Senior Full-Stack & Systems Engineer | Fintech & AI Systems

Kiragu Maina • Peerlist

a2ui-free is an open-source, provider-agnostic LLM factory for developers who want to build on free-tier models without hard-wiring a vendor.It exposes a single client interface over roughly 90 free models across OpenRouter, Groq, Google AI Studio, Cloudflare Workers AI and other providers, and a weekly cron probe that exercises every model, records latency and failure modes, and prunes dead endpoints automatically, so the catalog stays honest without manual upkeep.Key engineering features:- One factory interface, many providers: swap models by name, not by rewriting call sites- Weekly automated liveness probe with per-model latency and error tracking- Capability tags (context window, tool use, JSON mode) so callers can select by need- Zero-cost by design: only free-tier endpoints, with fallbacks when a provider rate-limitsSource and docs: https://github.com/kiragu-maina/a2ui-free

a2ui-free

USSDShield is an open-source Android security application built in Kotlin that prevents shoulder-surfing during M-Pesa USSD payment sessions.Using Android's AccessibilityService, USSDShield detects active system USSD dialogs from Safaricom and M-Pesa and overlays a secure input layer, masking sensitive PIN digits as you type.Key engineering features:- Zero network permission: runs entirely offline, on-device- High-precision dialog overlay matched to Safaricom USSD view hierarchies- Lightweight AccessibilityService lifecycle with no background polling- Open-source Kotlin codebase on GitHubTry it out or inspect the source: https://github.com/kiragu-maina/USSDShield

USSDShield

MyPhotoAI is a proof-first AI headshot and portrait generation engine. I took over the codebase in 2026 and rebuilt it as a production system where clean images and watermarked previews are strictly isolated at the storage level, then grew it a programmatic SEO funnel that now serves 1,898 static pages.What I built:- 4 lane-routed AI providers: Gemini variants, InstantID on Kaggle T4 GPUs, and Flux LoRA on Replicate and RunPod, with zero-dollar failover routing- Server-enforced 402 download gate: clean image URLs are never exposed to client-side DevTools- 3-tier prompt safety recovery ladder with MediaPipe BlazeFace quality scoring- Adaptive Redis spend gate that tracks 7-day median usage and blocks compute spend spikes- 1,898-page programmatic SEO engine built from a 2,158-keyword manifest, served on Cloudflare Pages at near-zero hosting cost, with IndexNow liveness queues and an LLM helpfulness gate on every page- Checkout in 10 local currencies for high-fraud-region conversionStack: React, TypeScript, Express, PostgreSQL, Redis, Gemini, Stripe, Cloudflare Pages, Docker.Case study: https://kiragu.alkenacode.dev

MyPhotoAI

FyberPay is a multi-tenant ISP billing and payments platform where a mobile money payment triggers a change-of-authorization RADIUS packet directly at the network router, so a customer is online seconds after paying.What I built as the sole engineer:- 8 payment rails: M-Pesa STK Push, B2B, reversals, Paystack, KopoKopo, and bank paybills, behind unified API response contracts- 3-layer idempotency: namespaced request interceptors, unique database receipt constraints, and a transactional outbox, so network drops and duplicate webhooks never double-charge or lose a receipt- Per-tenant circuit breakers that separate a customer's wrong PIN from a provider outage- Reconciliation state machine with automated dunning and PDF invoicing- FreeRADIUS and MikroTik integration for hotspot and PPPoE subscriber control- 17 Docker microservices with 75 outbox event listeners, and schema-shape assertions that block container updates on broken migrationsScale: 876 production HTTP endpoints, 263 hand-written SQL migrations, 8,200+ automated tests (the API test suite is 81 percent the size of the production code).Stack: Next.js, NestJS, TypeScript, PostgreSQL, Redis, BullMQ, FreeRADIUS, MikroTik, Docker.Case study: https://kiragu.alkenacode.dev

FyberPay

Developed a reimagined version of the popular Aviator game, featuring four concurrent game sessions. In this game, players can choose from four balloons and place bets on which balloon they believe will pop last. The project involved designing an engaging user interface, implementing real-time game mechanics, and ensuring a seamless betting experience. Features: Four Concurrent Games: Players can choose among four balloons and place a bet for preemptive cashout in four simultaneous game sessions. Betting System: Added functionality for players to place bets on the balloon they think will pop last. Real-time Mechanics: Ensured smooth and real-time game interactions using WebSockets. Engaging UI: Designed an intuitive and attractive user interface to enhance user experience. Technologies Used: Backend: Django, Celery, Celery Beat, Postgres, Redis, asyncio, hmac, hashlib and more python packages.. Frontend: HTML, CSS, JavaScript, PhaserJS Real-time Communication: WebSockets using Django Channels

A Crash Game Reimagined

This react project is a frontend application that provides construction rates and ecommerce service for hardwares

construction rates

A backend API of a dating app, built using NestJS, Prisma, and Docker. The API supports full CRUD operations, database integration, data seeding, and Swagger documentation for easy testing and exploration.

Dating App API with NestJS, Prisma, and Docke

This server provides an endpoint which on call provides a random image generated by stable diffusion based on random gpt-2 text completions. An example of a prompt to gpt-2 could be like, an image of... or a portrait of.. All the models used are thro' an inference api provided by hugging-face. The frontend displays the randomly generated image on generate image

django rest server -- random image generation

This system goes beyond just visualizing truck locations on a map, offering a comprehensive view of your delivery operations. Reduces logic errors in delivery routing. Enables real-time fleet visibility.

Dynamic Delivery Tracking System

A Todo List Application built using modern web technologies and enhanced with Google Sign-In Integration for seamless user authentication.