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Isaac Oluwayinka, Software Engineer & Architect

I design and build complete systems: cloud architecture, APIs, web platforms and mobile apps.

I've shipped production software for over seven years. Today I lead engineering for Lone Star Civil's AI-powered platform on AWS: NestJS, PostgreSQL, document processing and zero-downtime deploys.

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Have a project in mind? I build and fix websites and apps. Ask for a free consultation.

Isaac Oluwayinka, smiling with arms folded, in a dark blazer and a striped shirt
7+
years shipping production software
Freelance from February 2019, then employed roles
85+
client web applications delivered
All my work, 2019 to now
2200+
API endpoints built
Across everything I have built, 2019 to now

Things I have built

Some of the work I can talk about, and what I did on each.

All the work

One of the systems I run today, drawn simply

A web platform on AWS. Requests come in at the left; storage and the services it leans on are at the right; the bottom row is how a change reaches production without anyone noticing.

A cloud platform, simplifiedA web app sends requests over HTTPS to a load balancer, which passes them to a NestJS API running on AWS ECS Fargate. The API reads and writes an Aurora Serverless PostgreSQL database, stores uploaded files in S3, streams answers from the Claude API and looks up market prices with Tavily. Code is built by CodeBuild, packaged as images in ECR and deployed to the API without downtime.HTTPSimagesdeploys, no downtimeWeb appLoad balancerAWS ALBAPINestJS on ECS FargateDatabaseAurora Serverless v2File storageS3, signed uploadsClaude APIstreaming, tool useTavilymarket pricesCodeBuildbuilds and testsECRcontainer images

Swipe the drawing sideways. Simplified. The real thing has more moving parts.

What I do

Software architecture

Systems designed around their failure modes, with every decision written down.

I design the whole system before anyone writes code: where data lives, what can fail, how it recovers, and how it is deployed without downtime. Multi-tenant isolation, queues, outbox patterns and cloud topology are things I have built and run, not only drawn.

AWS ECS Fargate, Aurora Serverless v2, Multi-tenancy, CI/CD, ADRs

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Backend engineering

APIs and background jobs that are secure, idempotent and observable.

I build REST APIs and the machinery behind them: authentication, role-based access, job queues, streaming responses and third-party integrations. The API I lead today has more than fifty endpoints and isolates each company's data.

NestJS, Node.js, PostgreSQL, Prisma, JWT and RBAC, SSE streaming

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Full-stack web

Fast, accessible products, from interface to infrastructure.

I have built web applications for clients in education, e-commerce and logistics, and I carry one from the interface through the API to the deployment. I care about load time and accessibility because users notice both.

Next.js, React, TypeScript, Tailwind CSS, Node.js, Laravel

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Mobile apps

Native mobile apps for Android and iOS that stay reliable under real-device limits.

I build native mobile apps for Android and iOS. On Android I write Kotlin and Jetpack Compose; on iOS, Swift with SwiftUI and UIKit. The parts I care about are the ones that break on real phones: offline data, background work, notifications under battery limits and performance on low-memory devices.

Kotlin, Jetpack Compose, Room, WorkManager, Coroutines and Flow, Swift, SwiftUI, UIKit, Combine, Core Data

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Where I have worked

  1. Neli Arabi GmbH

    Lead Backend Engineer and pod lead

    Apr 2026 to Oct 2026, Berlin, Germany (remote)

    I led a backend pod building a B2B ERP platform for complex multi-entity operations.

    • Led the pod from April to October 2026.
    • Helped build the platform's structured workflows, data control, integrations and reporting.
    • Built private enterprise review into the platform.

  2. Lone Star Civil

    IT Manager and Lead Software Engineer

    Mar 2025 to now, San Antonio, Texas (remote)

    I lead the design, build and deployment of a contractor-management platform with AI features, and I own the company's software and cloud infrastructure.

    • Run the backend on AWS ECS Fargate with Aurora Serverless v2 PostgreSQL, S3 and CodeBuild pipelines, deploying without downtime.
    • Built a NestJS and TypeScript REST API with more than 50 endpoints, JWT authentication, role-based access and per-company data isolation.
    • Added features on the Claude API: streamed answers, tool use and document processing for PDF, DOCX, XLSX and images, leading to automated bids, cost estimates and price comparison.
    • Model the data in Prisma on PostgreSQL, including schema design, query tuning and migrations for construction-domain data.

  3. TheSlimPrep

    Part-time Software Engineer

    May 2024 to Mar 2026, Canada (remote)

    I built web applications and REST APIs for several platforms on a multi-tenant architecture, alongside my full-time work.

    • Built web apps and REST APIs in Node.js and React for multiple platforms on a multi-tenant architecture.
    • Designed SQL schemas and indexes, improving data retrieval performance by 40%.
    • Set up Docker development environments and deployment workflows, which sped up onboarding and made CI/CD reproducible.
    • Added JWT authentication and role-based access to multi-tenant SaaS features.
    • Worked in a cross-functional Agile team.

  4. Independent

    Full-stack developer and consultant

    Feb 2019 to Mar 2023, Remote

    Delivered web applications for clients in education, e-commerce and logistics, from architecture to deployment.

    • Wrote custom backends in PHP with Laravel and in Node.js: authentication, admin dashboards, reporting and API integrations.
    • Deployed on AWS with DNS, SSL, Nginx and automated backups.
    • Advised small businesses on technical architecture as they moved online.

Advice, in plain words

Short articles for people who need a website or an app and are not technical.

  • Why is my website slow?

    · 3 min read · Keeping it healthy

    Slow websites are usually slow for a few ordinary reasons: big pictures, too many add-ons, struggling hosting. Here is how to check and what fixes it.

  • What to prepare before you hire a developer

    · 3 min read · Planning your project

    You need less than you think. A few sentences about what you want, who it is for and what you like. Here is what helps, and what to ask.

  • What is an MVP, and do I need one?

    · 3 min read · Planning your project

    An MVP is the smallest version of your idea that real people can use. It shows you whether the idea works before you build all of it.

All the articles

Let's talk

A role, a project or a question. Send me a line and I will reply.

Not sure where to start? Tell me about your project. Ask for a free consultation.

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Prefer a form? Write to me here.