Konstantinos Karachalios, Software Developer in Berlin, Germany
Konstantinos Karachalios

Software Developer in Berlin, Germany

Member since January 26, 2017
Konstantinos is a programmer, and he doesn't just work as one—he's been coding since he was 12 (on BASIC). He sort of accidentally went to a filmmaking university but dropped out to get back to programming. He's never stopped exploring different ways to code and for stuff to code since then. He's lived around Europe and worked on building many web services—most often with Ruby on Rails—which has allowed him to develop with great adaptability.
Konstantinos is now available for hire



  • Ruby, 7 years
  • Ruby on Rails (RoR), 7 years
  • Behavior-driven Development (BDD), 6 years
  • Agile, 5 years
  • Docker, 3 years
  • Node.js, 1 year
  • Rust, 1 year


Berlin, Germany



Preferred Environment

macOS, Atom, Git

The most amazing...

...work I've done was to rewrite a part of a Perl monolith in Rails and deployed it with zero downtime regardless of the millions of requests it served each day.


  • Ruby Developer

    2017 - PRESENT
    • Developed the digital banking solutions on a micro-services architecture.
    • Interviewed potential hires.
    • Aided in the transformation towards agile development.
    Technologies: Ruby, RESTful API, Git, GoCD
  • Senior Developer

    2016 - 2017
    Tesco (via ThoughtWorks)
    • Built a robust solution that integrated with many other services as part of a client onboarding flow.
    • Developed and maintained a flexible deployment platform built on AWS.
    Technologies: Node.js, JavaScript, React, Redux, AWS, Jenkins
  • Senior Software Engineer

    2015 - 2016
    • Migrated a Rails app from Heroku to AWS.
    • Took responsibility of the application's security and data privacy.
    Technologies: Ruby on Rails, Angular, PostgreSQL, Redis, Heroku, AWS
  • Software Engineer

    2013 - 2015
    • Developed a recruiting tool with the back-end code written in Ruby and Rails and the front-end code in JavaScript and Backbone and later rewrote it in CoffeeScript and Marionette.
    • Migrated one of the most traffic-intensive parts of the platform to Rails and its data to a new schema with zero downtime.
    Technologies: Rails, Backbone, AMQP, Riak, MySQL
  • Web Developer

    2008 - 2012
    • Rewrote a gaming news website from PHP to Rails.
    • Developed a simple bug-tracking tool (Bugja).
    • Took responsibility of the back-office application.
    • Developed a simple visual programming language for the moderators to automate part of their tasks.
    Technologies: Ruby on Rails, jQuery, Sass, MySQL, MongoDB, Memcached, Varnish, Sphinx, Elasticsearch


  • Racer Maker (Working Title) (Development)

    A video game where the player is teaching a bot to race. It is still in very early stages of development and has served as a test bed for experimenting with machine learning.


  • Languages

    Ruby, Rust, JavaScript
  • Frameworks

    Ruby on Rails (RoR), Redux
  • Libraries/APIs

    Node.js, React, AMQP, REST APIs
  • Tools

    Git, AWS ECR, AWS CloudFormation, AWS SES
  • Paradigms

    Test-driven Development (TDD), Behavior-driven Development (BDD), Agile, Object-oriented Programming (OOP)
  • Platforms

    Docker, Blockchain, Linux
  • Storage

    MongoDB, MySQL, Redis, AWS S3
  • Other

    Machine Learning, Code Reviews


  • Course Certificate in Machine Learning
    2015 - 2015
    Stanford University | Coursera - Online
  • Statement of Accomplishment in Introduction to AI
    2011 - 2011
    Stanford University | Coursera - Onlnine

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