// available for select work
Owolabi Oluwatosin Daniel
Senior Full-Stack Engineer — Real-time platforms · Fintech · AI products
I build production-grade web and mobile platforms end to end — from database schema and real-time backends to the UI clients ship. Founding engineer behind PlayZeet, a live peer-to-peer sports-betting platform serving real money at scale.
- ✦Founding engineer — built PlayZeet end to end
- ✦Real-time systems: Socket.IO, BullMQ, Redis
- ✦Fintech-grade settlement & payments
Testimonials
What clients say
“Daniel is very experienced and resourceful. He communicates well, brainstorms ideas with me, and comes up with great solutions. He meets deadlines, and I consider his skills exceptional. He also implemented a caching mechanism that updates every minute to improve performance. I will work with him again.”
“Excellent experience in working with Daniel. He understood the requirements clearly and came up with multiple approaches and finally got the task done.”
“Has proven himself to be efficient in CSS, I will definitely use his services again in the future”
“Daniel is very experienced and resourceful. He communicates well, brainstorms ideas with me, and comes up with great solutions. He meets deadlines, and I consider his skills exceptional. He also implemented a caching mechanism that updates every minute to improve performance. I will work with him again.”
“Excellent experience in working with Daniel. He understood the requirements clearly and came up with multiple approaches and finally got the task done.”
“Has proven himself to be efficient in CSS, I will definitely use his services again in the future”
Selected work
Featured projects
Production platforms I've built and shipped — most of them handling real users or real money.
PlayZeet
Peer-to-peer sports betting platform
Founding engineer on a peer-to-peer, group, and novelty sports-betting platform. Owned frontend and backend end to end: bet-matching engine (lay bets, brave-take applicability, currency-equivalence logic), a pari-mutuel payout formula for group bets, a scheduled settlement job, JWT session management with multi-layer expiry detection, and a Puppeteer-based SSR/SEO layer for the React SPA. Integrated crypto (NOWPayments) and card (Flutterwave) deposits with BullMQ reconciliation.
PlayZeet Blog & CMS
SEO-ready React blog with role-based CMS
A full-stack blog and content platform for PlayZeet, built as a React + NestJS monorepo and containerized with Docker. Solves the SEO problem inherent to client-rendered React through server-side rendering/prerendering, and ships a CMS with role-based admin authentication for content management.
Esdiac Global System Inc.
Video Calling Web Application and Telecom Provider
Over nearly four years at Esdiac Global Systems Inc., I've built mobile and web applications across the company's product suite — including video calling solutions, a security agency app, the Provider App, the core Esdiac app, and Esdiac Payment. Working remotely alongside the CTO and the wider team, I've delivered these projects end-to-end while continually sharpening my skills across a range of technologies.
VitaScan
Health-monitoring mobile app
A React Native (Expo) health-monitoring app with native voice guidance. Built the client and resolved native module registration for on-device speech after EAS builds.
Deep dives
Case studies
How specific systems got built — the problem, the decisions, and the outcome.
Toolbox
Tech stack
The tools I reach for to build scalable, maintainable systems.
Writing
Recent posts
Notes from the codebase — the bugs, the architecture calls, the lessons.
The settlement job that quietly wrote NaN: a Prisma Decimal post-mortem
How PlayZeet's bet-settlement job started writing amount: NaN with no error, why Prisma.Decimal arithmetic silently coerces, and the boundary fix that closed the whole class of bug.
Integrating NOWPayments crypto payments in NestJS without double-crediting wallets
A production guide to NOWPayments in NestJS: verifying IPN webhooks (the sorted-key HMAC-SHA512 gotcha), idempotent wallet crediting, BullMQ reconciliation, and whitelist + TOTP payouts.
Peer-to-peer betting is a correctness problem wearing a socket costume
The real architecture behind a P2P betting backend: a matching engine that never double-matches, an idempotent pari-mutuel settlement job, and a BullMQ + Redis queue layer that makes webhooks safe to replay.
Ship notes
Real work in progress: what I'm building, learning, and shipping.
Let's talk
Got a system to build — or a broken one to fix?
I take on a small number of projects at a time so each one gets real attention. If you're building something ambitious, let's scope it.