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Serhii User

@serhiiuser7

Backend engineer at VERSTAT building Rails platforms and AI-native workflows that cut client task cycles from five days to 1–3.

Ukraine

Message

At VERSTAT, I design and deliver Rails products and shared platform infrastructure, including Rails 8 APIs with generated TypeScript and Dart clients. I’ve shipped six apps to the Apple App Store, including LoudPass and Garagely.

I moved client delivery to an AI-native workflow where coding agents implement and I own architecture, code review, and final decisions. For a client, this helped reduce typical task cycles from about five days to one to three.

At Cybergizer, I introduced an AI-assisted workflow for the Bloomer Health team and designed a therapist dashboard that moved from prototype to production. It used natural-language-to-SQL with validation across sensitive databases and integrated billing and SSO.

At Scompler, I progressed from Full-Stack Developer to Team Lead, working on a B2B content platform serving 450+ corporate clients. I improved performance in critical areas by up to 5x, helped prepare the Rails backend for Go migration, and led major upgrades with zero-disruption production releases.

Experience

Work history, roles, and key accomplishments

Current

Founder and Principal Engineer

Current

Verstat

Apr 2020 - Present (6 years 6 months)

Founded and led an independent software studio, managing a team of up to 10 for international clients and building own products. Oversaw architecture, code review, and delivery quality.

Ruby on Rails Go React Flutter PostgreSQL AWS Docker Kubernetes AI assisted Development

Senior Full-Stack Engineer, AI-Native Delivery

Cybergizer

May 2026 - Aug 2026 (3 months)

Introduced AI-assisted delivery workflow for a distributed team, cutting task cycle time from 5 days to 1-3 days. Designed and shipped a dynamic dashboard system with natural-language-to-SQL and improved production reliability.

Ruby on Rails PostgreSQL React AI assisted Development RAG Natural Language To SQL CI CD

Team Lead

Scompler

Jan 2024 - Sep 2025 (1 year 8 months)

Led a cross-functional squad of 10, managing intake, estimation, and delivery. Prepared the Rails backend for a Go migration and hardened the release process.

Ruby on Rails Go PostgreSQL Redis Sidekiq Elasticsearch React AWS Scrum

Lead Backend Developer

Scompler

Aug 2022 - Dec 2023 (1 year 4 months)

Owned backend architecture and API design, achieving up to 5x performance improvements. Extracted services from the monolith and moved email to AWS SES.

Ruby on Rails PostgreSQL AWS Sidekiq Redis Elasticsearch

Full-Stack Developer

Scompler

Aug 2020 - Jul 2022 (1 year 11 months)

Delivered customer-facing features across Rails backend and React frontend, including multi-tenant accounts and SAML SSO. Built integrations with major social networks.

Ruby on Rails React MobX MST PostgreSQL SAML Social Media APIs

Full-Stack Developer

Techery

Jun 2019 - Aug 2020 (1 year 2 months)

Developed modules for a fintech client, including case participants, debtor interactions, and document workflow, using Rails 5 and Vue.js.

Ruby on Rails Vue.Js PostgreSQL REST APIs

Full-Stack Ruby on Rails Developer

Face IT

Apr 2018 - Jun 2019 (1 year 2 months)

Worked on Rails 3 to 5 web apps and third-party API integrations for outsource clients, including a large marketplace and backend services for an ISP and GPU provider.

Ruby on Rails PostgreSQL MySQL MongoDB API Integration