John Fewell

About

Senior full-stack engineer with 6+ years shipping production Angular and TypeScript applications, currently focused on LLM agent systems and the architecture that makes them actually work in production. Open to senior IC and staff roles, fully remote. I specialize in chat-driven UIs where the LLM is a first-class part of the app architecture rather than a chat bubble bolted onto the side: LangGraph orchestration, typed discriminated-union action surfaces for agent-driven state changes, NgRx Signal Store (withEntities, rxMethod) as the state foundation, and the eval/verification infrastructure that keeps agent behavior honest as the system grows. Stack: TypeScript, Angular 8-20, NestJS, NgRx Signal Store, Node.js, LangGraph, Postgres, Flutter. Previously: Senior Full Stack at Rohirrim, team lead at 3Pillar Global, award-nominated freelance work Based in Toronto, open across Canada and US-remote. If you're building agent systems, AI-native developer tools, or anything where the LLM meaningfully drives the app, I'd be glad to talk.

Experience

Education