Simon Njunu Kibiru

Summary

Full Stack Ruby on Rails Engineer with 5+ years delivering production-grade applications for founders and enterprises across Kenya. Specializes in transforming early-stage prototypes into scalable, maintainable systems using the Rails ecosystem — Hotwire, Turbo, Stimulus, PostgreSQL, and cloud-native deployments. Track record of shipping high-impact products: a crowdfunding platform that raised KES 1 million in two weeks, a live workforce SaaS, an inventory management platform for African SMEs, and a contracted O2O campaign system for VIVO Kenya. Comfortable leading small engineering teams, making autonomous technical decisions, and iterating rapidly on founder feedback.

Technical Skills

Languages: Ruby, JavaScript, SQL
Frameworks: Ruby on Rails, Hotwire (Turbo + Stimulus), View Components, Tailwind CSS, RSpec, Vue.js
Databases: PostgreSQL, MySQL, Redis
DevOps & Tools: Docker, Kamal, Git, GitHub Actions, Nginx, Linux, Digital Ocean, AWS S3, Capistrano, Skylight
Integrations: M-Pesa Daraja, Africa's Talking (SMS), Postmark, SendGrid, PesaPal, Stripe, Web Push API, Active Storage
Methodologies: Agile / Scrum, TDD, Rapid Prototyping, Technical Leadership, Code Review

Experience

FlexiGig — Lead Ruby on Rails Developer Nov 2024 – Present | Hybrid

SaaS platform connecting businesses with on-demand gig workers for field activations, data collection, and last-mile execution — View on Play Store

Architected and built the full-stack Rails SaaS powering workforce operations for subscribed enterprise clients and walk-in businesses, including job assignment, worker verification, and real-time performance tracking.
Engineered a custom feature flag system enabling zero-downtime, per-client rollouts of new capabilities without code branching.
Built a secure RESTful API using metaprogramming-based role-behaviour injection, powering the mobile app and reducing duplicate controller logic by ~40%.
Developed an earnings module for the external workforce and a configurable data collection tool for enterprise clients.
Led a team of 3 developers — ran whiteboard architecture sessions, conducted code reviews, managed sprint planning, and drove technical debt triage.

CityRight LLP — Ruby on Rails Developer Aug 2020 – Jun 2024 | Hybrid

Software development and consultancy agency, Nairobi

Led end-to-end development of Agulu Crowdfund (Rails, PostgreSQL, GoodJob) — from architecture and Figma-to-code implementation to deployment. The platform raised KES 1 million+ in its first two weeks post-launch.
Built Biashara360, a multi-tenant inventory management SaaS for African SMEs featuring real-time stock tracking, automated purchase orders, VAT calculations, and reporting. Applied TDD with RSpec throughout, achieving a 20% reduction in production bug rate.
Implemented M-Pesa and PesaPal payment gateway integrations alongside SendGrid transactional email, enabling thousands of transactions and improving user activation.
Established a peer code review culture and Jira-based bug triage workflow; ran weekly Q&A sessions with QA and project managers to document, prioritise, and resolve issues efficiently.
Participated in daily stand-ups and bi-weekly sprint planning sessions, consistently delivering features on time within an Agile/Scrum framework.

Projects

VIVO Kenya — O2O Sales Campaign Platform (Contracted) vivoexclusive.shop

Contracted Rails 8 platform for VIVO Kenya enabling online-to-offline sales campaigns. Admins create QR-code campaigns with public landing pages; VBA field agents verify leads and collect M-Pesa payments via an offline-capable PWA; the admin dashboard streams live order and payment updates via Turbo Streams.

Rails 8 Hotwire PostgreSQL M-Pesa Daraja Africa's Talking PWA / Web Push Docker / Kamal

Biashara360 (Byz360) — Inventory Management SaaS biashara360.com

Smart inventory management platform for African SMEs with real-time stock tracking, automated purchase orders, VAT calculations, and reporting dashboards. Mobile-first design targeting small business owners across Kenya.

Ruby on Rails Tailwind CSS PostgreSQL Stimulus JS M-Pesa

FlexiGig — On-Demand Workforce Platform Play Store

Built the Rails backend and RESTful API powering the FlexiGig mobile app — real-time job notifications, worker verification, location tracking, and earnings management for on-demand field workers across Kenya.

Ruby on Rails RESTful API PostgreSQL GoodJob

Agulu Crowdfund — Community Fundraising Platform

Full-stack crowdfunding platform built with Ruby on Rails, PostgreSQL, and GoodJob for background job processing. Enabled community-based fundraising initiatives — raised KES 1 million+ within two weeks of launch.

Ruby on Rails PostgreSQL GoodJob Mpesa