The line between front-end and back-end development and what they mean has become increasingly blurred.
In the days of server-side rendering, the "back end" implemented the user interface. However, technology changes have made it so the user interface is implemented on the front end. Many software frameworks and languages can be used for both server-side and user interfaces — so where’s the real distinction between “front-end” and “back-end” development?
Here’s what you need to know about front-end vs. back-end development, popular languages and frameworks for each, and some of the biggest challenges you may face in either kind of development.
With the introduction of jQuery/AJAX and later Angular/React, user interface rendering shifted to the front end. Today, some frameworks like Next.js can render React components on both the front end and the back end.
The modern distinction between “front end” and “back end” now generally applies to whether something is done on a client (i.e., web browser or mobile application) or on a server. However, the biggest difference comes down to the code that a developer is working on and whether it applies to the user interface or an Application Programming Interface (API) consumed by software and not a real person.
Front-end development is when developers work on code that runs on a client, which typically ties closely to the user interface. The code applies to visual elements that users can see and directly interact with — like logos, font, colors, search functions, and more.
The most popular languages used in front-end web development include:
These are the most popular choices due to native web browser support, though sometimes developers will write code in other languages that compile down to a natively supported lanaguage.
Back-end development typically refers to work done on a server under the organization's control. Nowadays, this development is usually done where the interface is an API consumed by other software — rather than a user/person, like in front-end development.
Some of the popular languages for back-end development include:
While the line between front- and back-end development is increasingly blurring — especially as many developers opt to use the same language and framework in full-stack development — there are some key differences for software engineers to keep in mind.
One of the most obvious, notable differences between front-end and back-end code is who it’s for.
In front-end development, code will affect what a user sees and interacts with on a website or mobile application. While back-end code will ultimately still affect the user and how a website or application runs, they won’t directly see or interact with its functions.
Ultimately, it boils down to who the developers are writing and editing the code for: the users or other software modules.
One of the significant differences between front and back end development is the trust you can have in either and the security it has.
Code running on the back end is under your control. Therefore, you can trust it to perform security-sensitive operations like checking passwords and processing payments.
However, it’s a different story with code on the front end. Code on the client could be manipulated by malicious actors, like someone trying to hack the system. Therefore, the server should not depend on it functioning properly for security purposes.
Keep this in mind when writing and editing code, and ensure your development team takes proper precautions to keep not only your data, but any user data secure.
However, there’s more language diversity in back-end development.
In mobile app development meanwhile, not only are developers faced with deciding which language is best for the front or back end — they also have to consider the language requirements for the platform the app will run on.
As the app serves as the front end, developers are often faced with molding to the favored language for the platform it will run on, like Android or iOS. Popular languages for Android app development include Java and Kotlin, while Objective-C and Swift are common choices for iOS.
This is especially helpful when creating apps across multiple platforms that may have different language requirements.
Java and Python are also often-used back-end development languages.
Just as some coding languages are used in both front-end and back-end development, some frameworks can work for both the front end and back end.
However, some frameworks may be used more for one or the other.
Front-end and back-end frameworks
These frameworks will, of course, depend on if different languages are used in front- and back-end development or if the same language is used for both.
Another distinction between front- and back-end development is the challenges and constraints developers face when working with either.
Because service development doesn't involve anything visual, developers don’t have to be concerned about user experience problems like they do for user testing in front-end development. Back-end code also tends to be easier to test because you can run automated tests in a limited and controlled environment.
Meanwhile, with front-end code, you have to test user interfaces in any browser your customers might use. This can make testing processes challenging, and results can be unreliable.
In user interface development, performance bottlenecks tend to occur during the rendering process when displaying a complex set of elements.
However, when developing back-end service APIs, performance bottlenecks may occur in core processing algorithms or databases. These are less likely to become bottlenecks in the user interface because the front end only handles small slices of data.
While once two distinct elements of development, the line between front- and back-end processes has increasingly blurred.
The key differences developers will need to keep in mind are who the code is for and the challenges they will face when testing software and fixing bugs.
Whether focusing on front-end, back-end, or full-stack development, teams will be better equipped to effectively create and maintain software when keeping these key differences in mind.