Sergey F.
AI Automation Projects
Experience
Aug 2024 - Present
1 year 5 monthsAI Automation Projects
FJ Tech
- Designed and implemented AI-driven automations for support triage and analytics (RAG + tool-use flows).
- Integrated LLM services with Rails through secure webhooks, background jobs, and detailed audit logs.
- Added guardrails and fallback logic to ensure human oversight for higher-risk actions.
Feb 2022 - Aug 2025
3 years 7 monthsMusic School Admin Platform
FJ Tech
- Designed and implemented the full backend for managing students, lessons, attendance, billing, scheduling, and reporting across 650+ partner schools.
- Built automated Direct Debit and Stripe billing workflows with retries, scheduling, and reconciliation (Result: debt recovery improved from ~10% to ~90%, replacing manual collection).
- Implemented a hierarchical RBAC system with a configurable permissions matrix stored in JSONB and enforced via Pundit:
- Super Admins (full access)
- Admins (district-level access)
- Area Managers (one or several areas)
- Coaches (restricted to assigned schools/students)
- Per-role read/write or read-only permissions configurable via UI without code changes.
- Delivered Turbo-powered workflows (Frames/Streams) reducing operations workload by 3–8 hrs/week.
- Stabilized large CSV exports with batched/streaming Sidekiq jobs and Active Storage, eliminating timeouts.
- Owned testing strategy (RSpec), CI (GitHub Actions), code quality, documentation, and onboarding/mentoring of two Rails developers.
- Successfully handed over the system to the client’s in-house engineering team in 2025.
May 2021 - May 2023
2 years 1 monthSustainable Food Delivery Platform
FJ Tech
- Built the entire V1 backend architecture: tenants (restaurants), menus, addresses, user accounts, and SMS-based onboarding.
- Implemented full order lifecycle: order creation, confirmation, restaurant prep, courier pickup, ETA/tracking updates.
- Integrated third-party courier API for delivery cost estimates, ETAs, and status polling.
- Automated promotions, fees, commissions, and finance payout CSV generation.
- Delivered sustained feature development post-launch; platform remains in production.
- Built operational tooling (admin dashboards, reports, retries, manual overrides).
Oct 2020 - Aug 2022
1 year 11 monthsInstructor (Rails, JS, SQL, Git/GitHub)
Le Wagon
- Taught full-stack web development (Ruby on Rails), guided students through MVC, relational modeling, and collaborative Git workflows.
Aug 2020 - Present
5 years 5 monthsCo-Founder & Senior Full-Stack Engineer
FJ Tech
- Co-founded and led engineering in a boutique software agency (2–5 people).
- Responsible for technical delivery, architectural decisions, data modeling, CI/testing, and mentoring 2 Rails developers and a Flutter developer.
Summary
Senior full-stack engineer specializing in Ruby on Rails + React/Hotwire, with 5+ years delivering production-grade SaaS systems across EdTech and FoodTech. Experience spans architecture, data modeling, background processing, hierarchical RBAC, payment workflows (Direct Debit + Stripe), and AI-assisted automations. Co-founded a boutique agency and led a small engineering team of Rails + mobile developers. Known for pragmatic, product-focused execution — improved debt recovery 10% → 90%, eliminated CSV timeouts, and saved operations 3–8 hrs/week with Turbo workflows. Seeking mid/senior roles within established teams.
Languages
English
AdvancedEducation
Oct 2008 - Jun 2011
University of Staffordshire
BA, Marketing & Management · Marketing & Management · Stoke-on-Trent, United Kingdom
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