Kostas Familonidis, Developer in Pireas, Athens, Greece
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Kostas Familonidis

Verified Expert  in Engineering

Full-stack Developer

Location
Pireas, Athens, Greece
Toptal Member Since
June 18, 2014

Kostas is a passionate full-stack developer, most recently focused on internationalization projects and cross-platform mobile app development, and experienced with a variety of other projects and platforms, from business process automation to finance and beyond.

Full-stackWebhooksBack-end DevelopmentSaaSCustomer Relationship Management (CRM)Ruby on Rails (RoR)RubyGitUbuntuLinuxRedisMySQL DaemonRed Hat LinuxRSpecReact

Portfolio

Getaway House
Ruby, JavaScript, API Integration, Full-stack, Ruby on Rails (RoR), HTML...
Procore
RSpec, Functional Programming, Unix, Object-oriented Programming (OOP), HTML...
Vertical Scope, Inc.
Functional Programming, Unix, HTML, CSS, JavaScript, React Native, React...

Experience

Ruby - 12 yearsRuby on Rails (RoR) - 12 yearsJavaScript - 9 yearsFull-stack - 8 yearsRSpec - 7 yearsReact - 6 yearsReact Native - 2 yearsD3.js - 1 year

Availability

Part-time

Preferred Environment

Unix, Linux

The most amazing...

...thing I've developed is a CRM that integrates mail services in mobile devices.

Work Experience

Full-stack Web Developer

2021 - PRESENT
Getaway House
  • Developed the application stack for enabling multiple payment processors using Ruby, Ruby on Rails (RoR), JavaScript, and React.
  • Improved code quality to support message queuing under the CQRS pattern.
  • Designed robust services based on task-based UI (user interface) analysis.
  • Implemented TDD (test-driven development) and extensive acceptance-test coverage in line with Agile development practices.
Technologies: Ruby, JavaScript, API Integration, Full-stack, Ruby on Rails (RoR), HTML, Architecture, Back-end Development, Customer Relationship Management (CRM)

Full-stack Web Developer

2019 - 2021
Procore
  • Developed the application's stack to support internationalization across the platform.
  • Modernized existing parts of the codebase using the latest Ruby and JavaScript patterns, RSpec, and UI (user interface) functional testing.
  • Performed auditing and regression tests analysis on tools enforcing internationalization and localization standards.
  • Reviewed code and supported the team's internal QA (quality assurance) process.
  • Implemented TDD (test-driven development) and extensive acceptance-test coverage in line with Agile development practices.
Technologies: RSpec, Functional Programming, Unix, Object-oriented Programming (OOP), HTML, Git, Redis, JavaScript, Ruby on Rails (RoR), Ruby, React, Webhooks, Full-stack, Node.js, APIs, SaaS, Code Architecture, REST APIs, API Integration, Architecture, Back-end Development

React Developer

2016 - 2018
Vertical Scope, Inc.
  • Developed cross-platform native mobile applications in iOS and Android using JavaScript and React Native.
  • Developed and integrated React components into a forum website using Redux architecture.
  • Improved UX (user experience) and UI (user interface) performance on mobile applications.
  • Reviewed code and supported the team's internal QA (quality assurance) process.
  • Implemented TDD (test driven development) with Agile development practices.
Technologies: Functional Programming, Unix, HTML, CSS, JavaScript, React Native, React, Webhooks, Node.js, Project Management, APIs, Code Architecture, Redux, Redux-Saga, REST APIs, Architecture

Full-stack Web Developer

2017 - 2017
Pivot.io, Inc.
  • Developed an application for automating business processes in Ruby, Ruby on Rails, JavaScript, and GraphQL.
  • Developed and integrated React components using Redux and sagas for concurrent data structures.
  • Transitioned REST (representational state transfer) APIs and micro-services in GraphQL implementations.
Technologies: Unix, Object-oriented Programming (OOP), Git, GraphQL, React, Ruby on Rails (RoR), Ruby, Webhooks, Full-stack, Node.js, APIs, SaaS, Code Architecture, Redux, Redux-Saga, Architecture, Back-end Development

Software Engineer

2015 - 2015
Sky UK, Ltd.
  • Developed full-stack applications using microservices in Ruby, Sinatra, and JavaScript.
  • Utilized A/B testing to validate product efficiency on customer retention rates.
  • Maintained and developed multiple custom rack middlewares in Ruby.
  • Implemented TDD (test driven development) with Agile development practices using RSpec.
Technologies: RSpec, Functional Programming, Unix, Object-oriented Design (OOD), Object-oriented Programming (OOP), Ubuntu, Rack, HTML, TeamCity, Git, SQL, Redis, jQuery, Sinatra, Ruby, Webhooks, APIs, SaaS, REST APIs, Architecture

