Olusegun Banji
Full Stack Engineer & Team Lead
I build dependable platforms and lead the teams and communities behind them. Currently leading full stack engineering at MangoZest Labs and building as a Senior Full Stack Engineer at Cliniec Health Solutions.
React.js • Node.js • NestJS • Next.js • Django • TypeScript
About
Hello, I'm Olusegun Banji
I build AI-powered software for people most products quietly leave out, and I lead the teams that build it. Right now I lead full stack engineering on Andromeda, a hospitality and travel platform, at MangoZest Labs, work as a Senior Full Stack Engineer at Cliniec Health Solutions, and am CEO and Lead Software Engineer of two ventures: AfriMentor AI and Scarce2plenty, an agricultural crowdfunding and marketplace platform that connects farmers directly with buyers.
AfriMentor AI began as my MSSE capstone: a smartphone-first, voice-note-driven LLM mentor for low-income African entrepreneurs, built for low-end Android phones and patchy 3G networks. I led the four-person, three-country team behind it. Our research found that automatic LLM-as-judge scores and blinded human ratings of persona quality disagree, which matters for anyone evaluating persona-aligned models. Both papers are being prepared for arXiv.
Beyond the day job, I'm a community builder. With Indigitous I founded and lead the Ife chapter, lead the South West region, and served as a National Indigitous Mobilizer. At Cospire, my work on a 5-step booking flow lifted completion by 50% and revenue by 20%. I put as much energy into coaching teammates toward their next steps as into the code.
I'm completing an MSSE at Quantic School of Business and Technology (Distinction expected September 2026) and hold a BSc in Computer Science with Economics from Obafemi Awolowo University (2024).
Services
Web Development
Building robust and scalable web applications with full-stack backends and slick frontends
API & Backend Integration
Crafting secure and maintainable APIs, handling authentication, databases, and business logic
PWA & UX Enhancement
Designing Progressive Web Apps with smooth interactivity and offline readiness
Skills
Experience
Senior Full Stack Engineer
Cliniec Health Solutions · Remote
• Converted the Cliniec product into a pnpm/Turborepo monorepo of seven Next.js apps and shared packages (UI kit, typed API client, geo data, config)
• Built the Pharmacy, Lab and Hospital portals from Figma designs, including dashboards, appointments, results, messaging and reports, and wired the Hospital app to the hospital API
• Redesigned the public marketing site and built its portal picker for each vertical
• Set up Vercel deployments and a GitHub Actions workflow that mirrors main to a deploy repository
• Addressed code-review findings, including a timezone bug, swallowed errors and CI coverage
CEO and Lead Software Engineer
AfriMentor AI · Remote
• CEO and Lead Software Engineer of AfriMentor AI, an LLM mentorship platform for low-income African micro-entrepreneurs that began as my MSSE capstone; smartphone-first and voice-note-driven
• Lead the engineering of a 13-microservice, event-driven system (Next.js 16, FastAPI, PostgreSQL, ChromaDB hybrid dense + BM25 retrieval) with a PWA built for low-end Android devices and unreliable connectivity
• Lead the RLHF/DPO persona-consistency alignment work on Qwen2.5-7B-Instruct (4-bit NF4 quantization, LoRA), with two research papers in preparation for arXiv
• Cut infrastructure cost from about $4,500/month to near $0 by moving to Oracle's free-tier cloud
Lead Full Stack Software Engineer
MangoZest Labs
• Lead full stack engineering on Andromeda, a hospitality and travel platform
• Work across a Turborepo/pnpm monorepo of six Next.js portals backed by a NestJS, Prisma and PostgreSQL API
• Secure the admin portal with TOTP two-factor authentication
Research Software Engineer
Sep 2025 - Jan 2026 · Virtual Call Center
• Contributed to research and development of backend and AI infrastructure for a Virtual Call Center
• Designed the system architecture for a proposed self-hosted AI engine and acted as the bridge between the system under active development and the proposed engine
• Published OpenAPI/Swagger documentation for the Virtual Call Center and Andromeda backends
• Collaborated with cross-functional teams to integrate new technologies into existing services
CEO and Lead Software Engineer
