Client-server interactions are really important for how well full-stack applications work. This is especially true when we talk about web design and RESTful services.

1. Latency and Response Time:

   • Latency is the time it takes for a request to go from a client to a server and back. For local connections, this is about 100 milliseconds, but it can go over 200 milliseconds for longer distances. This affects how users feel about the app.
   • Research shows that if a webpage takes just 1 second longer to load, it can lower sales by 7% (Source: Google).

2. Data Transfer Efficiency:

   • RESTful services usually use JSON, which is a way to format data that makes it smaller. For instance, JSON can be about 30% smaller than XML for the same information.
   • It’s really important to transfer data efficiently because limits on bandwidth can slow things down. As of 2023, the average speed for mobile internet is 50 Mbps. This means we need to make client-server interactions as smooth as possible.

3. Concurrency:

   • With REST APIs, many users can ask for data at the same time. However, if the server is not set up well, it can slow down a lot. A good server can handle over 1,000 requests at the same time (Source: NGINX).

In short, to make full-stack applications work better, we need effective client-server interactions, optimized data formats, and strong server setups.