Emailamosmn4@gmail.com Phone+254745600377
Open to new projects
Amos Nyamai.Software Engineer

Software EngineerNairobi · Open to projects

I turn ideas into software people rely on.

I design, build, test, deploy, secure and scale production systems. Payroll for 200+ employees, a POS in 10+ shops, and products of my own like PhotoDrop and ErrandGo.

View my workHow I engineerWhatsApp
200+employees on payroll I led
10+shops on my POS
10kphoto load tests passed
Tafity SmartPOS
Tafity SmartPOS10+ shops
Live products · 14See all work ↗
PhotoDrop
PhotoDropLive
 SmartPOS
SmartPOS10+ shops
 HR & Payroll Platform
HR & Payroll Platform200+ staff
 Receipt Intelligence
Receipt Intelligence400+ receipts
 UMOMS Chama
UMOMS ChamaLive
 Recruitment ATS
Recruitment ATSLive
 Kazi-chapchap
Kazi-chapchapLive
 AIMS
AIMSLive
 RadaTrack
RadaTrackLive
 Prepaid Water Vending
Prepaid Water Vending50+ meters
 Krestworks Platform
Krestworks PlatformLive
 Amsol Jobs
Amsol JobsLive
 Hospital Rota
Hospital RotaLive
 Trinity Workforce Platform
Trinity Workforce PlatformLive
In production

Running today, used every day.

Systems I built that businesses and people depend on right now. Pick one to bring it forward.

See all workRead the case studies
HR & Payroll Platform
See HR & Payroll Platform200+ employees
SmartPOS
Visit SmartPOS ↗10+ shops
Receipt Intelligence
Visit Receipt Intelligence ↗400+ receipts
Prepaid Water Vending
See Prepaid Water Vending50+ meters
PhotoDrop
Visit PhotoDrop ↗10k-photo events
Selected work

Six systems, from first idea to daily use.

HR & Payroll Platform HR & Payroll Platform on a phone
01 / 06
Amsol Africa

HR & Payroll Platform

Payroll, leave and attendance for many businesses in one system, calculated the Kenyan way.

Outcome
200+ employees on payroll
Test
100 feature test files on payroll, roles and data scoping
Secure
Two-factor login, audit trail, custom role builder
Stack
Laravel, MySQL, Reverb, Cloudflare
Read case study Screenshots · login required
PhotoDrop PhotoDrop on a phone
02 / 06
Stawi Social Lab · Product I started · Idea shared with collaborators

PhotoDrop

Event photos in guests' hands the same day. Scan a QR code, see your photos, add your own, download them all.

Perform
Load-tested with 10,000-photo uploads and 1,000 live viewers
Build
Direct-to-S3 uploads, separate workers for photos, video and zips
Stack
Node, TypeScript, PostgreSQL, Redis, S3
Read case study Visit site ↗
Prepaid Water Vending
03 / 06
Amsol Africa

Prepaid Water Vending

Pay by M-Pesa, get your water token by SMS in seconds.

Outcome
50+ meters vended since January 2026
Deploy
GitHub Actions to AWS EC2
Reliable
Failed vends retry with exponential backoff
Stack
Django, Celery, PostgreSQL, React, Daraja
Read case study Screenshots · login required
Tafity Product Suite Tafity Product Suite on a phone
04 / 06
Tafity

Tafity Product Suite

Three SaaS products under one brand: receipts read by AI, a point of sale for shops, and chama and SACCO management.

Outcome
10+ shops on SmartPOS, 400+ receipts processed
Build
Separate M-Pesa ledgers for platform billing and each shop's till
Also
SmartPOS runs white-labelled as Krestworks POS
Stack
PHP, Laravel, MySQL, Daraja, Gemini
Read case study Visit site ↗
05 / 06
Own product · Product I started · Idea shared with collaborators

ErrandGo

Errands and deliveries done by people nearby, paid safely by M-Pesa.

Test
227 automated tests, including slow-query checks
Secure
OTP login, IDs that can't be guessed, masked phone numbers
Stack
Laravel, React Native, TypeScript
Read case study In development
06 / 06
Krestworks

ISMS Station Management

One system for a whole service station, across every branch.

Secure
Token rotation with reuse detection, lockout, new-IP alerts
Test
26 test files, including tenant isolation
Stack
Node, Prisma, React, Flutter
Read case study Staging
All 39 projects ↓
Practice

From the first conversation to years of running.

The same eight stages on every project, from the first conversation to years of running. Each one lists the practices I use and a project where you can see them.

