What is a back end
Back-end web development, also called server-side development, concerns creating code to govern the infrastructure supporting websites and web-based applications, i.e., the behind-the-scenes code running on servers upon which functional websites and web apps are hosted. A server is a specialized computer system that features extensive and scalable storage, memory, and processing capability.
In contrast to front-end web development which aims to realize an optimized website/web-app interface, back-end code concerns the efficient utilization of resources available on the server hosting the website/web-app. Web developers host server resources using back-end code: bandwidth, storage, and processing.
Back End Web Development Fundamentals
When a user accesses a website or web app via a browser installed on their device, the user uses the internet to access a remote server that hosts(houses) the website/web app. In this regard, back end developers focus on creating behind-the-scenes/server-side applications that carry out the two core website/web-app functionality-centric tasks:
Accept, Store and Up-date User-defined Information/data Input
The server-side app accepts information/data fed by the user into a website/web-app user interface on their browser and stores it on the remote server hosting the website/web-app. In this back-end code scenario, the server-side app puts user input into an existing database located on the host server.
A suitable example is how website/web-app passwords and usernames are stored on website/web-app host servers. This behind-the-scenes reality also applies to how specific browsers can securely store a user’s online credentials, e.g., Chrome.
In addition to accepting and storing user information/data, the same server-side app implements information/data updates on the website/web-app host server. For example, a password/username update involves finding the storage location of the old password on a host server credentials database, deleting it, and then replacing it with the new password.
Locate, Retrieve, and Deliver User-defined Information/data Requests
A behind-the-scenes app receives an information/data request, finds the necessary information/data on the host server, and then transmits this information/data to the website/web-app user interface on a web browser running on a user device.
A suitable example is an mp3 download request by a user accessing an online music repository via a web browser on their device. In this scenario, the download begins after a server-side app locates and retrieves the desired mp3 file on the repository’s host server and then delivers it for downloading.
Back-end web developers create behind-the-scenes server-side apps that perform the above objective-specific functions through code. This back-end code shows how server-side apps utilize host server resources to fulfill user-defined tasks.
In this regard, individual host server bandwidth, storage, and processing allocation for a server-side application directly determine the speed with which the user-defined behind-the-scenes task execution occurs, i.e., the greater bandwidth, storage, and processing allocation, the faster the rate of behind-the-scenes performance.
The allocation of the three host server resources also determines how many identical server-side app-specific tasks can occur concurrently. This includes the number of users accessing a website/web app via a web browser who benefit from website/web-page functionality.