How can I create a scalable and dynamic web app using React, Node.js, Express.js, and MongoDB?

I start by using React for the front end to create dynamic, component-based user interfaces. React’s virtual DOM ensures efficient rendering, while its flexibility allows for easy scaling as the app grows in complexity.

Node.js and Express.js provide a robust non-blocking environment. That is perfect for high-traffic situations on the server side. Using Express, API routes, and middleware are dealt with quite efficiently, ensuring that an application remains responsive even during the most unmanageable loads.

I use MongoDB for data storage. It's a NoSQL database that easily scales horizontally. The schema is highly flexible; thus, it allows for quick adjustments while the app is evolving. These feature replications and sharding to handle large datasets.