How Should I Structure a Web App That Needs Real-Time Updates

I’m working on a web application that needs to display data that changes frequently, and I’m trying to decide on the best architecture.

For example, users may need to see updates immediately when a new record is created, an order status changes, or another user performs an action. I’m considering polling the backend periodically, but I’m concerned about unnecessary server requests as the number of users increases.

Would WebSockets be a better choice for this type of application, or would Server-Sent Events be sufficient?

I’d also like to understand how developers handle reconnects, authentication, and server scalability when using real-time communication.

What approach has worked well for you in production web applications?