Full-stack engineer. I build the parts of a product people see — interfaces, flows, dashboards — and the parts they should never have to think about: payment infrastructure, reconciliation, compliance.

Frontend in React and TypeScript. Mobile in React Native and Flutter, down to Kotlin and Swift where the platform makes you — and native Swift outright when the platform is the point. Backends in Go, C#, Python and Node. Postgres underneath.

Portfolio · LinkedIn · Twitter · nobleconcepts22@gmail.com

Four services a fintech needs at the edges of its ledger. Each does one job and refuses to do the rest — none of them can move money, by construction.

Verifies each provider's signature, normalises every payload into one canonical schema, and forwards with ordering, retries and replay. Raw bytes hit Postgres before anything tries to parse them, so a payload we can't understand is still a payload we didn't lose. An unrecognised status becomes unknown — never a guess.

Go Postgres TypeScript · statushub site →

The system that failed cannot be the system that detects the failure. ReconSync watches both legs of a transfer and fires a signed advisory reversal webhook before the regulatory window closes. It checks its own blind spots first: if its ingest had a gap, a missing credit proves nothing.

Go Postgres TypeScript · reconsync site →

Compliance rules written, tested and approved by the compliance officer — no engineer, no pull request, no deploy. Every verdict cites the regulation it implements and carries a message a customer can actually read. Division isn't in the rule grammar: a decision made six months ago has to reproduce exactly.

Python Django Postgres · complylayer site →

A dispute-filing interface for your customers and an SLA-tracked, immutably audited case system for compliance — without building a ticketing product. The clock cannot be paused, because a pausable clock is an abusable one; the alert fires before the breach, not after; and there is no code path to a payment, enforced by a call-graph test rather than by convention.

Python Django Postgres Redis · disputeshield site →

Eight products for the Nigerian market, none of them fintech. Six are cross-platform from one codebase, with functional parity as a hard requirement rather than an aspiration — all six are under way. Two are native iOS, by decision, each with the case for going native written down before the code; both are built as far as a simulator reaches.

Almost every load in Nigerian road freight is agreed on WhatsApp. Backhaul does not try to replace that — it lets a shipper type the two phone numbers they have been messaging and track the truck from there. Tracking is the wedge; matching is the business, and the marketplace is worth nothing until the tracking has earned somebody's trust.

The engineering is in the parts that must not stop: a native capture loop that keeps recording when the network goes, because stopping loses precisely the stretch of road nobody can account for afterwards; a delivery a driver can photograph, sign and seal at a market gate with no signal at all, because the alternative is a driver who finished the run and is not paid. Nothing that is an estimate is ever rendered as a measurement — the arrival window refuses outright rather than guessing, and says what would fix it.

TypeScript React Native Kotlin Swift C#/.NET 9 Postgres — one domain package, four faces, and a parity suite holding the C# server to it.

A Nigerian primary health record is a paper card, and the card stays where it was written. The hard problem is not the record; it is merging two records that were both edited while neither could see the other — two nurses on two tablets, offline for a week, both updating the same child. A last-writer-wins system silently destroys clinical data there, and here silent data loss is not a bug, it is a patient harm. Vitals treats observations as immutable facts that merge by union, never by overwrite; five merge invariants are property-tested over generated multi-device worlds, and the .NET replica runs the same merge in C#, held to the Dart by a 200-world parity fixture that caught the first real defect the same night.

Nothing clinical is computed. A pulse is shown beside the published range and marked outside range by a comparison, never named. The antenatal danger signs are ten questions a nurse answers, each one, and nothing sums them — a test greps the domain for score, risk, triage so a future one fails before it is a regulated device. A pack is on the list, not on the list, or the list cannot say, and no language it speaks has the fourth word. The patient hands the record over on an animated QR built from a grant they chose — which sections, to whom, until when — and a fact outside the grant is never in the bytes. Every open of a record is a fact the patient sees on their own phone.

Dart Flutter C#/.NET 9 Postgres ChaCha20-Poly1305 Ed25519 — glass over a gradient mesh with a solid twin for a three-year-old tablet; five patient-face languages held complete by a gate; a domain that imports nothing; nine build gates, each broken on purpose and watched to fire; a signed audit export a supervisor verifies with nothing but Python. Built in one night to the edge of its hardware gates: mixed Android↔iOS transfer, the reference tablet, and a clinician reading every screen.

Community safety and emergency alerting, and the only product in this portfolio where a design error causes direct physical harm: a false alarm can start a mob, and a "suspicious person" report can get somebody killed. So the rules were written before the code, and they are the product. Alerting your own circle is a right; alarming strangers is a privilege. The personal path — the panic action, the safe-arrival journey that escalates even if the phone dies — is fast and unmetered because it reaches people who already trust you. The public path is earned: a report is visible to 500 m and widens only with independent corroboration, computed by a pure function that is property-tested over generated worlds so that no single account, and no set of accounts sharing an independence signal, can carry an unverified report beyond 500 m.

Nothing about a person, ever — no names, no photographs, no plates, no suspicious person category, and a free-text screen that fails closed. No engagement — no counts, no badges, no analytics SDK. The server cannot read a location: alert and journey positions leave the phone sealed to the circle's keys, and a test hands the server everything it holds and proves it cannot open one. There is no red in the palette and no danger token, because a safety app that shouts manufactures fear.