Scarce2plenty · Remote
• CEO and Lead Software Engineer of Scarce2plenty, an agricultural crowdfunding and marketplace platform connecting farmers directly with buyers
• Built the platform with React.js, Next.js, Firebase and TailwindCSS
• An early beta let smallholder farmers test fundraising models
Fullstack Engineer
Cospire
Previously Software Engineering Intern, Sep 2023 - Nov 2023
• Re-architected backend routing layer with Express.js, reducing API latency to sub-200ms
• Integrated 7+ external APIs (Firebase, Brevo, Google Maps, OpenStreetMap) to enhance platform services
• Led the development of a 5-step booking flow, boosting completion rate by 50%
• Optimized and secured SSO workflows with OAuth, cutting login errors by 60%
• Contributed to MVP2, helping secure 10+ early adopters and 3+ coworking partnerships
Key Achievements:
• Increased platform revenue by 20% through improved booking flow
• Reduced third-party request failures by 30% with resilient integrations
• Recognized by leadership for driving user adoption and platform growth
Software Engineer (Volunteer)
Indigitous
• Spearheaded development of a chatbot platform and real-time chat interface used by 500+ global users
• Integrated OAuth providers (Google and Facebook) to streamline user onboarding
• Built server-side rendered pages, improving SEO and page performance
• Designed and maintained a scalable social-media-like data model
Key Achievements:
• Reduced login drop-off by 35% with improved OAuth flows
• Increased page load performance by 45% and SEO ranking by 30%
• Co-led a 6-person dev team, achieving Top 8 placement in a global hackathon across 50+ cities
• Supported 1,000+ monthly social interactions through backend optimizations
Community Leadership
Indigitous
• Ife Indigitous Lead and Founder
Jan 2023 - Present• South West Indigitous Lead
Jan 2024 - Present• National Indigitous Mobilizer
Oct 2025 - Jul 2026AI/ML Engineer & Fullstack Developer
CISRG
• Built and deployed a GPT-2-based chatbot API handling 1,000+ monthly conversations across Messenger and Telegram
• Designed and implemented 10+ Flask RESTful endpoints with OAuth 2.0 authentication
• Fine-tuned LLM prompts to improve chatbot accuracy and retention
• Collaborated with a research team of 5+ on AI/ML projects
Key Achievements:
• Improved chatbot accuracy by ~40%, reducing user confusion
• Increased backend scalability and security through API design
• Co-authored 4 peer-reviewed publications, all scoring above 65% in external evaluations
Projects
Cliniec Health
A centralized healthcare technology platform for pharmacies, laboratories and hospitals, built as a pnpm and Turborepo monorepo of seven Next.js apps that share one design system and a typed API client.
Marketing Site
Public site with a portal picker for each vertical
Pharmacy Portal
Pharmacy and stores dashboard
Lab Portal
Labs and diagnostics: appointments, results, messages and directory
Hospital Portal
Hospitals and emergencies portal with departments and reports
In Progress
Specialist, patient and admin apps
Shared Packages
UI kit, typed API client, geo data and config
The sites above are live. The source is a private company repository, so get in touch if you would like a walkthrough.
AfriMentor AI
I led a four-person team across three countries to build AfriMentor AI, an AI-powered platform designed to work on low-end Android phones and 3G networks.
Architecture
13-microservice, event-driven system
Access
PWA built for low-end Android devices and 3G
AI alignment
RLHF/DPO persona alignment on Qwen2.5-7B
Cost
Infrastructure cost cut from about $4,500/mo to near $0
Andromeda
A curated Nigerian hospitality and travel platform, built as a Turborepo monorepo: six Next.js apps for customers, members, hosts, businesses, partners and internal staff, all sharing one design system and a typed NestJS API.
Storefront
Customer-facing discovery and booking
Account
Signed-in member area
Host
Vendor portal for bookings and payouts
Business
Corporate accounts portal
Partners
Partner portal
Admin
Staff console with mandatory two-factor auth
API
NestJS service with Prisma, PostgreSQL and OpenAPI docs
Shared packages
UI kit, auth, data layer, types and config
Source code, live demos and test access are shared on request
This project is deployed and working, but the repository and demo access are kept private. Reach out and I'll share the links and a walkthrough.
