Antonis Berkakis, Developer in London, United Kingdom
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Antonis Berkakis

Verified Expert  in Engineering

Software Developer

Location
London, United Kingdom
Toptal Member Since
June 22, 2020

Antonis is a senior full-stack engineer with a Master of Science degree in computer science and a back-end focus. He writes clean, testable, functional code that can scale. He has developed resilient financial transactions, peer-to-peer systems, and integrations with various protocols. He has honed his skills in demanding fintech environments, climbing to technical leadership and architectural roles. Antonis delivers reliable solutions, transforming ideas into fully functional platforms.

Portfolio

Carwow
Ruby on Rails 5, Elm, Heroku, React Native, Ruby on Rails (RoR), Ruby, Back-end...
Simply Business
Ruby on Rails 5, API Integration, APIs, Redis, RabbitMQ, Docker, RSpec...
Shape and Furnish
Amazon Web Services (AWS), Puppet, DigitalOcean, Capistrano...

Experience

Availability

Part-time

Preferred Environment

IntelliJ IDEA, Terminal, Slack, MacOS

The most amazing...

...system I've developed handles financial transactions and is incredibly resilient.

Work Experience

Senior Software Engineer - Contract

2018 - 2019
Carwow
  • Built a prototype for a mobile app written in React Native in collaboration with another developer.
  • Paired and mentored developers as a part of my everyday routine.
  • Ran A/B tests in many parts of the site and reported back to the product owners.
  • Assisted with multiple Rails apps that were exposing APIs and were also serving dynamic HTML.
Technologies: Ruby on Rails 5, Elm, Heroku, React Native, Ruby on Rails (RoR), Ruby, Back-end, Sidekiq, Scalability, Cloudflare, HTML5

Senior Software Engineer

2017 - 2018
Simply Business
  • Co-developed a React prototype to replace the existing HTML views.
  • Developed an Alexa skill responsible for providing information about transportation in London as part of a hackathon.
  • Acted as an interim lead engineer (tech lead) on one of the core product teams.
  • Refactored big parts of a Rails app and helped upgrade a Rails framework and a few versions of Ruby.
  • Assisted with the introduction of ElastiCache for a scalable and reliable solution for Redis/Sidekiq in Rails.
Technologies: Ruby on Rails 5, API Integration, APIs, Redis, RabbitMQ, Docker, RSpec, ECMAScript (ES6), React, Ruby on Rails (RoR), JavaScript, Ruby, Back-end, Sidekiq, Scalability, HTML5

Software Developer Associate

2014 - 2018
Shape and Furnish
  • Completed a Rails application that was started by another company and prepared its' launch in AWS services.
  • Introduced Bitbucket and Trello apps to track progress for the stakeholder.
  • Minimized the time required to set up a new server using Puppet to set up servers required for the two rails apps.
  • Refactored the payment system that was using Paypal.
  • Introduced the concept of newsletters and offers (coupons).
  • Created a new site in Rails used for the leading company of Shape and Furnish, focusing on landing pages to show samples of work.
Technologies: Amazon Web Services (AWS), Puppet, DigitalOcean, Capistrano, Ruby on Rails (RoR), Ruby, Back-end, Sidekiq

Software Engineer

2016 - 2017
Funding Circle
  • Worked on the back-end development on the Funding Circle's main product, a peer-to-peer lending platform written mainly in Rails apps.
  • Utilized different technologies mainly focused on the investor experience for many Rails apps.
  • Refactored the existing payments system to recover in case of error and report early more readily.
Technologies: Ruby on Rails 5, API Integration, APIs, Jenkins, Chef, RSpec, RabbitMQ, Redis, PostgreSQL, Ruby on Rails (RoR), Ruby, Docker, Back-end, Sidekiq, Scalability

