Serhii K.

The product should outgrow its first version, not be held back by it. I help SaaS founders, CTOs, and product teams build production-grade web applications, scale MVPs, and integrate AI automation that actually works under real user load. Whether you need to ship a market-ready AI product, rebuild legacy backend logic, or scale your Next.js/Laravel architecture without breaking your budget, I take full ownership of the delivery. 🏆 12+ years of full-stack software engineering 🚀 50+ shipped SaaS platforms, web applications, and AI integrations 🔥 Systems built supporting 20K+ active users and 99.9% uptime 💡 CORE EXPERTISE & TECH STACK - Frontend Engineering: React, Next.js (SSR, Performance Tuning), TypeScript, Tailwind CSS, ShadCN - Backend Architecture: Node.js, NestJS, Express.js, Laravel (PHP), REST & GraphQL APIs, WebSockets - AI & LLM Automation: AI Agents (LangGraph), RAG Systems, Claude & OpenAI API Integration, Vector DBs (Pinecone, Qdrant, pgvector) - Databases & Infrastructure: PostgreSQL, Redis, BullMQ, AWS, Docker, CI/CD, Multi-Tenant SaaS Architecture - Monetization & Core Flows: Stripe Subscriptions, Custom Billing Logic, Webhooks, Auth & Security (RLS, RBAC) 🏗️ HOW I CAN HELP YOUR PRODUCT 1. Production-Ready SaaS & MVP Launch - Building scalable multi-tenant SaaS platforms from scratch in short iterations. - Implementing tight security layers, strict auth, and optimized billing/Stripe flows. - Structuring clean, maintainable codebases following KISS, DRY & SOLID principles. 2. AI Architecture & LLM Integration - Embedding autonomous multi-agent systems and custom RAG pipelines to automate business operations. - Dynamic caching, prompt engineering, and context optimization to reduce LLM API overhead by up to 40%. - Implementing semantic search without hallucinations or data leaks. 3. System Rescue, Audit & Performance Optimization - Optimizing database queries, background workers (Redis/BullMQ), and API response times under heavy traffic. - Frontend polish: improving LCP/TTI load times and user conversion rates. - Code audits, tech debt cleanup, and stabilizing real-time sync flows. 🛠️ WORKSTYLE & ENGINE FOCUS I prioritize speed, clean architecture, and rapid execution. I don't just deliver UI components or raw APIs, I focus on end-to-end functionality, high concurrency reliability, and long-term codebase scalability. Need a reliable Senior Developer who takes ownership and builds for actual business results? Hit "Invite" or send a short message to discuss your project!