Kostas Familonidis, Full-stack Developer in London, United Kingdom
Kostas Familonidis

Full-stack Developer in London, United Kingdom

Member since November 21, 2013
Kostas is a passionate full-stack developer, most recently focused on cross-platform mobile app development but also experienced with a variety of other projects and platforms, from business process automation to finance and beyond.
Kostas is now available for hire

Portfolio

  • Getaway House
    Ruby, JavaScript
  • Procore
    RSpec, Functional Programming, Unix, Object-oriented Programming (OOP), HTML...
  • Vertical Scope, Inc.
    Functional Programming, Unix, HTML, CSS, JavaScript, React Native, React...

Experience

Location

London, United Kingdom

Availability

Part-time

Preferred Environment

Unix, Linux

The most amazing...

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

Employment

  • 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
  • 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, Webhook, Full-stack, Node.js, APIs, SaaS, Code Architecture, REST APIs
  • 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, Webhook, Node.js, Project Management, APIs, Code Architecture, Redux, Redux-saga, REST APIs
  • 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, Webhook, Full-stack, Node.js, APIs, SaaS, Code Architecture, Redux, Redux-saga
  • 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, Webhook, APIs, SaaS, REST APIs
  • 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, Webhook, Full-stack, Project Management, APIs, SaaS, Code Architecture, REST APIs
  • 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, Webhook, APIs, SaaS, REST APIs
  • 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

Experience

  • 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.

Skills

  • 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

    Webhook, Full-stack, APIs, SaaS, Code Architecture
  • Industry Expertise

    Project Management

Education

  • BSc degree in Business Administration (Technology)
    2000 - 2004
    University of Patras - Patras, Greece

Certifications

  • Red Hat Linux System Administrator
    SEPTEMBER 2012 - SEPTEMBER 2015
    Red Hat

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