Konstantin R.

✅ Expert-Vetted — top 1% on Upwork ✅ 23 years in software, 18 building with Ruby on Rails ✅ 21,500+ hours across 43 clients, 100% Job Success ✅ AI/LLM integration: OpenAI, Anthropic, RAG, agentic workflows I help teams with Rails applications that need to go further than their original design allowed — and increasingly, with adding AI to products that already work. Typical engagements: • Rails version upgrades and legacy modernisation (5.x/6.x → 7.x/8.x) • Performance and scaling — 50K+ requests/day, 5K parallel AI requests/minute • LLM integration into existing Rails products • Architecture reviews, code audits, technical due diligence • Integrations: healthcare (HIPAA/EMR), payments, QuickBooks, Shopify, Zoho, social APIs My tech stack: • Ruby on Rails, Sinatra, PostgreSQL, Redis, Sidekiq • Front-end: Hotwire (Turbo, Stimulus), React, Tailwind • AI: OpenAI API, Anthropic API, RAG, vector search • Infrastructure: AWS, Docker, GitHub Actions • Testing: RSpec, Minitest, TDD I prefer long-term engagements and ongoing partnerships over short-term projects. Available across full European business hours and 9am–6pm US Eastern. Not sure where to start? Message me here — that costs nothing, and I'll tell you straight whether I'm the right fit. If you'd rather see scope and price up front, my Project Catalog has three fixed-price packages: AI integration for an existing Rails app, a Rails version upgrade, and an architecture and performance audit.