Lefteris Fthenos

MSc in Business Analytics | Business Analytics Assistant Manager

About Me

I hold a Bachelor's degree (BSc) in Accounting & Finance and a Master's (MSc) in Business Analytics from the Athens University of Economics & Business, where I graduated second in my class with a GPA of 9.01/10. What really drives me is the intersection of data, technology, and business performance - I'm genuinely curious about how things work and restless when it comes to learning new technologies.


That curiosity is exactly what pushed me beyond my accounting and finance background into business intelligence and web development. I can't help but dive into new challenges, whether that's building data solutions in Python and SQL, creating dashboards in Power BI, or developing full-stack applications with Flask, Django, JavaScript, and HTML/CSS.


I work with strong principles and love collaborating with teams to tackle tough problems. I'm always looking for ways to innovate and push boundaries, and I genuinely believe that continuous learning isn't just important - it's what keeps the work exciting and meaningful.

Business Analytics

Transforming data into actionable insights that drive business decisions

Full Stack Development

Building responsive web applications with Django, Flask, and modern front-end technologies

Process Automation

Streamlining workflows and business processes with custom solutions


Languages

Greek: Native | English: Full Professional (CEF C2)

Professional Experience

Business Analytics Assistant Manager

Mitsis Group January 2025 - Present

Leading business analytics initiatives and managing data-driven projects across the organization.

Senior Business Analyst

Mitsis Group August 2023 - January 2025

Developed and implemented data-driven solutions to optimize business processes and improve decision-making.

Business Analyst

Mitsis Group October 2022 - August 2023

Analyzed business requirements and translated them into technical specifications for development teams.

International Expansion Manager

DayTrip4U April 2019 - March 2021
  • Slashed firm's costs 15% by introducing a new business strategy for vendor product management
  • Managed competition analysis using tools like Price2Spy and Google Analytics
  • Developed expansion strategies for new markets based on thorough research and analysis
  • Conducted financial analysis for all projects and established team guidelines

Education

Master of Business Analytics (MSc)

Athens University of Economics and Business

August 2022 - August 2024

Graduated second in class with a GPA of 9.01/10

Bachelor at Accounting and Finance (BSc)

Athens University of Economics and Business

2016 - September 2021

Certifications

  • Excel Crash Course - Spreadsheet Formulas for Finance
  • SEO Foundations
  • Edexcel Level 3 Certificate in ESOL International (CEF C2)
  • Grow Greek Tourism by Google
  • Microsoft Power Platform Fundamentals

Publications

Investigating Optimization Techniques for the Consistent Vehicle Routing Problem with Heterogenous fleet (Link)

Technical Skills

Data & Analytics

Python Analytics
99%
Power BI
100%
SQL/MySQL
95%
Power Automate
70%
Power Apps
65%
Redis / MongoDB
60%

Frontend Development

HTML5
95%
CSS3
90%
JavaScript
85%

Backend Development

Python
95%
Django
90%
Flask
95%
FastAPI
80%

Featured Projects

A selection of my professional work

Web Applications

Cashflow Management System

A web application built with Flask (backend) and Bootstrap (frontend) that streamlines financial and operational management for enterprises. The system enables accountants, auditors, and executives to design, submit, and approve cashflow programs (payments, revenues, intercompany transactions) with automated data processing using Pandas/Numpy. It features reporting dashboards, Power BI integrations (via REST API), and role-based workflows for approvals and audit controls. Admin tools support payroll, taxation, partner agreements, and archival of financial data, ensuring transparency and compliance across departments.

Daily Employee Attendance

A Daily Attendance Management System built with Django, Bootstrap, SQL Server, and Azure AD authentication. The app enables role-based workflows for Payroll teams, Managers, and Accountants, ensuring accurate daily attendance validation and approvals. It integrates with the Azure Data Warehouse of the company for automated time-tracking data, supports corrections via resubmissions, and enforces deadlines for compliance. Managers confirm staff records, Accountants finalize validations, and Payroll oversees consistency—providing secure, auditable attendance records with export and reporting features.

The app was deployed on an NGINX server, running Gunicorn as the WSGI server.

Proforma Invoice Application

A Flask-based web application that automates the generation of proforma invoices for travel agencies by extracting and processing reservation data from SQL Server. The system performs ETL operations on upcoming reservations, applies caching for faster performance, and delivers exportable proforma documents. It integrates with the organization’s BI infrastructure and was deployed on an Apache server with WSGI, ensuring secure and efficient access for multiple users.

TrustYou Analytics Dashboard

Mitsis TrustYou Analytics Dashboard, a Flask-based web application that integrates with the TrustYou API to provide real-time insights on customer reviews across hotels. Key contributions include: • building interactive dashboards with KPIs and trend monitoring • enabling review exploration by category, sentiment, and date • implementing impact score analysis linking feedback to operations • automating Excel-based reporting for management • deploying with a stack of Python (Flask, Pandas, NumPy, Requests, OpenPyXL), HTML/CSS/Bootstrap, and JavaScript. This system empowered Mitsis Hotels to systematically monitor guest sentiment, optimize departmental performance, and improve overall online reputation and customer satisfaction.

HConVRP Solver

Developed a Heterogeneous Consistent Vehicle Routing Problem (HConVRP) solver and interactive web application as part of my thesis to demonstrate advanced optimization and software engineering skills. The project involved: • implementing a Flask-based web interface with live step-by-step logs via WebSockets • designing a Python solver leveraging Pandas, NumPy, scikit-learn, and YAML datasets • modeling the HConVRP with constraints on vehicle capacities, time windows, frequent customer consistency, and depot return requirements • integrating constructive heuristics, Hierarchical Tabu Search (HTS), and Variable Neighbourhood Descent (VND) for solution optimization • providing visualization of routes, solver progress, and performance metrics • structuring datasets in both .txt and .yaml formats for reproducibility • enabling fleet and customer management with heterogeneous vehicles and multi-period planning.

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