Oleksii Neishchenko

I’m a Ruby on Rails developer with over 11 years of experience, involved in everything from building systems from scratch to supporting large projects with legacy code. I’ve worked across SaaS, fintech, startups, and eCommerce, consistently owning features end-to-end.

My three biggest wins are establishing processes for code reviews, bug tracking, and code ownership; optimizing Ruby on Rails API endpoints—response time dropped from 90–120 seconds to 1–2 seconds; and integrating multiple third-party APIs (Google Maps, Chargebee, WhatsApp via 360dialog, Brave search, SDB Groep, AFAS).

Recently at FastCTO, I developed and supported internal Rails projects in the fintech sector, built a system to launch and manage background tasks from the front end, and migrated pages/components from Bootstrap 3/4 to Bootstrap 5. Previously, as clevergig Tech Lead / Ruby on Rails Backend Developer, I integrated key APIs and optimized SQL queries, Rails controllers, and Ruby code while explaining trade-offs to stakeholders.

I’m comfortable working with a broad stack—Ruby, Ruby on Rails, Sinatra, multiple databases, Sidekiq/Solid Queue for background work, and modern UI tooling like Stimulus and ViewComponent. I also bring deep performance and systems thinking from building data-collection services and even earlier server administration experience.