Olexii Kasianenko — Ruby Full-Stack Engineer

Expertise in Full Stack Web (10.0 yr.), Back-End Web (10.0 yr.).

Last verified on August, 2026

Core Skills

Bio Summary

Over 10 years of expertise in Ruby and Ruby on Rails, specializing in scalable web applications, PostgreSQL optimization, and REST/GraphQL API development.
Proven track record in designing modular microservices architectures and implementing automated KYC systems, enhancing verification success and reducing manual workload.
Extensive experience with Angular (5+ years) and React for full-stack development, delivering high-traffic social networks and CRM platforms.
Skilled in performance tuning, reducing API latency by ~30%, and integrating advanced features like face recognition to streamline moderation.

Technical Skills

Programming Languages	JavaScript, Ruby, TypeScript
JavaScript Frameworks	Angular, React
Ruby Frameworks	Ruby on Rails, Sinatra
Databases & Management Systems / ORM	MySQL, PostgreSQL
Cloud Platforms, Services & Computing	AWS
Virtualization, Containers and Orchestration	Docker
Version Control	Git
SDK / API and Integrations	GraphQL, RESTful API
QA, Test Automation, Security	RSpec

Work Experience

Ruby Engineer - DIDWW (Modular CRM platform and automated KYC verification system)

Duration: 2022 – Present
Summary: Development of a modular CRM platform using interconnected Ruby on Rails microservices for telecom communication management, including an automated KYC verification system to improve verification success and reduce manual workload.
Responsibilities:

Designed and developed CRM platform with 3 Ruby on Rails microservices.
Implemented automated KYC verification system.
Enhanced backend reliability, performance, and maintainability of customer-facing services.
Collaborated with product managers, QA engineers, and stakeholders in an international Agile environment.

Technologies: Ruby on Rails, PostgreSQL, REST APIs, AWS

Ruby Engineer - Anadea Inc (Dutch e-commerce platform and German educational platform)

Duration: 2021 – 2022
Summary: Maintenance and optimization of a large-scale Dutch e-commerce platform and extension of a German educational platform with new features and stability improvements, working with European clients in distributed teams.
Responsibilities:

Maintained and optimized backend and database of Dutch e-commerce platform.
Delivered performance enhancements reducing response times.
Extended and supported German educational platform with new features and fixes.
Collaborated directly with European clients in cross-functional distributed teams.

Technologies: Ruby on Rails, PostgreSQL, JavaScript

Full-Stack Engineer - Minichat.com (Minichat.com social network platform)

Duration: 2015 – 2021
Summary: Built and maintained a high-traffic social network platform with Ruby (Sinatra) backend and Angular frontend, including internal content management and moderation tools and real-time high-concurrency backend services.
Responsibilities:

Developed backend services using Ruby and Sinatra.
Built frontend with Angular.
Created internal content management and moderation tools.
Optimized PostgreSQL queries to reduce API latency.
Integrated face recognition module to reduce manual moderation time.
Architected backend for real-time, high-concurrency workflows.

Technologies: Ruby, Sinatra, Angular, PostgreSQL, REST APIs

Education

Master’s Degree in Computer Systems and Networks
Kryvyi Rih National University
2006–2011

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