React / Node.js Developer Needed to Fix API & Data Sync Issues

I’m looking for a full-stack developer to help troubleshoot a few bugs in an existing web application. The application has a React frontend with Node.js and Python services on the backend. Most of the application is working, but we have some issues that need to be identified and fixed. The main problem is related to data not updating correctly between the frontend and backend. In a few cases, the API returns the correct response but the React interface does not immediately reflect the updated data. There are also some backend errors that need to be traced. What I need help with: Reproduce and identify the existing bugs Debug React components and API calls Check the Node.js/Python backend logic Fix incorrect API response/error handling Resolve frontend state/data synchronization issues Test the affected workflows after the fixes Make sure the changes don't break existing functionality There is also an AI/RAG-related module in the application, so experience with LLM/RAG integrations would be useful, although the immediate work is mainly focused on debugging the application. Looking for someone with experience in: React.js Node.js Python REST APIs Django / FastAPI / Flask JavaScript Database/API debugging RAG / LLM integrations Full-stack application debugging I’m not looking for a complete rewrite. I want someone who can look at the existing code, find the actual cause of the problems, and make focused fixes.