Engineering expertise

Mobile engineering

React Native & Expo mobile engineering

I build mobile products as complete systems rather than isolated screens: app architecture, navigation, secure authentication, native device capabilities, API integration, local persistence, analytics, testing, release, and the backend workflows required to support the product.

What this looks like in practice

  • Voice recording, playback, reminders, goals, biometrics, secure token storage, and store release workflows in JournPad.
  • Invoice-linked rent payment and reconciliation workflows in RentPayor.
  • Driver, cargo, location, reservation, and payment operations in Macsim Cargo.
  • Wardrobe, image-analysis, location, OAuth, and recommendation workflows in AI Stylist.

Core technologies

React NativeExpoTypeScriptExpo RouterEAS BuildExpo UpdatesSQLiteSecureStoreAsyncStorageiOSAndroid

Project evidence

Products that demonstrate this capability

Each project below links to a deeper case study covering product scope, engineering ownership, supporting systems, and production evidence.

SaaS · Case study

JournPad: Voice Journal

Voice-first journaling app that preserves the original recording, transcribes spoken entries, and uses AI to generate useful titles, summaries, and categories. Entries can be searched and revisited by date, linked to goals, supported by reminders and prompts, and protected with account, deletion, and optional biometric controls.

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Enterprise · Case study

RentPayor

Rent collection and reconciliation software for landlords and property managers. RentPayor connects iOS and Android apps with a web management dashboard for landlords and property managers. It handles properties, leases, rent invoicing, M-Pesa collections, partial payments, automatic reconciliation, receipts, credits and reporting.

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SaaS · Case study

SchoolPey

School-fee billing and collection software with an Android parent experience and web administration dashboards for schools. Manages students, guardians, term invoicing, M-Pesa payments, receipts, balances and reconciliation.

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Enterprise · Case study

Milliol Construction Manager

Android construction-operations application for project progress, work items, procurement, inventory and stock, financial tracking and operational reporting.

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Enterprise · Case study

Macsim Cargo

Cargo and logistics operations platform spanning mobile field workflows and back-office administration. Macsim handles loads, reservations, driver assignments, trip tracking, documents, notifications, fleet operations and finance, with a guarded M-Pesa/Daraja flow for funding a collection-account ledger and paying drivers in full or partial load installments.

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SaaS · Case study

AI Stylist

Mobile wardrobe-management and outfit-recommendation product. Users create wardrobes, upload clothing photos for AI-assisted category, tag, and description analysis, and generate one-time, daily, or weekly outfit suggestions that can use precise local weather; recommendation history is stored locally in SQLite and designed to sync with the cloud.

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Let's build something that lasts

Have a software challenge? Let's turn it into a working product.

Talk directly with the engineer responsible for your project. Joeltech Geek Systems works with businesses and founders in Kenya and across the world.