Lead Developer

2013 - 2015
Ringley, Ltd.
  • Developed full-stack applications on the intranet/extranet deployed to the cloud.
  • Handled back-end system administration and infrastructure configuration to prepare for distributed computing.
  • Developed a contract management system for tracking job completion and staff performance.
  • Implemented and designed a back-end storage system for optimized performance in MongoDB and MySQL.
  • Implemented and designed an Elasticsearch cloud-based search engine solution.
  • Modernized existing Ruby on Rails applications by extracting business logic, using unit testing, and making use of JavaScript, Ruby, and Ruby on Rails engines.
  • Exposed secure web APIs to integrate with mobile applications.
  • Developed a financial application that monitors and calculates cash flows, payments fees, and percentage fees.
  • Restructured and introduced effective project management methodologies in the organization.
Technologies: RSpec, Functional Programming, Object-oriented Design (OOD), Ember.js, Unix, Ubuntu, GitLab, MongoDB, Sinatra, Elasticsearch, Redmine, HTML, Memcached, D3.js, Git, SQL, MySQL Daemon, Redis, jQuery, Red Hat Linux, CSS, JavaScript, Ruby on Rails (RoR), Ruby, Webhooks, Full-stack, Project Management, APIs, SaaS, Code Architecture, REST APIs, API Integration, Architecture, Customer Relationship Management (CRM)

Software Developer

2013 - 2013
Farncobe
  • Developed a back-end authentication system for a mobile application.
  • Integrated Facebook and Twitter API on the application UI.
  • Developed a full database-driven implementation for multi-language support.
  • Implemented TDD (test driven development) and extensive acceptance-test coverage using RSpec.
Technologies: RSpec, Object-oriented Design (OOD), Unix, PostgreSQL, Ubuntu, HTML, Git, SQL, Redis, Ruby on Rails (RoR), Ruby, Webhooks, APIs, SaaS, REST APIs, API Integration

PMO/Projects Coordinator

2008 - 2012
Intrasoft International
  • Oversaw SLA budgets.
  • Maintained the database backlog for tracking work in progress using Ruby, MySQL, and Linux.
  • Consolidated contracts and delivery of technical documents.
  • Produced and maintained all project documentation, including project plan and project scope.
  • Organized, prepared, and followed up the invoicing procedure, including infrastructure procurement and software license updates.
Technologies: Linux, Redmine, OLAP, Git, MySQL Daemon, CSS, HTML, SQL, Ruby, Bash, Red Hat Linux, Project Management, Customer Relationship Management (CRM)

Basic Skeleton for an Object-oriented JavaScript Framework

https://gist.github.com/kfamilonidis/200221fb1fa6373c778dc3997c94d4d8
I undertook the task of creating a fundamental framework for object-oriented JavaScript programming. My focus was on minimalistic object initialization, emphasizing scope management and extensibility. The initialization function is activated by a self-executing anonymous function which I designed to transfer the scope to the initialization method within the object. This design approach enables the creation of multiple objects while ensuring a significant reduction in scope, enhancing efficiency and clarity.

React and React Native

Developed and enhanced user experiences on multiple forum sites utilizing React and React Native frameworks.

GraphQL Implementation

Built a GraphQL implementation from scratch for utilizing very complex data structures and reporting statistics with minimum time delay.

Basic Setup for Loading TSort in Ruby 3.1

https://gist.github.com/kfamilonidis/e193240de686c7971505e582845e0e04
Topological sorting or TSort is a new built-in method introduced in Ruby 3.1. Its capability is to solve complex dependency problems that can be represented as graphs. One of its uses is in library dependencies resolution, but its use can be extended to many fields, such as task management.

Languages

HTML, JavaScript, Ruby, HTML5, Bash, SQL, CSS, GraphQL

Frameworks

React Native, Sinatra, Ruby on Rails (RoR), Redux, Ember.js

Libraries/APIs

Mongoid, React, jQuery, Redux-Saga, REST APIs, Rack, D3.js, Node.js

Tools

RSpec, Git, TeamCity, Redmine, GitLab

Paradigms

Object-oriented Programming (OOP), Object-oriented Design (OOD), Functional Programming, Metaprogramming, OLAP

Platforms

Linux, Ubuntu, Red Hat Linux, Unix

Storage

Elasticsearch, Redis, MongoDB, MySQL Daemon, PostgreSQL, Memcached

Other

Webhooks, Full-stack, APIs, SaaS, Code Architecture, API Integration, Architecture, Back-end Development, Customer Relationship Management (CRM)

Industry Expertise

Project Management

2000 - 2004

BSc Degree in Business Administration (Technology)

University of Patras - Patras, Greece

SEPTEMBER 2012 - SEPTEMBER 2015

Red Hat Linux System Administrator

Red Hat