- Built geospatial backend on Django + PostGIS for a Cyprus real-estate product: parcel data modeling, spatial queries and admin tooling over MultiPolygon (3D) geometries.

- Engineered ETL pipelines parsing Greek cadastral JSON into PostgreSQL — handled nested structures, BIGINT overflow and deduplication via ON CONFLICT, with batch operations instead of row-by-row loops.

- Implemented dynamic parcel filtering in Django admin with bidirectional Leaflet map - widget synchronization; merged and deduplicated three parcel tables into one clean source.

- On the education platform (FastAPI): cut a core /process-question endpoint from ~9s to ~5s using AsyncOpenAI and asyncio.gather for parallel TTS and history persistence.

- Reduced a rules-loading method from N+1 queries to a single batch query, and parallelized audio generation (ThreadPoolExecutor + caching) in a 1,100-line exercise pipeline.

- Integrated OpenAI and ElevenLabs for dynamic exercise generation and speech synthesis; added JWT auth with refresh tokens and file-based chat history.

- Designed and built a Flask + MQTT web control panel for centralized, real-time management of ~50 charging stations: configuration, start/stop, connection status and charge levels.

- Added authentication and role-based access control (admin, operator, technical service).- Implemented an IoT telemetry service ingesting device data over HTTP and WebSocket, storing time series in InfluxDB and visualizing metrics via Grafana dashboards.

- Developed a PyGame/Flask client for on-device LED screens (text, animated banners, QR previews) and managed GPIO-LED indication and ALSA sound notifications via systemd/udev.

- Built declarative network config for automatic Wi-Fi/LTE connectivity with reliable fallback switching between interfaces.

- Delivered 4 web projects end-to-end — from new feature development and API design to maintenance, bug fixing and functional testing.

- Built REST APIs (DRF) enabling integration across multi-platform applications.

- Maintained and enhanced existing production sites, resolving defects and shipping updates throughout the development lifecycle.

- Developed GPS-tracking systems and automated performance-analysis tools for urban and municipal transport.

- Built software for parking terminals.

- Built an internet platform for freelancers, integrating Stripe for payment processing.

- Developed and optimized a platform automating intangible-asset assessment, reducing routine task time for business users.

- Worked in Agile (Scrum/JIRA) with comprehensive PyTest coverage.

- Delivered ~10 web and mobile projects end-to-end: e-commerce platforms, CRM systems, ad-monetization and healthcare applications.

- Engineered robust APIs powering mobile application functionality and integrations.