  1. 01 Idea Start with the problem, not the code. Seen in PhotoDrop, ErrandGo
  2. 02 Design Settle the hard parts on paper first. Seen in PhotoDrop, Prepaid Water Vending
  3. 03 Build Code the next engineer can pick up and own. Seen in HR & Payroll Platform, SmartPOS
  4. 04 Test Money, permissions and data get tested first. Seen in ErrandGo, HR & Payroll Platform, ISMS Station Management
  5. 05 Deploy Releases should be boring, on purpose. Seen in Prepaid Water Vending, Kazi-chapchap, PhotoDrop
  6. 06 Secure Designed in from the start, then checked. Seen in ISMS Station Management, MtaaLex Platform, HR & Payroll Platform
  7. 07 Scale Measured under load, then tuned. Seen in PhotoDrop, ISMS Station Management
  8. 08 Maintain I stay after launch. Seen in HR & Payroll Platform, SmartPOS, Prepaid Water Vending
How I engineer, in detail
All projects

Everything I've built.

Products I started, ventures I engineer for, systems for organisations, and websites. Public sites open directly. Systems behind a login show screenshots.

SmartPOS

Tafity

Multi-shop point of sale with M-Pesa, VAT receipts and printing

Live Visit ↗

AIMS

Amsol Africa

Company ERP: CRM, finance, projects, HR and documents

Live · login Screenshots

RadaTrack

US care provider

Care documentation and compliance for adult family homes

Live · login Screenshots
LiveStagingIn developmentPrototypeOffline
About

I'm Amos, a software engineer in Nairobi. I build things people use every day, and I stay to keep them running.

At Amsol Africa and Krestworks I'm the lead backend and AI engineer, working with a team of developers and non-technical colleagues. On my other projects I'm the engineer from start to finish, working directly with clients and with friends who bring ideas. PhotoDrop, ErrandGo and FixMate all started that way.

Most of my work connects software to the real world: M-Pesa, KRA receipts, Kenyan payroll law, biometric clocks, prepaid water meters and receipt printers. Before engineering full time I led AIESEC Chuka as chapter president. That's where I learned to run projects and people.

  • Own the whole lifecycleFrom the first conversation to years of maintenance.
  • Measure, don't guessLoad tests and numbers before opinions.
  • Write it downDocs, runbooks and setup scripts anyone can follow.
  • Stay after launchSoftware changes after it ships. I change with it.
GitHub ↗
Experience

Where I've built.

An employer, the ventures I engineer for, and the roles that taught me to lead.

  • Sep 2025 – NowNairobi

    Lead Backend Engineer & AI

    Amsol Africa
    • Lead backend and AI engineer in a team of developers and non-technical colleagues
    • HR and payroll platform used for 200+ employees
    • Prepaid water vending: M-Pesa to meter token to SMS, deployed on AWS
    • Company ERP, hospital rota, recruitment and marketplace systems
    Laravel · Django · NestJS · React · AWS · Cloudflare
    HR & Payroll platform
    HR & Payroll platform
  • OngoingKrestworks

    Lead Backend Engineer & AI

    Krestworks
    • Lead backend and AI engineer in a mixed team
    • ISMS, a service-station ERP with a documented security review
    • The Krestworks platform, AI tools hub and white-label POS
    Node · Prisma · React · Flutter · PHP
    krestworks.com
    krestworks.com
  • OngoingTafity

    Software Engineer

    Tafity
    • SmartPOS, running in 10+ shops
    • Receipt Intelligence, 400+ receipts read by AI
    • UMOMS, chama and SACCO management with M-Pesa
    PHP · Laravel · Daraja · Gemini
    Tafity SmartPOS
    Tafity SmartPOS
  • 2025MtaaLex

    Software Engineer

    MtaaLex Solutions
    • Legal-tech platform with client portal, shop, trainings and seven AI legal tools
    • Data-protection compliance built in: consent, retention and automatic deletion
    PHP · OpenAI · M-Pesa · Tailwind
    mtaalexsolutions.co.ke
  • 2025 – NowPart time

    Computer Science & ICT Tutor

    Raena Learning Center
    • IGCSE and A-Level computer science for 30+ students
    raenalearning.org
    raenalearning.org
  • Jun – Dec 2024

    IT Specialist & Web Developer

    Image First Ltd
    • E-commerce store and client portal
    • Firewall and network security
    imagefirst.shop
    imagefirst.shop
  • 2021 – 2025

    Chapter President, Director of Finance & Legal

    AIESEC Chuka
    • Led the chapter as president in 2023–24
    • Project manager for the Zinduka Legacy Project
    AIESEC Chuka
Writing

Notes from the work.

Software engineering and AI, written from real projects.

Performance

Load-testing PhotoDrop to 10,000 photos

How we broke the system on purpose, and what we changed.

Coming soon
Payments

M-Pesa callbacks that never charge twice

Idempotency, reconciliation and what to do when Safaricom retries.

Coming soon
Domain

Kenyan payroll in code

PAYE bands, NSSF tiers, SHIF and the Housing Levy, tested.

Coming soon
Contact

Have an idea or a system to build?

Tell me what you need. I'll reply within a day with questions, a rough approach, or a time to talk.

Phone+254745600377
Based inNairobi, Kenya · working worldwide
What do you need?