Location: Kyiv, Ukraine

Remote: Yes (UTC+2, flexible)

Willing to relocate: No

Technologies: Ruby on Rails, PostgreSQL, MySQL, Sidekiq, Solid Queue, Redis, HotWire, Stimulus, ViewComponent, Tailwind, RSpec, AWS, Linux. Some Crystal from contract work at Kagi. Claude Code daily.

Résumé/CV: https://www.linkedin.com/in/oleksii-neishchenko-44a23893/

GitHub: https://github.com/alexneisc

Email: [email protected]

Senior Ruby on Rails developer, 11+ years across fintech, SaaS, e-commerce, and startups. Open to full-time remote or contract. What I'm best at: Performance work on existing codebases. Once optimized a set of Rails API endpoints from 90-120s down to 1-2s — measuring first, raw SQL where ActiveRecord produced bad queries, indexing, restructuring background jobs. External API integrations (5+ over my career: Google Maps, Chargebee, WhatsApp via 360dialog, SDB Groep, AFAS). Comfortable with the messy parts — retries, idempotency, webhook ordering, partial failures. Working with legacy and tests-nobody-touches. Reading before writing, refactoring without breaking things. As Tech Lead at clevergig (Dutch SaaS) for 3 years, I set up code review, bug tracking, and ownership processes for a long-lived codebase.

Recent stops: FactCTO (fintech), Rail Europe, Fitjourney.ai, Kagi (Crystal backend), clevergig (Tech Lead).

For fun: building a Rails app + ESP32 device that tracks power outages at my home — the device pings the API every minute, the Rails side aggregates into hours-with-power vs. without. Started during the post-2022 outages in Kyiv and kept evolving — a good way to keep Rails fresh and combine backend with a bit of hardware.