Server Vs. Client

While most of the coding syntax is similar between the server and client, there are some significant differences as well.

Client and Server side:

  • have different roles and responsibilities
  • run inside of different operating environments
  • often don't use the same programming language (except JavaScript!)

The Client/Server Model


  • The client is any part of your web app that the user might interact with, or at the very least have access to. These include:
    • web pages
    • forms
    • Images
    • Interactive elements
  • The server listens for requests from the client, and sends responses
    • mostly just listeners and rules
    • runs in a node.js environment if JavaScript

Client-Side Code

Client-side code is primarily concerned with the appearance and functionality of a rendered web page. This would include:

  • form validation
  • selecting UI components
  • creating layouts
  • nav bars
  • DOM manipulation

Client side is often referred to as the frontend, although they mean slightly different things.

Frontend often refers to a general "realm" of web development, whereas client explicitly refers to an end user's machine and experience.

Server-Side Code

Server-side code is mostly involved in choosing which (or what) kind of information is send back to the browser as part of the response, after receiving a request. This would include:

  • validating form submissions
  • saving, updating, deleting, or reading from a database
  • running logic based upon the request
  • returning a web page and its resources (static)
  • creating and returning a web page dynamically (when the content changes over time)

Can be written in many programming languages, like PHP, Python, Ruby, and NodeJS(JavaScript!) Server side is often referred to as the backend, although they mean slightly diferent things.

backend often refers to the general "realm" of web development that exists separate from the client-side, and server explicitly refers to the hardware and software that are explicitly making that happen.