Currently building Theron|Heraklion, Greece

    Antonis Chalkias

    Software Engineer

    Full-stack and mobile engineer with 3 years shipping production systems for government and enterprise clients, plus 8 years leading teams in the Hellenic Army.

    GitHubLinkedIn

    Profile

    About

    Full-stack engineer, second career after 8 years leading in the Hellenic Army.

    I build production web and mobile products end to end — Next.js and React frontends, Java/Spring Boot, Django and Supabase backends — currently as a software engineer at UniSystems and freelance at Nerion, alongside my own product, Theron.

    Before software, I spent 8 years as an officer in the Hellenic Army, leading a 100+ person unit through logistics planning, risk management, and time-critical decisions — the same systems thinking I now apply to engineering.

    Languages:
    Greek (native), English (C2), Spanish (A1)
    Education:
    MSc Web & Smart Systems, Frederick University (2023–2025)
    antonis.config.ts
     1const antonis = {
     2  role: "Software Engineer",
     3  focus: ["full-stack", "mobile", "AI"],
     4  experience: {
     5    years: 3,
     6    military: 8
     7  },
     8  building: [
     9    "Theron — gym management software"
    10  ]
    11};

    Military Leadership

    8 years as an officer in the Hellenic Army, directing a 100+ person unit.

    MSc, Web & Smart Systems

    Frederick University — thesis on AI food recognition and weight estimation.

    PMP® Prep Completed

    Project Management Professional exam prep completed, certification exam pending.

    3 Years Shipping Production

    Software engineer at UniSystems, freelance at Nerion since June 2023.

    Founder, Theron

    Building gym management software solo, end to end — product, code and deployment.

    AI-Assisted Workflow

    Use Claude Code and agentic tooling daily to move faster without cutting corners.

    Track record

    Experience

    Where I've worked and what I've shipped.

    1. Ongoing

      Theron — gym management software

      Founder & Developer

      Solo-built management platform for gyms and personal trainers (iOS, Android, web): memberships and renewals, client programmes, revenue and retention reporting, and a member app with AI food recognition — architecture, mobile and web development, and deployment end to end.

      • React Native
      • Next.js
      • Supabase
      • Stripe

    2. Sep 2024 – Present

      Secure Web Applications @ UniSystems

      Government & Enterprise

      Building secure, high-availability web applications for government agencies — Next.js and TypeScript on the front, Java and Spring Boot services behind them — translating Figma designs into production UI and shipping a shared internal component library.

      • Next.js
      • TypeScript
      • Java
      • Spring Boot
      • PostgreSQL

    3. Jun 2023 – Present

      Freelance Web Development @ Nerion

      Modern Web Platforms

      Part-time freelance work across Django and Next.js/TypeScript codebases, focused on performance, SEO, and modernizing legacy systems.

      • Django
      • Next.js
      • TypeScript
      • SEO

    4. 2025

      AI Food Recognition & Weight Estimation

      MSc Thesis

      Multi-task deep learning model (ResNet50, PyTorch) for food classification and weight regression, trained on a custom-labeled dataset spanning 47 food categories.

      • PyTorch
      • Computer Vision
      • Kaggle

    Work

    Personal & Freelance Projects

    Things I've built and shipped on my own.

    Founder & solo developerLive

    Theron — gym management software

    Gym and personal-training management software: memberships and renewals, client programmes, revenue and retention reporting, and a member app with AI food-scan macro tracking. Built solo end to end on React Native, Next.js and Supabase, live on the App Store and Google Play.

    • React Native
    • Next.js
    • Supabase
    • TypeScript
    • Stripe
    • OpenAI
    Read the case studytheronapp.com
    Freelance — full-stack developmentLive

    Archon Properties — Real Estate Agency Website

    Bilingual real estate website for a Heraklion, Crete agency — listings, 3D virtual tours, and service pages, built with Next.js for performance and SEO.

    • Next.js
    • Multilingual (i18n)
    • SEO
    • Client Project
    archonproperties.gr

    Toolkit

    Tech Stack

    What I build with day to day.

    Frontend

    • React
    • Next.js
    • TypeScript
    • JavaScript
    • Tailwind CSS
    • SASS

    Backend & data

    • Spring Boot
    • Java
    • Django
    • REST APIs
    • PostgreSQL
    • MySQL
    • Supabase

    Tooling & delivery

    • Docker
    • Git
    • Jira
    • WebStorm
    • VS Code
    • Bash

    AI & machine learning

    • Python
    • PyTorch
    • Computer Vision
    • Agentic Workflows
    • n8n
    • Kaggle

    Other

    • Firebase
    • Google Maps API
    • SEO
    • SSR
    • Vim

    Contact

    Let's talk

    Open to new opportunities and interesting problems.

    Thanks for reading this far.

    © 2026 Antonis Chalkias