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Oleksandr Zabytovskyi

@oleksandrzabytovskyi

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Senior Ruby on Rails engineer building scalable SaaS backends, microservices, and data-heavy API integrations.

Ukraine

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What I'm looking for

I’m looking for a backend Ruby on Rails role building scalable SaaS, APIs, and microservices—where I can improve performance, stabilize data pipelines, and work with third-party integrations using AI-assisted development workflows.

I’m a Senior Ruby on Rails Engineer with 8+ years of backend experience building scalable SaaS products, microservices architectures, and data-heavy integrations. I’m especially focused on performance, reliability, and clean API design that holds up under real production load.

At Docyt—an AI-powered accounting platform—I led implementation of financial reports, optimized large-scale MongoDB operations, and stabilized mission-critical data export pipelines. I extended reporting for real-time P&L, budget tracking, and multi-entity consolidated reports, improving report generation and export reliability while eliminating job failures and ensuring high availability.

Across my career, I’ve built and refactored microservices, implemented REST APIs and third-party integrations (including QuickBooks Online/Desktop), led background processing and data migrations from legacy databases, and maintained strong test coverage with RSpec. I also leverage AI-assisted development workflows (Cursor, LLM APIs) to improve development speed, code quality, and planning efficiency in production.

Experience

Work history, roles, and key accomplishments

Software Engineer

Docyt

Feb 2023 - Mar 2026 (3 years 1 month)

Extended Docyt’s financial reporting modules for real-time P&L and multi-entity consolidated reports. Stabilized and hardened the report export pipeline to eliminate job failures and improved performance via MongoDB optimizations, indexing, and query rewrites.

Ruby on Rails MongoDB PostgreSQL API Design Microservices Architecture Sidekiq Redis RSpec Kubernetes

API Engineer

CarServ

Dec 2017 - Dec 2022 (5 years)

Designed and built custom REST APIs for 5+ client integrations, and implemented background processing services for client-specific requirements. Led data migrations from legacy MDB databases, including product catalogs and historical records.

Ruby on Rails PostgreSQL Redis Sidekiq REST APIs Data Migration Docker RSpec

Ruby on Rails Developer

COAX Software

Sep 2015 - Dec 2017 (2 years 3 months)

Contributed to 5 commercial projects across tourism and real-estate domains, delivering integrations with Skyscanner, Google Maps, and Google Translator APIs. Handled database administration, custom admin panels, and SEO/geolocation features.