Konstantin S.

I help founders and product teams ship production AI products and full-stack systems end-to-end: C#/.NET backends, Next.js apps, and native Swift/SwiftUI clients — from architecture and API design to deployment, observability, and maintenance. Best fit when you need one engineer who can bridge product, backend, web, and native surfaces without creating long-term mess. What I usually build: • AI features that work in production: streaming chat, tool/function calling, structured outputs, assistants/workflows, RAG, MCP servers, evals, and cost/latency controls • Full-stack delivery: ASP.NET Core APIs, background workers, auth, integrations, OpenAPI-first contracts, Next.js, Supabase/Postgres, Vercel, AWS, payments, email, and analytics • Native/platform work when needed: Swift/SwiftUI for iOS, macOS, and watchOS; WPF, WinForms, WinUI 3, Avalonia, Uno, VSIX tooling, COM/C++ interop, installers, Telegram Mini Apps, and Chrome Extensions I use AI to accelerate delivery, not to lower the bar: clear contracts, reviewed code, practical tests, instrumentation, and production-ready delivery. If you need a senior engineer who can own the system and ship reliably across backend + web + native clients, send me your goal, current stack, and constraints.