Joel Aduma

Nairobi, Kenya — mobile & security engineer

I build the parts of a banking app you trust without thinking about it.

5+ years shipping React Native apps for regulated fintech — biometric authentication, offline-first sync, and SCA-compliant architecture — plus AI-integrated products for teams across three continents.

Download résumé

Diamond Trust Bank, Turing, Zapi.ai, and remote teams across Africa, Europe & Hong Kong.

Mobile work

The apps I’ve spent the most care on — where the interesting problems are offline state, biometrics, and keeping a banking-grade experience feeling fast.

DTB m247

Flagship mobile banking app

Senior React Native developer on Diamond Trust Bank's flagship app. Mapped Java SpringBoot microservices into offline-first state, architected modular hooks with Zustand, and shipped SCA-compliant biometric MFA.

Security rating 78% → 95%View app

KejaHunt

House-hunting, built offline-first

A React Native app for finding rentals in Kenya without relying on a constant connection — local-first search and sync patterns carried over from banking work.

Personal product, solo-builtView app

Reduce My Carbon

Carbon calculator with M-PESA payouts

Architected the MVP for a carbon-emission calculator: mobile app plus API, M-PESA integration for offset payments, and biometric authentication for identity.

Mobile app + API, MVP to launchView app

Also built

Africa Mining Legislation Atlas — Built the entire frontend for the African Legal Support Facility (African Development Bank) — data-dense geographic mapping and legislation dashboards.2021–2022 Africa Arbitration Atlas — Front-end development for a research platform tracking arbitration law across the continent.2021 Zapi.ai — Modular React + TypeScript components for an AI API marketplace, including live-preview SDK documentation. Cut onboarding friction by 40%.2022–2023

Experience

Turing

Jan 2026 – Apr 2026

Full-Stack Software Engineer — Generalist, AI Projects

Nairobi, Kenya (Contract)

Selected for a global contractor role on Turing's Generalist track, working across ambiguous problem spaces and unfamiliar codebases.
Integrated LLM capabilities into applications — prompt-driven workflows, data transformation, and intelligent feature layers.
Collaborated with globally distributed teams on system design, code review, and iterative delivery.

Diamond Trust Bank

Jul 2023 – Present

Senior React Native Developer

Nairobi, Kenya

Mapped Java SpringBoot microservice APIs to React Native state, ensuring offline-first sync across the flagship banking app.
Architected modular components and custom hooks in TypeScript and Zustand, cutting code duplication by 30%.
Integrated SCA-compliant biometric MFA, raising the internal security audit score from 78% to 95%.
Automated build and distribution via Firebase App Distribution and TestFlight, cutting deployment time by 40%.
Mentored two junior developers on mobile architecture, Git workflow, and performance profiling.
Drove performance work that cut app startup time by 30% and held crash-free sessions above 99.5%.

Amband Ltd

Sep 2022 – Jun 2023

Full Stack Developer

Nairobi, Kenya

Built high-throughput Laravel APIs tuned for low-bandwidth environments behind Android utility apps.
Shipped the API for a waste-collection system used at Kakuma Refugee Camp, in partnership with DanChurch Aid Kenya.

Zummit Africa

Nov 2022 – Mar 2023

Frontend Developer

Lagos, Nigeria (Remote)

Built modular React + TypeScript components for Zapi.ai, an AI API marketplace.
Improved onboarding by 40% by integrating AI SDK documentation interfaces for remote teams.
Raised UI rendering efficiency by 25% through memoization and React performance profiling.

Farwell Innovations Ltd

Mar 2021 – Jul 2022

Software Developer

Nairobi, Kenya

Built corporate e-learning platforms for enterprise clients using Laravel and React Native.
Implemented reusable UI components and Firebase Cloud Messaging push notifications.
Built React dashboards for learning analytics, 20% faster to load than the previous version.

Save the Children International

Mar 2020 – May 2020

IT Intern

Nairobi, Kenya

Updated and validated the internal Snipe-IT asset management system.
Automated reporting scripts, removing redundant asset entries and improving data accuracy.

Skills

Mobile & Frontend

React NativeTypeScriptReactNext.jsZustandReact NavigationContext APIExpoGraphQLREST APIs

Security & Authentication

Biometric Auth (Face ID / Touch ID)SCAMFAOAuth2JWTAWS Liveness Detection

Backend & Integration

Node.js / ExpressLaravel / PHPMySQLMongoDB

Cloud & Delivery

AWS AmplifyFirebase FirestoreFirebase Cloud MessagingS3TestFlightFirebase Analytics

Testing & Collaboration

JestPlaywrightAzure DevOpsJiraAgile / Scrum

About

I'm a senior React Native engineer based in Nairobi, currently building the mobile banking app at Diamond Trust Bank — the kind of app where a dropped frame or a biometric edge case is a production incident, not a bug ticket.

Most of my last five years have gone into that discipline: bridging device hardware and biometrics with TypeScript mobile architecture, keeping apps usable offline, and passing security audits rather than just clearing them. I've done the same thing for a carbon-offset app with M-PESA payouts and a personal house-hunting app, and shipped the frontend for legal and civic platforms used across Africa.

I've worked with teams in Nairobi, Lagos, Hong Kong, and fully remote AI teams through Turing — different codebases, same habit of asking what happens when the network drops or the fingerprint sensor fails.

Currently open to senior React Native and mobile architecture roles.

Let’s build something that has to work.

caesaragen@gmail.com