Full Stack Developer Needed for AI Integration (React + Node.js/MongoDB)

We have a working React + Node.js/MongoDB application in production and we are adding an AI layer on top of it. We are looking for a full stack developer who can own that work end to end, from API integration through to the UI that surfaces it. This is not a greenfield build. The core app is stable and the data model is settled. Your job is to make the AI features feel native to what already exists, not bolted on. What you will build: LLM integration for content generation using existing app data as context Semantic search across user records, moving beyond our current keyword search Automated summarization and classification of incoming records A conversational interface where users can query their own data in plain language Usage tracking and cost controls on the admin side Technical scope: Streaming responses with proper handling on both server and client Embeddings pipeline and vector search (MongoDB Atlas Vector Search preferred, open to alternatives) Prompt caching and token optimization, since we expect meaningful volume Graceful degradation so a model timeout or rate limit never breaks the user-facing flow Clear separation between AI logic and existing business logic, so the app remains maintainable Our current stack: Frontend: React 18, TypeScript, Tailwind CSS Backend: Node.js, Express, TypeScript Database: MongoDB (Atlas) Auth: JWT Hosting: VPS with nginx and PM2 Version control: GitHub, with PR review How we work: Small team, direct communication, no unnecessary meetings. We do a weekly sync call and otherwise work async. We expect PRs with clear descriptions and a short written note when something changes direction. We are technical on our side, so you can explain trade-offs to us directly rather than simplifying.