// hello, world
I'm Harry Kaonis.
I build things for the web & mobile.
Full-stack engineer. AI agents, React and React Native apps, Node backends, and the infrastructure under them. Still caffeine-powered.
// about
Who's behind the keyboard?
Senior full-stack engineer with 7+ years shipping React web apps, dashboards, and React Native apps for the App Store and Google Play. On my own time: a Greek EV site built in a night, a multi-site Wake-on-LAN system, an accessibility app for the Athens Metro, and the infrastructure that keeps them running. I dream in async/await and I automate anything I have to do twice.
AI agents
Claude-based agents and tool use, retrieval pipelines, content generation at scale. Agents that do one workflow well, with a human on the approve button.
Web & mobile
React and Next.js for web apps and dashboards, React Native with Expo for iOS and Android, TypeScript everywhere. Accessibility is a feature, not a ticket.
Backend & data
Node.js, Express, PostgreSQL, SQLite, WebSockets, public APIs and daily data pipelines. My debugger of choice is still console.log. (It has failed me.)
Infrastructure
Docker, Traefik, nginx, Cloudflare, Hetzner, Tailscale, GitHub Actions. Everything as code, with runbooks, backups and monitoring. Third time's the script.
// projects
Things I've shipped (that didn't crash… much)
A curated selection of my work. Some useful, some educational, all lovingly over-engineered.
Greek electric-vehicle site: charging map, price comparison, subsidy calculator and buying guides. 600+ generated pages, a public API and daily data pipelines. Built and launched in a single night, then extended daily.
Wake and manage machines across several networks from one phone. A React Native app talks to a command-and-control backend that aggregates per-LAN node agents over WebSockets. Because why walk to your PC when you can wake it from the couch?
Accessibility information for the Athens Metro, for people with mobility needs: interactive network map, per-station elevator and escalator details, outage notifications, dark mode. iOS, Android and web from one codebase.
All my infrastructure in one repo: a Hetzner VPS, a Mac mini homelab and a Synology NAS. Docker services behind Traefik and nginx, Cloudflare DNS and tunnels, Tailscale mesh, nightly encrypted backups, monitoring, and runbooks so any part can be rebuilt from scratch.
Small games built end to end. Big Rush: a Unity 2D platformer with seven levels, co-op and LAN multiplayer. Volt Run: a browser 3D endless highway driver with procedural traffic and an original Blender car. Crater Club: a browser 3D artillery duel with destructible terrain.
A private sci-fi lore universe project with factions, codex entries, timeline content, and newsletter ops, published at ultimagnus.com.
This very website. Yes, I'm listing the site you're looking at as a project. It's called recursion, look it up. 😎
// contact
Let's connect
Hire me for an AI Agent Sprint, bring me a React, React Native or backend problem, or just talk shop. Email gets the fastest reply.