Experienced AI Full-Stack Developer for SaaS Application

We're looking for an experienced AI full-stack developer to help resolve issues in our existing AI-powered SaaS application. The app allows users to upload PDF documents, ask questions, and receive AI-generated answers based on their files. However, we're facing issues with inaccurate AI responses, document retrieval, occasional API failures, and slow response times. We need someone who can review the existing codebase, identify the root causes, and fix these issues without rebuilding the entire application. Requirements: - Strong experience with React, Next.js, Python, or Node.js. - Experience integrating OpenAI or other LLM APIs. - Knowledge of RAG pipelines, embeddings, and vector databases. - Ability to debug APIs, optimize performance, and resolve frontend/backend issues. Please share examples of similar AI applications you've worked on and briefly explain how you'd approach troubleshooting these problems. We're looking for someone who can start with an initial assessment and then implement the necessary fixes.