The server - the brains of the application

The server or middleware layer is the part of your tech stack that interacts with and controls all the other parts.

All of the frontend HTML5 code runs only on the client's machine. This means that if someone views your website on their phone, the code that the frontend of the website is built in is run on their phone. In contrast, the server-side code is executed on the serving machine. In our case, this will be the Raspberry Pi. In this way, we have two machines involved so far - the client and the server.