Full-Stack Developer for AI Web App

I need a full-stack developer to build a simple web application for an academic research study. Participants will access the application from a Qualtrics survey, have a voice conversation with an AI assistant using the OpenAI API, and then automatically return to Qualtrics to complete questionnaires. The application should support two experimental AI conditions, capture conversation transcripts, record participant metadata (ID, timestamps, condition, duration), and securely store the data for export. This is a research interface—not a commercial chatbot—and the focus is on reliability, security, and clean integration with the OpenAI API. Experience with React, Node.js, and OpenAI API integrations is preferred.