Add an AI Chatbot to My Website (Small Project)

I have a website and want to add an AI-powered chatbot that answers common visitor questions in natural language. The site is already built — this is a focused addition, not a rebuild.

What I need:

A clean chat widget added to the site (bottom-corner popup style), matching the existing look.
Connect it to an AI API (OpenAI or similar) through a lightweight backend so the API key stays secure.
Ground the chatbot in some basic info about my business so answers stay relevant and accurate.
Streaming responses so replies appear as they're generated.
Works smoothly on desktop and mobile.

Ideal skills:

React / JavaScript.
Experience integrating AI/LLM APIs (OpenAI or similar).
Clean, maintainable code.

Nice to have:

Experience with RAG / grounding a chatbot in custom content.
Familiarity with Next.js.

To apply, please include:

A short note on your experience with AI integrations.
Links to similar work or live examples.
Your availability and estimated price.

Should be quick for someone who's done this before. Looking to start soon.