The Difference Between a Framework and a Library

by Andrii M. on Jan 14, 2022

From C++ and Java to Python and JavaScript, nearly every programming language out there has a rich ecosystem of libraries and frameworks. They have a huge variety of different purposes from specifically front-end or back-end development to focus on specific technologies like AR/VR or an industry such as eCommerce.

Frameworks and libraries are convenient tools used to eliminate the need for developers to reinvent the wheel every time they are trying to solve a common problem. How? Libraries and frameworks give developers access to a plethora of reusable components, features that use code written by someone else. These “shortcuts” enable software engineers to significantly speed up the development process and deliver your solution to market with less effort.

Sometimes developers make the mistake of using the terms Framework and Library interchangeably, which brings entrepreneurs a lot of confusion. But there is a considerable difference between the two. 

Generally speaking, a library is a collection of reusable pieces of code that are meant for specific use cases. Depending on the purpose, a library can consist of different functions, objects, and methods that your developers can reuse and even repurpose. If utilized correctly, a library can save your development team significant time and effort on implementing certain functions in your software solution, instead of having to write them from scratch.

On the other hand, there’s a framework, a software platform that serves as the groundwork for your software solution. A framework provides you with hooks and callbacks that your developers can build upon, and can utilize multiple libraries. Equipped with predefined classes, workflows, and functions, it serves as sort of a blueprint that your team can populate with input data to customize the program and achieve the desired outputs.

To help you understand the difference better, let’s take two most popular JavaScript technologies as an example.

For JavaScript alone, there are currently at least a hundred different frameworks and libraries available with all kinds of different purposes. Serving nearly the same purpose, which is building robust and scalable web applications, Angular and React must be the two most popular JS technologies. But one is a framework, and the other is a library. And the key difference between them is Inversion of Control.

When using React to create a web application, the flow of control is in the hands of your developers. They are in charge of choosing when and where to use snippets of ready-made code provided by the library, and arrange particular app functions into a flow. It’s like telling a program to bring you some books from an actual physical library, and instructing it on when and how to arrange them on your shelf.

When using Angular, on the other hand, you invert the control flow in your application, putting the framework itself in charge of calling the code when it needs it and using that code in a specific way. The framework already knows all the common behavioral and graphical elements. It tells your developers what it needs to complete the program, and all they have to do is simply fill in the blanks in this constructor. Developers plug their code into Angular, and Angular calls the code they plugged in as needed.

Frameworks and libraries are both exceedingly useful tools, and it’s a good idea to learn some of them to see which ones would work best for which specific scenarios.