Hi, I'm Leonidas Papanastasiou

Experienced software engineer with 6+ years building scalable cloud-native systems, digital-asset and trading platforms, and blockchain systems across banking, finance, energy, and supply chain sectors.

6+ Years Experience

15+ Enterprise Clients

3 Award-Winning Projects

Learn More Download Resume

About

Software Engineer with 6+ years of experience building scalable cloud-native systems, blockchain systems, and digital-asset and trading platforms. Expert in Django/FastAPI/React and Python-based architectures across banking, finance, energy, and supply chain sectors.

Specialized in trading and digital-asset platforms, real-time data pipelines, and low-latency, high-throughput systems. Currently a Consultant - Software Engineer at UpcoMinds, building a regulated digital-asset investment platform for a major Greek bank, after improving the Order Management System of a New York quantitative hedge fund.

Cloud-Native Systems

Scalable architectures serving 5,000+ users

Blockchain Systems

Supply chain transparency solutions

Trading & Digital Assets

Order management & real-time market data

Data Engineering

Real-time analytics pipelines

Education

MSc in Data Science & Information Technologies

National & Kapodistrian University of Athens

Big Data & Artificial Intelligence

BSc in Informatics and Telecommunications

National & Kapodistrian University of Athens

Software Engineering & Algorithms

Top 3 Freshman 2:1 Honors

Experience

UpcoMinds

Consultant - Software Engineer

Jun 2026 - Present Athens, Greece

Current Position

Client: a major Greek bank

Engineered a retail digital-asset investment platform on async FastAPI microservices and PostgreSQL/TimescaleDB

Built the back-office control plane: per-asset trading kill switch, forced liquidations and a bank-wide exposure view

Enforced four-eyes (maker-checker) approvals with Microsoft Entra ID SSO and role-based access per bank team

Integrated core banking fund holds with self-healing end-of-day reconciliation on Azure Container Apps Jobs

Streamed real-time WebSocket market data through Azure Web PubSub into TimescaleDB price candles

Hardened the platform with idempotency keys, circuit breakers, an append-only audit trail and OpenTelemetry tracing

Quantitative Hedge Fund

Consultant - Quantitative Software Engineer

Jun 2025 - Mar 2026 New York, US

Designed scalable internal software solutions aligning quantitative strategies with technical infrastructure

Enhanced Order Management System (OMS), improving execution latency and reliability

Resolved system bottlenecks, boosting application availability in high-volume trading environments

Wings ICT Solutions

Blockchain & Data Engineer

Apr 2023 - May 2025 Athens, Greece

Architected scalable private blockchain systems using Hyperledger Besu and custom Solidity smart contracts

Implemented Flask-based RESTful microservices with 20+ endpoints for blockchain interaction layers

Orchestrated serverless data ingestion, reducing latency by 50% and infrastructure costs by 25%

Evolution Projects+

Full Stack Engineer / Product Manager

Sep 2020 - Apr 2023 Athens, Greece

Delivered Django-based Waste Data Management System with 92% ML forecasting accuracy, adopted by 45+ municipalities

Led award-winning enterprise platform development: ReactJS/FastAPI/PostgreSQL system scaling to 5,000+ users

Built energy complaint portals and real-time geospatial systems handling 2,000+ field tickets

Liquimar Tanker Management Inc.

IT & Network Analyst

Jun 2018 - Apr 2020 Athens, Greece

Maintained enterprise IT systems and implemented firewall/VPN policies for secure network infrastructure

Conducted stress tests simulating 100+ concurrent VPN sessions, ensuring 99.9% uptime during COVID-19 remote shift

Vision TV Entertainment

Cofounder & Lead Engineer

Jun 2016 - Apr 2017 Athens, Greece

Conceptualized and created innovative OTT content delivery platform using Python, Linux, and Raspberry Pi

Integrated platform into one of Greece's largest telecom networks

Certifications & Awards

Professional Certifications

Finance

Machine Learning for Trading Specialization

Coursera / Google Cloud

2025

Advanced machine learning techniques applied to quantitative trading and financial markets.

Verify Certificate

Finance

Quantitative Finance & Algorithmic Trading

Udemy

2025

Comprehensive course covering quantitative finance, algorithmic trading strategies, and Python implementation.

Verify Certificate

Engineering

AI Engineering Professional Certificate

Coursera / IBM

2024

Professional certification in AI engineering, machine learning, and artificial intelligence systems.

Verify Certificate

Engineering

Ultimate Rust Crash Course

Udemy

2024

Comprehensive Rust programming course covering systems programming and performance optimization.

Verify Certificate

Awards & Recognition

1st Place

Best Information System & IoT Application

Industry Award

2022

Dynamic Workflow Management System (DEDA S.A.) - Award-winning enterprise platform.

Top 3

Athens Startup Weekend

Vision TV Entertainment

2017

Innovative OTT content delivery platform for the Greek market.

3rd Place

Mathematics Contest "Thalis"

Hellenic Society of Mathematics

2008

National mathematics competition showcasing analytical and problem-solving skills.

Speaker

18th InfoCom World Conference

Technology Conference

2016

Presented Vision TV Entertainment startup at major technology conference.

Skills

Programming Languages

Python JavaScript TypeScript C++ Go Rust SQL

Quantitative Finance & Trading

Algorithmic Trading Order Management Systems High-Frequency Trading Quantitative Analysis Risk Management Financial Modeling Market Data Processing Digital-Asset Platforms Settlement & Reconciliation

Backend & APIs

Django FastAPI Flask Node.js REST APIs GraphQL Microservices SQLAlchemy Pydantic Celery

Data & ML

Pandas NumPy Scikit-learn TensorFlow PyTorch Apache Airflow Jupyter

Cloud & DevOps

AWS Azure Docker Kubernetes Google Cloud Git CI/CD Azure Container Apps Azure DevOps Microsoft Entra ID Bicep OpenTelemetry Prometheus Grafana

Databases

PostgreSQL MongoDB MySQL Redis Supabase InfluxDB Elasticsearch TimescaleDB

Frontend Development

React Next.js HTML5 CSS3 Flutter Material-UI Responsive Design

Blockchain & Web3

Solidity Ethereum Polygon Hardhat Foundry Solana Web3.js Hyperledger Besu