Marius Mariakinas
info@marius.devFor 12+ years I've been building production IT systems for businesses mostly CMS and ERP style platforms across web, mobile, backend, and DevOps.
I operate as the systems architect - i translate business requirements into technical solutions, making the critical decisions on structure and strategy to ensure the product app is scalable, secure, and maintainable, i look after the full lifecycle from planning to deployment and monitoring, end-to-end.
I collaborate with designers, product/project managers, and other engineers to ship reliable features quickly, adapting to each team's budget and delivery process.
Below are a few client projects I delivered end-to-end as a solo developer that are running in production today. Some are under NDA, so I can't share names or screenshots, but I can walk through the problems, architecture, and outcomes.
Stack
Web
Mobile (iOS & Android)
Server
Client Work
Book Writing Platform
Built a digital storytelling platform that helps users turn life experiences into a professionally formatted memoir through guided prompts, in-app editing/refinement, and automated book layout generation. Also delivered a separate admin app where staff can manage orders, track key metrics, and run day-to-day operations.
AI Learning Platform
Built a web app for learning AI with structured courses, quizzes, and a playground chat experience where users can choose different AI models, send images, generate audio, and experiment hands-on.
EV Charging Platform
Delivered an EV charging marketplace platform: a React Native iOS/Android app for drivers to find hosts offering charging stations, plus a React admin panel for account management and KYC operations. Implemented Stripe payments and shipped a Node.js/Fastify/PostgreSQL backend with real-time WebSocket updates.
Payment Gateway Integrations
Integrated multiple payment providers behind a unified, multi-currency backend service. Built React dashboard panels for real-time monitoring and invested in automated test coverage with Vitest, React Testing Library, and Playwright.
Automation System
Built an automation system that integrates an external AI service for market-trend analysis. Used Node.js Workers to offload CPU-heavy tasks, delivered a React admin dashboard for bot management and performance monitoring, and split the Node.js/Fastify/PostgreSQL backend into two services to better distribute load. Used Redis BullMQ to handle high throughput (30k150k messages) and validated critical flows with Playwright + Vitest.
Government Resources Management
Built a system for government agencies to track contractor costs and delivered services across multiple sectors. Implemented role-based access for three account types, calendar management, controlled account creation, and detailed monthly reporting with filters. Enforced access control with both frontend and backend validation.
Restaurant Management Platform
Built a restaurant operations platform that supports sign-up and day-to-day management of orders, tables, employees, and inventory. Delivered a React web app, a React Native mobile app, and a Node.js/Fastify/PostgreSQL backend with WebSockets for real-time updates and Stripe payments. Also built a customer-facing mobile app for browsing the menu, placing orders, and tracking them in real time.