Software Engineer

2015 - 2015
AOL UK
  • Developed a reporting system responsible for AOL ads written in Rails. Refactored main parts to be more error-proof.
  • Introduced a new system based on background jobs using Redis and Sidekiq to replace existing cron jobs. That provided better visibility to non-tech users and embraced that each process was atomic and resumable.
  • Improved deployment time and added extra test coverage from 40% to 96%.
Technologies: Amazon Web Services (AWS), RSpec, Redis, Vertica, Microsoft SQL Server, Ruby on Rails (RoR), JRuby, Ruby, Back-end, Sidekiq

Software Developer

2013 - 2015
IE (Innovation Enterprise)
  • Served as one of the two core Ruby developers for all company projects.
  • Co-created an on-demand training platform for business education in various fields.
  • Developed new projects and maintained existing ones. Reported to the CEO.
Technologies: Ruby on Rails (RoR), Rackspace, CanCan, Capybara, RSpec, Capistrano, Stripe, Back-end, GoDaddy

Shape and Furnish

I took over from the existing development team and reshaped the delivery flow. I introduced different stages in product development, staging and production, and automated tests to prove the app's correctness during new releases. Along with new features like promotional codes and discounts, refactoring on the payment system was developed. Shape and Furnish is an online product of Cabinet Shapes Group, which helps customers build their own bespoke furniture. This was mainly built with Ruby on Rails.

Administrative Interface for Insurance Company

This is a Rails app that gives the admin the ability to upload a driving license, registration of the vehicle, and insurance. It has features such as email and SMS reminders when insurance is due. It can also generate helpful monthly and weekly reports.

Shirtly App

Back-end services for Shirtly's customer-facing and driver apps. Shirtly lets the customers do their laundry by using their phones. People can choose their pick up and delivery slot and pay for their laundry by using any major card. Later, they can track their order and be notified with push notifications about the status of their order. The app also provides active tracking location of their pick up and delivery driver.

Laundry shops can monitor their orders along with their drivers. The app is using reserved time slots, push notifications to iOS devices, and Stripe for payments.

Back End for Wanilla iOS App

I built the back end API for Wanilla. With Wanilla, you can build a native app in seconds using existing design files or from scratch. In a few clicks, you can connect to any back-end service you have access to and distribute your app to unlimited users, instantly.

Languages

Ruby, HTML, JavaScript, CSS, GraphQL, Python, JRuby, ECMAScript (ES6), Elm, SQL, HTML5

Frameworks

Ruby on Rails (RoR), Ruby on Rails 5, Ruby on Rails 4, OAuth 2, React Native, Capybara

Libraries/APIs

Ruby on Rails API, Stripe, REST APIs, Sidekiq, React, Twilio API, jQuery

Tools

Git, Capistrano, Slack, Terminal, IntelliJ IDEA, RSpec, RabbitMQ, Chef, Jenkins, Puppet

Paradigms

Web Architecture, Continuous Deployment, REST, Microservices

Platforms

Heroku, Amazon Web Services (AWS), Docker, Linux, Twilio, MacOS, Rackspace, DigitalOcean

Other

Code Architecture, APIs, Troubleshooting, API Integration, Ruby 3, Back-end, System Design, Data Migration, OAuth, Scalability, CanCan, GoDaddy, Cloudflare

Storage

PostgreSQL, MySQL, Microsoft SQL Server, Vertica, Redis

2007 - 2012

Master of Science Degree in Computer & Communication Engineering

University of Thessaly - Volos, Greece

AUGUST 2015 - PRESENT

edX Honor Code Certificate for Scalable Machine Learning (Apache Spark)

edX

DECEMBER 2013 - PRESENT

University of California at Berkeley via edX

MIT - Massachusetts Institute of Technology

AUGUST 2013 - PRESENT

CS169.2x: Advanced Software as a Service, BerkeleyX

University of California at Berkeley via edX

NOVEMBER 2012 - PRESENT

CS169.1x: Software as a Service, BerkeleyX

University of California at BerkeleyX

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