TypeScript React Native C#/.NET 9 Postgres X25519 XChaCha20-Poly1305 — a domain that imports nothing, a C# replica held to it by a 200-world fixture, a copy gate that bans the words that would cross the line, and eight gates each broken on purpose and watched to fire. Started the same day as Vitals; what it waits on is a handset with a stopwatch, an outside reading of the abuse model, and thirty days in one city with zero harm.

A Nigerian household disputing a bill has nothing to dispute it with: no reading history, no record of how long the power was actually on, no document anyone is obliged to read. Grid records both, values the gap between the service band you pay for and the hours you got, and assembles it into a pack a distribution company and a regulator will accept.

No backend at all in v1. Everything a household needs to act — OCR, supply inference, the arithmetic, the PDF — runs on the phone, because the people who need it most are the ones whose data ran out.

Dart Flutter Kotlin Swift Go Postgres SQLite/Drift

Naira notes have no tactile marking. A blind Nigerian handling cash is trusting the other party, every time — and since the 2022 redesign there are eleven visually distinct notes carrying eight values. Every currency reader on the market covers the dollar, euro, pound, rupee and yen. None covers the naira.

Tender is native Swift and iOS only, and the reason is written down before the code: its user never looks at the screen, so the accessibility layer is not a feature of the interface — it is the interface — and that layer is the platform's own. Point the camera; the app says which note, through VoiceOver, and pulses it through the haptic engine in a pattern different for every value, so the answer lands in a market too loud to hear a phone. It names the denomination and never whether the note is genuine; a word-list gate keeps that sentence out of the app, permanently.

Swift 6 SwiftUI Core ML Core Haptics AVFoundation — a domain package that imports nothing, not even Foundation; Xcode's accessibility audit on every screen at two text sizes; twelve build gates, each broken on purpose and watched to fire. No backend, and a gate that fails on any network path in the source.

It stops at a different wall from the other two, and a better one: a week of photographing eleven banknotes, which is the one gate in this portfolio that waits on nobody but me.

A Lagos tenant pays two years' rent in advance plus a caution fee, and two years later argues about a cracked tile that was cracked on move-in day — with nothing to argue it with. Snag is the record made on the day it can still be made honestly: walk the flat room by room, photograph what is wrong and what is fine, seal it. The evidence is the wedge, not the dispute. The report is worth making for one tenant with no landlord on the other side.

Every photograph is hashed the moment it is taken and stripped of everything but the picture. The report is sealed with a key that never leaves the phone — the Secure Enclave where there is one — and the sealed bundle carries the public key, so any phone with Snag, or a 200-line Python script written from the format document alone, says unaltered since signing or altered, and nothing in between. The landlord counter-signs on the tenant's phone; a move-out walk shows the move-in photograph beside the shutter and says what changed; a scan added months later is a second signature beside the first, touching nothing the first one signed. It says evidence, never proof, on its own last page, and a word-list gate keeps the stronger word out of every language it speaks — five of them, chosen in the app.

Swift 6 SwiftUI CryptoKit ARKit RoomPlan ActivityKit — a domain package that imports nothing, a canonical byte encoding asserted by a checked-in fixture, a verifier proved against every flipped byte of every file, and two verifiers that must agree. Ten build gates, each broken on purpose and watched to fire. No backend, by decision, and nothing sent — the one exception, the tenant's own iCloud, is opt-in and named in an ADR.

What it waits on is a phone in a hand: the measured tier is ARKit and the scanned tier is LiDAR, both built and proved with a fixture room where the simulator has no sensor, and a tape measure in a real room is the gate.

The cross-platform six stop at the same wall, and it is the honest one: a device day on a Transsion handset whose power management is undocumented, and a native speaker for the Hausa, Yorùbá and Igbo. Roughly 2,500 translated keys between them, written by somebody who speaks none of the three. Automated checks prove every string on every screen goes through the table; nothing proves one is right. Both projects list that as a release blocker rather than a nice-to-have.

Every one of the eight is documented the same way — the problem, how it works, each layer, the correctness notes, what is open and why — so a reader who has read one knows where to look in the next.

Where each one stops, and why →

Contract and in-house, across Nigerian and US teams.

Languages · TypeScript · JavaScript · Go · C# · Python · Dart · Kotlin · Swift · SQL

Frontend · React · Next.js · Vue · Tailwind

Mobile · React Native · Flutter · Swift / SwiftUI · Kotlin

Backend · .NET · Go · Django · Node / Express

Data · Postgres · SQL Server · MongoDB · Redis

Infrastructure · Docker · Kubernetes · Helm · Terraform · GitHub Actions

Certified · ISO/IEC 27001:2022 — Information Security Management Systems (ISMS) Foundation (SandBP, Aug 2026)

I write things down before I build them. Every project above carries a set of architecture decision records explaining not just what was chosen but what was rejected and why — because the reasoning is the part that's expensive to reconstruct, and the part that's gone once the person who had it leaves.

I also try to make the failure modes explicit. A system that says unknown when it doesn't know is more useful than one that guesses confidently, and most of the interesting work is in deciding what a service will refuse to do.

The same applies to what isn't finished. Each project's README says where it stopped and what would actually close it — a handset, a translator, a developer account — rather than leaving a reader to guess whether something was hard or just never got done. A blocker that needs a person is not the same as a blocker that needs an afternoon, and writing that down is cheaper than the conversation it saves.

That is also why the ISO 27001 work matters to me rather than sitting on a shelf. The standard is largely about being able to show what happened — access control, audit logging, data classification, evidence retention — which is the same problem the hash-chained audit trails and row-level tenant isolation in these projects exist to solve.

Open to backend and full-stack work — and always happy to talk about fintech infrastructure.