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Last updated on 11/28/19

Clients and servers

Now that you understand the difference in scale between the internet and the web, let’s talk about the different parts of the web and where you, the user, fit into the big picture.

 On the web, we have two parties: the client and the server. These words are likely familiar to you, but probably in a more common context, like a restaurant, for example.

In a restaurant, the client makes a request for a specific dish, and the server, or waiter/waitress, responds to that request by retrieving that specific dish and delivering it back to the client. In technical language, these two interactions are called the request and the response, and this exchange is the basis of the web’s client-server relationship.


On the web, the client is the machine that requests the web page. For example, when I type "openclassrooms.com" into my web browser’s URL bar at the top of the window, my computer is the client, and "openclassrooms.com" is the web page that I am requesting


The server is the machine located elsewhere that has that requested file saved inside, and it responds to my request by delivering that file to my computer. A "server", as the name would lead you to believe, is very literally made to serve its clients. This is the device that will send me the web page for "openclassrooms.com" upon my browser's request. You may be familiar with opening documents on your computer. You can think of the client-server exchange as simply opening a file from a different computer.

Those computers can live anywhere in the world, depending on where the site owner or the site's company has bought servers. If I open my browser and type https://www.airbnb.com, my browser sends a request out onto the web for Airbnb, and a server somewhere sends the Airbnb's webpage back to me. That server could be in Virginia, China, etc; it all depends where I am and where Airbnb themselves have servers located.

To recap, in a restaurant setting (unrelated to the internet!), when I request an order of three tacos, the waiter or waitress responds by bringing me three tacos.

When I request to view "openclassrooms.com" in my browser, the server responds by sending me the web page for "openclassrooms.com". 

Now that you understand how client requests and server responses work, let’s check out how information gets from one place to another on the web without getting lost!

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