newton.dev

Senior full stack engineer

This is your engineer
Newton M.

I build software where operations actually happen—fleet hubs, corporate transport, retail floors, and storefronts. I own the arc from messy real-world workflows to schemas, APIs, and interfaces people use every day.

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Nairobi, Kenya · Mango Season Labs

Senior roles · Remote OK
NM

Founder & Lead Engineer

Newton M. Mathenge

Mango Season Labs

Owns products end-to-end · ships what teams run every day

AI-assisted developmentAutomated quality checksQuality gates in CIHands-on mentoring
Shuttle trips / month
10k+
Shuttle trips / month
Sideways · UNON production
Bookings / month
7k+
Bookings / month
Shuttle & taxi · Sideways platform
Years in production
4+
Years in production
Full-stack ownership
Devs mentored
50+
Devs mentored
TechCamp Kenya
LogisticsFintechERPCommerceCorporate transport
Stack
.NETNode.jsPostgreSQLNext.jsExpo

Speciality

My specialities

Product ownership meets senior engineering—I scope, architect, ship, and iterate on systems that run real businesses.

Operations platforms

Employer hubs, fleet, HR, finance, and mobile field apps—systems that run the business, not slide decks.

Integration-heavy backends

Dispatch, payments, SMS, webhooks, and third-party APIs—PostgreSQL, Redis, queues, and observability baked in.

Mobile + web products

React, Next.js, and React Native (Expo)—contract-first APIs with UIs that match how people actually work.

AI-assisted engineering

AI-assisted workflows with human review, automated checks, and merge discipline—nothing ships unverified.

Partners & teams

Built with operators I trust

  • Sideways
    Corporate transport · SIMS · shuttle & taxi
  • UNON
    Staff shuttle · 10k+ trips / month
  • Ujuzi Code
    Lead architect · contract delivery
  • Mango Season Labs
    Founder · product studio
  • KCB Bank
    Agency banking · .NET integrations
  • Equity Bank
    Agency banking · field workflows
  • TechCamp Kenya
    Technical mentor · 50+ devs
  • Turing
    Remote engineering · technical evaluation

Transport ops, agency banking, and cohort mentoring—shipped together, not logo-slapped.

Selected work

A few projects I've shipped

Not the full list—just a sample of production software across operations, transport, commerce, and product-facing web apps. Happy to walk through more.

SIMSFleet · HR · Finance · Mobile

Operations platform

SIMS

Founder & Lead · Mango Season Labs

Sideways Information Management System—employer hub plus Expo driver app for jobs, vendor services, fleet, HR, finance, and cross-org ticketing.

.NET 10PostgreSQLRabbitMQRedis
Sideways Shuttle10k+ trips / month

Corporate transport

Sideways Shuttle

Lead Architect · Ujuzi Code

UN-context staff shuttle—booking to dispatch, passenger apps, QR onboard/offboard, client portals. 10,000+ trips per month.

FastifyPrismaPostgreSQLRedis
Running Coach318+ activities tracked

Sports / SaaS

Running Coach

Lead Architect · Ujuzi Code

Coach Dedan platform—per-race form builder, Strava webhooks, registration flows, and analytics for cohort training.

NestJSStrava APINext.jsWebhooks
UzaXMulti-tenant shops

Commerce platform

UzaX

Founder & Lead · Mango Season Labs

Shop + storefront platform with bespoke backends, social posting engine, and live tenants including hhourssop and YSK.

NestJSPrismaBullMQNext.js
Tosha Cityadmin.toshacity.co.ke

Retail ERP

Tosha City

Founder & Lead · Mango Season Labs

Butchery management—stock sessions, sales, wastage with evidence, M-Pesa payments, activity logs, and reporting.

NestJSTypeORMPostgreSQLNext.js
LakeTownKitchen · Retail · Prep

Restaurant / production

LakeTown

Founder & Lead · Mango Season Labs

Pork House ops—kitchen, table orders, production flow, meat counter and prepared plates in one product loop.

NestJSTypeORMPostgreSQLNext.js
JimcabAuto dispatch

Corporate taxi

Jimcab

Lead Architect · Ujuzi Code

Zone-based dispatch, queued drivers, automated SMS, and admin for corporate taxi—same family as Sideways.

FastifyRedisQueuesPostgreSQL
Ask about other work

Services

My other services

What I bring as a founder-engineer—whether building in-house or joining your team on contract.

◆

Product engineering

End-to-end delivery for ops-heavy products—from discovery through production deploy.

◆

System architecture

Modular backends, queue-backed workflows, and data models built for scale and clarity.

◆

Legacy & greenfield

Onboard into existing .NET or Node codebases—or architect new stacks without over-engineering.

◆

Integrations

Banking, dispatch, Strava, OAuth, SMS—production integrations with audit and retry discipline.

◆

Mobile + admin UIs

Expo driver apps, Next.js admin dashboards, and API-driven surfaces aligned to one contract.

◆

Technical leadership

Docs, PR review, mentoring—50+ developers through TechCamp Kenya; team enablement, not silos.

◆

AI-assisted development

AI tools for speed, human review for correctness—regression checks and quality gates woven into daily delivery.

About

Founder who ships

“I don’t hand off specs—I own the product from messy real-world ops to production.”

I ran Mango Season Labs—a studio where we design, build, test, deploy, and train teams on bespoke software for businesses. The point is practical tools that streamline day-to-day work: employer hubs and mobile apps for fleet operators, retail and POS on busy shop floors, commerce and booking flows where downtime actually costs money. I also architect products for Ujuzi Code on contract when a team needs someone who owns the arc from messy ops to production, not just the build phase.

I mentor at TechCamp Kenya (50+ developers)—MERN fundamentals through to modern product engineering—and I care that what we ship is documented, observable, and still understandable six months later.

Technical ecosystem

Backend

Node.js (NestJS, Fastify), C# / .NET, REST, BullMQ, WebSockets

Frontend

React, Next.js App Router, React Native (Expo)

Data

PostgreSQL, Prisma, TypeORM, EF Core

Platform

Docker, Linux, GitHub Actions, Redis, RabbitMQ, Grafana

AI & quality

AI-assisted dev, automated review, CI checks, structured PR review

About me

My work process

From messy ops conversations to software your team can run without you in the room.

01

Discover

Map the real workflow—who acts, what breaks, what must not fail.

02

Design

Schema, module boundaries, and API contracts before pixels.

03

Build

Ship backends, workers, and interfaces in tight iteration loops.

04

Deploy

Docker, CI, and production paths the team can run without heroics.

05

Observe

Logs, metrics, audit trails—honest visibility into what shipped.

06

Iterate

Improve from live usage; the product earns trust over months, not demos.

Contact

Let’s build something real

Available for senior engineering roles, contract architecture, and founder-led product builds. CV and portfolio available on request.

dev.newton.mathenge@gmail.com
+254 790 656 196Nairobi, Kenya · Remote-friendly
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