vcc-uat-backend-dev
Virtual Call Center API — UAT/staging with OpenAPI docs and conversational AI features
OpenAPI, Conversational AI, REST API
andromedadev-backend
API documentation for Andromeda platform backend (developer docs)
API, OpenAPI/Swagger
poll-systems-backend
A Django backend for election polls
Django, PostgreSQL, Docker, REST API
Scarce2plenty
A crowd funding for agricultural goods sales app
React.js, Next.js, Firebase, TailwindCSS
Light Within Her
An blog website for healing, therapy and spiritual growth
Next.js, TailwindCSS, Sanity CMS
Apologist Chatbot Project
An AI-powered apologetics chatbot SAS
AI APIs (OpenAI), Next.js, Firebase/Auth
Indigitous Search Engine
A Non-copyrighted Search Application
Next.js, TailwindCSS, Custom APIs
Koinonia Divine Initiative Website
An official website for an international Christian NGO
React.js, Next.js, TailwindCSS
Blogging CRUD API Tutorial
A Blog CRUD Application
NestJS, TypeScript, REST API
SpaceX
A customized SpaceX landing page from their API
React, SpaceX API, Responsive Design
Tree of wally
A social media popularity monitization API
Node.js, Express, API Development
Medium Clone
A clone of medium.com
Next.js, Sanity CMS, TailwindCSS
Cospire
A B2B Space listing and booking startup
React.js, Node.js, Firebase, Google Maps
WhatsApp Web Clone
A clone of WhatsApp web
React, Firebase, Real-time Database
Growthbot PWA
Christian Discipleship Chatbot and Discipler connect App
React, PWA, Chatbot logic
Case Studies
Virtual Call Center — UAT / Conversational AI
Problem:
Businesses needed scalable, multilingual customer support with intelligent routing and analytics.
Solution:
Contributed to a Virtual Call Center API with OpenAPI docs, conversational AI, call transcription, and omnichannel support, working as part of the MangoZest Labs team.
Tech Stack:
OpenAPI, REST, Conversational AI, Transcription
Impact:
Supports automated handling of inbound and outbound customer interactions.
Andromeda Backend — API Docs & JWT Auth
Problem:
Developers needed clear, secure backend APIs with authentication and health checks.
Solution:
Provided OpenAPI documentation for the Andromeda backend with JWT-based auth and comprehensive endpoint definitions.
Tech Stack:
OpenAPI, JWT Auth, REST API, Health Endpoints
Impact:
Improved developer onboarding and faster integration using documented endpoints and auth flows.
Scarce2plenty — Agricultural Crowdfunding Platform
Problem:
Farmers lacked direct channels to market agricultural goods, facing middlemen costs.
Solution:
Built a crowdfunding/marketplace app enabling direct farmer-to-buyer sales.
Tech Stack:
React.js, Next.js, Firebase, TailwindCSS
Impact:
Improved farmer visibility; early beta allowed smallholder farmers to test fundraising models.
Light Within Her — Blog for Healing & Therapy
Problem:
Many individuals lacked an accessible platform for therapy and spiritual growth resources.
Solution:
Developed a blog site with easy CMS management and responsive layouts.
Tech Stack:
Next.js, Sanity CMS, TailwindCSS
Impact:
Empowered writers to publish quickly; grew community readership within first months.
Poll-systems-backend — Election Polling System
Problem:
Election systems needed transparent, secure backend APIs.
Solution:
Built Django-based backend with endpoints for polls, votes, and authentication.
Tech Stack:
Django, Python, PostgreSQL, REST Framework
Impact:
Enabled demo polling app; Loom walkthrough used in presentations for civic tech.
Feed Posts
Building Scalable React Applications
Best practices for structuring large React applications with proper state management and component architecture.
NestJS vs Express: A Developer's Perspective
Comparing two popular Node.js frameworks and when to choose each for your next project.
Firebase vs Supabase: The Database Showdown
A comprehensive comparison of two popular Backend-as-a-Service platforms for modern web applications.
Hire Me
I lead engineering work and build products that people can rely on. If you have a project, a team or a community that could use that, I'd love to hear about it.
Let's Start a Conversation
Message me on WhatsApp for quick responses and project discussions
Availability
Open to the right opportunity
Response Time
Within 24 hours
Time Zone
WAT (UTC+1)
Contact
Let's Connect
Ready to bring your ideas to life? I'm available for new projects and collaborations. Let's discuss how we can work together to create something amazing.