Giorgos A.

Data Scientist

660 dollar
13 years
Athens, GREECE

My experience

FreelanceNovember 2020 - Present


ToptalOctober 2019 - November 2020

- Managed technical team, being responsible for hiring, planning, and output of the teams. We have been building GQL interfaces and infrastructure necessary for other engineering teams in the company. The team consisted of 7 people.

- Also leading the onboarding team, building everything that’s needed for new clients to sign up


Data Scientist / Data EngineerJanuary 2017 - September 2019

I lead the News Recommendation Team, responsible for building a Recommender System for News Articles. We are using a combination of different techniques, including Logistic Regression, Collaborative Filtering and others. Using Scala and the Play Framework, as well as Hive and Spark for the Machine Learning part of the algorithm. All the applications were hosted internally, using Docker and Kubernetes. Other tech- nologies used include MySQL, ZeroMQ, Redis, Memcache.

XingNovember 2012 - December 2016

Senior Backend Engineer, working mainly with RoR. I have worked in different teams, include teams responsible for very mission critical and high traffic portions of the platform.

Ruby on Rails Freelance DevelopmentDecember 2009 - October 2012

Develop Web Applications for various clients

Skroutz.grNovember 2011 - October 2012

Ruby on Rails, some C++ development

Computer and technology Institute, Patras, GreeceMarch 2008 - December 2009

- E-voting system PNYKA ( (JAVA)
- Ditigizing Sytems (

My stack

Analysis methods and tools

Subversion (svn)


AJAX, jQuery, REST

Application servers



Scala, Bash, Python, ASP.NET, Ruby, C++, XML, JavaScript, PHP, Matlab, CSS

Environment of Development



MongoDB, MySQL

Big Data

Hadoop, Spark

IT Infrastructure

Linux, Git

My education and trainings

Master's Degree in Computer Engineering - University of Patras2008 - 2012

Bachelor's Degree in Computer Engineering - University of Patras2001 - 2007