remote, on-site, hybrid, and contract opportunities, as well as relocation.

At Suntrust Bank, I designed and built ASP.NET Core APIs for core banking workflows and owned backend services supporting secure financial transactions. I also tuned SQL queries and stored procedures for production banking workloads.

On freelance projects, I launched JobiHub, a live career and recruitment platform, handling product design, full-stack development, deployment, and its supporting infrastructure. I built its React and TypeScript frontend and .NET API, backed by PostgreSQL.

I’ve also built payment and banking services, including a CoralPay interbank transaction platform with PGP encryption and digital signature verification, and virtual card middleware integrating Interswitch APIs. My work has included transaction validation, reconciliation, and secure API integrations.

I’m currently a part-time freelance backend engineer and technical mentor. I’ve also developed a school management platform and regulatory reporting systems, including data ingestion processing over 2,000 daily transaction records.

Experience

Work history, roles, and key accomplishments

Current

Technical Mentor / Coding Instructor

Current

Self-Employed

Jan 2026 - Present (9 months)

Provide 1-on-1 mentoring and code review for developers learning .NET/C#, covering backend fundamentals, API design, and career readiness.

C#.NET API Design Code Review Mentorship

Current

Independent Backend Software Engineer

Current

Self-Employed

Jan 2023 - Present (3 years 9 months)

Conceived software products from business ideas and independently delivered complete applications from architecture through production deployment. Launched JobiHub, a live two-sided recruitment platform, and built a Kafka-based background service for encrypted SMS/notification delivery.

C#.NET ASP.NET Core Kafka RabbitMQ SQL Server PostgreSQL Render Swagger OpenAPI React TypeScript Cloudinary Resend

Backend Software Engineer (.NET)

Suntrust Bank

Aug 2024 - Jun 2026 (1 year 10 months)

Designed and built ASP.NET Core Web APIs for core banking workflows, applying SOLID principles and Clean Architecture. Wrote and tuned SQL queries and stored procedures for high-volume financial transaction processing, and implemented structured logging with Serilog.

ASP.NET Core C#.NET SQL Stored Procedures Serilog CI CD Git React HTML CSS JavaScript Agile Scrum

Professional Development & Technical Training

Self-Directed

Feb 2021 - Jan 2023 (1 year 11 months)

Completed intensive, self-directed training in C# and .NET, building real applications around REST APIs, database integration, authentication, and backend architecture.

C#.NET ASP.NET Core Entity Framework Core SQL Server PostgreSQL

IT Support Intern

National Primary Health Care Development Agency (NPHCDA)

Jan 2020 - Dec 2020 (11 months)

Provided technical support for computer systems and network infrastructure, resolving hardware and software issues. Performed system monitoring, software installations, and basic database management.

Technical Support System Monitoring Software Installation Database Management