Oleh Maikovych, Developer in Lviv, Lviv Oblast, Ukraine
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Oleh Maikovych

Verified Expert  in Engineering

Software Developer

Location
Lviv, Lviv Oblast, Ukraine
Toptal Member Since
October 22, 2019

Oleh is passionate about the Ruby programming language and its philosophy. He has solid experience in back-end development on Ruby on Rails framework at any scale. Results-oriented, proactive, and always eager to explore new technologies and approaches, he has the ability to overcome unexpected issues in the fastest manner possible.

RubyRuby on Rails (RoR)ScrumTest-driven Development (TDD)SQLPostgreSQLSidekiqRedisDockerSecurityShellRabbitMQBehavior-driven Development (BDD)Amazon EC2Amazon S3 (AWS S3)Xero

Portfolio

Company in the Domain of Access Management
Amazon Web Services (AWS), Docker, PostgreSQL, Ruby on Rails (RoR), Ruby
Company in the Domain of Education
Xero, Redis, MySQL, Ruby on Rails (RoR), Ruby
Company in the Domain of Childcare
Redis, MySQL, Ruby on Rails (RoR), Ruby

Experience

Ruby on Rails (RoR) - 5 yearsRuby - 5 yearsPostgreSQL - 4 yearsAWS SDK - 2 yearsDocker - 2 years

Availability

Part-time

Preferred Environment

Terminal, Vim Text Editor, OS X

The most amazing...

...thing I've done was improve performance of a critical data processing component by optimizing the algorithm, SQL queries, and paralleling the job processing.

Work Experience

Senior Ruby Engineer

2016 - PRESENT
Company in the Domain of Access Management
  • Implemented integrations with Workday, BambooHR, Namely, and AWS.
  • Built a framework for integration testing based on RSpec, Capybara, and Selenium Web Driver.
  • Bootstrapped projects from scratch.
  • Designed and developed microservices and communication between them.
  • Led a team of seven people.
  • Dockerized microservices.
  • Optimized performance-critical parts of the system.
  • Improved test coverage of one of the legacy parts of the system.
  • Took ownership of legacy source code and improved it to current standards.
Technologies: Amazon Web Services (AWS), Docker, PostgreSQL, Ruby on Rails (RoR), Ruby

Ruby Engineer

2018 - 2018
Company in the Domain of Education
  • Reanimated a project which was unused for three years.
  • Upgraded Ruby and Ruby on Rails versions.
  • Built an invoicing system integrated with Xero.
Technologies: Xero, Redis, MySQL, Ruby on Rails (RoR), Ruby

Ruby Engineer

2015 - 2016
Company in the Domain of Childcare
  • Implemented an administration console.
  • Implemented authorization management for different roles: student, parent, teacher, and administrator.
  • Refactored legacy part of the system.
Technologies: Redis, MySQL, Ruby on Rails (RoR), Ruby

Events Streaming Integrated with Amazon EventBridge

Fully implemented integration with Amazon EventBridge along with streaming service which collected all the system events and dispatched them to AWS.

Framework for Parallel Processing of the Background Jobs

With scale, was encountered an issue with large tasks taking a long time to finish. With performance optimization also was decided to parallel them. For that reason in a background-processing service was implemented a framework that controls the jobs, splits them into small chunks based on different strategies. Chunks can be performed in parallel. Chunks communicate with the main process and can be controlled by it (undo, redo, stop, etc..)

Report Generation System

The system builds a CSV report based on terabytes of data. The challenging part was fetching from the database. For this, I built a complex solution based on DB cursor as well as data traversing in chunks based on the creation date. For efficiency, persistence on AWS S3 was a multipart upload API.

Languages

Ruby, SQL, JavaScript, Haml, Bourne Shell, HTML, CSS

Frameworks

Ruby on Rails (RoR), Redux, Material UI, Selenium

Libraries/APIs

Sidekiq, React

Paradigms

Scrum, Test-driven Development (TDD), Kanban, Behavior-driven Development (BDD), E2E Testing

Platforms

Docker, Amazon Web Services (AWS), Amazon EC2, OS X, Visual Studio Code (VS Code)

Storage

PostgreSQL, Redis, MySQL, Amazon S3 (AWS S3)

Tools

Terminal, Xero, Vim Text Editor, RabbitMQ, Shell, ITerm, AWS CLI, AWS SDK

Other

Security

2012 - 2018

Master's Degree (with Honors) in Cybersecurity

Lviv Polytechnic National University - Lviv, Ukraine

AUGUST 2019 - AUGUST 2022

Amazon Web Services Developer - Associate

Amazon Web Services

NOVEMBER 2016 - PRESENT

Ruby Association Certified Ruby Programmer Silver version 2.1

Ruby Association

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