React Deployment & API Setup

I have a small React.js web application ready for production on a private domain. The cPanel account is already live, so I only need help with specific tasks—things like creating the production build, configuring the document root, handling SSL, setting environment variables, and making sure the deployment script runs smoothly each time I push fresh code. Once the site is live, I also need a clean, documented API that external partners can call securely. A lightweight REST endpoint is fine; just be sure it validates requests, returns JSON, and is ready for basic authentication or token headers so it can plug straight into their platform. Please bring solid cPanel experience, comfort with React-friendly build tools (npm, Yarn, Webpack or Vite), and the ability to test the new API from an external source so we both know it works end-to-end. When everything is running, I’ll just need the deployment notes and the API documentation so I can maintain it going forward.