Many of us know that FP (Functional Programming) and OOP (Object Oriented Programming) are programming styles, but few know what their key distinction is, and when it is better to apply one or another model. In this article, we have gathered all the basic information you may require about each of these models. And then, we will talk a bit about the pros and cons of both paradigms.

Object-Oriented Programming

Object-Oriented Programming (OOP) is the most common and widely used programming model. OOP accentuates using objects and classes. For the application of this model, we need to divide the software variables into so-called classes (object categories) and then build the architecture based on the predefined classes. This paradigm is characterized by a structure that resembles a tree with a rod and branches. Each class inherits properties from its “parent”. And all this together is a complex artificial system that integrates for ease of use of the coding language. OOP-oriented coding languages include Python, Paskal, JS, C ++, Java, etc.

Why is OOP Good?

  • OOP reproduces simple and understandable structures from complex things.
  • You can reuse OOP objects to write other programs.
  • Many libraries and frameworks speed up the development as can be easily integrated into your architecture.
  • A wide segment of OOP developers is ready to assist you in any task.

What Are the Disadvantages of OOP?

In the course of work, there may be some errors because some class is not inherited the way you wanted (since the variables are not strictly typed (means categorized) and some vars can easily go to another class). In a complex system, it will be extremely difficult to detect errors.

If you want to scale the project, it will be complicated, because the larger the program, the more difficult problems arise. The result of a large project is just a huge piece of code that describes class inheritance, cancels something, and introduces exceptions. Changes to the program at the request of the customer will only create a new layer of confusion, the results of which will be more and more errors.

With the introduction of additional functionality, the program can run less smoothly, and usually operates slowly. Finally, it becomes almost impossible to fix something. Very often, when transferring such projects to a new team, it is easier for programmers to start making it from scratch, rather than looking for problems in the existing OOP code.

In FP, everything is more transparent. It’s the family of languages, which is targeted at the creation of complicated systems. Because of the strong typization there is no change in the variable types, everything is more stable and predictable. Code review is quicker, the code is more compact and clear.

Functional Programming

Functional programming is a manner of software engineering in which we try to describe the solution via a mathematical function. This concept of coding belongs to declarative ones. In the OOP, the accent is on “how do we solve this?” At the same time, the FP focuses on “what do we solve?”. Some of the popular functional languages are Haskell, Rust, Nix, Elixir.

What Are the Pros and Cons of FP?

The FP functions are easy to comprehend since they do not alter in any way and depend only on the input data. What output we get from these functions is the outcome of the value they bring. Their signature can give us all the required data about them.

Moreover, the code of the software you are writing becomes simpler to interpret. The reason is that FP languages can perceive functions as values, or vice versa – they transmit different values to functions presented as parameters.

With FP, it is easy to test software and fix bugs. The functions, in this case, are simple – they take into account the argument and generate the original data. They guarantee that they will not generate redundant or secondary data that will not be easy to understand or count.

As for disadvantages, the introduction of pure functions can demand from the developer to get out of the box of OOP thinking and begin to work with the programming as with the mathematical case. Furthermore, if it is simple for you to introduce all the functions it will be burdensome to incorporate them into a unified software unit. As one of the examples of these difficulties, I can mention that it is rather unusual for OOP programmers to code recursively instead of using the loop method.

What is the Difference?

Here are the key distinctions between FP and OOP:

  • Functional programming pays attention to a functional approach to writing and implementing software. While OOP, as its name suggests, focuses on using objects as central coding elements and the integration of ready functions and frameworks.
  • FP uses a fixed data structure, while OOP applies a variable one.
  • The functional approach is characterized by a declarative coding model, while the OOP pays attention to imperative coding.
  • FP is compatible with parallel coding, though the OOP concept rarely does so.
  • There is no definite order for the statements to fulfill during FP. Though, OOP needs to have a static order for the completion of statements.
  • The fundamental components of FP are functions and immutable data, while in OOP in this role are objects.
  • As for applicability, it is accepted in programmers’ circles to lean towards FP, when there are not many things available, but with more operations. While with OOP, the opposite is true: it is more reasonable to choose it when you dispose of many things, but fewer operations.

What do these two ideas have in common? They are both aimed at managing the program state. But still, how they do it is one more distinction between FP and OOP. OOP facilitates state management by breaking it into parts and then compiling it into objects. If these objects in the software are well organized, the software works faster and more smoothly without errors and bugs. With such small objects, you can create great systems and databases. At each level of their complex hierarchy, it will still be easy to understand the relationships between objects and their roles.

In this case, functional programming involves this process in a completely different way. It does not pay attention to facilitating the state management process. It initially completely abolishes such a structure as the state. In essence, the functionality of the FP is transmitted by two fundamental elements: input and output data. The functions depend entirely on the input data, and using the output information, these functions communicate.

So What Should I Use?

Remember that there is almost no software that does not use these two models simultaneously. Yes, OOP and FP perfectly complement each other, but they do not exclude each other. When you create software, you will achieve a good result without using these two models. Therefore, the answer to this question is that you must skillfully combine the functions of both coding models.


Although both OOP and FP are important notions, pursuing the same objective of creating easy-to-use software without errors, their mechanics are opposite. OOP works on an imperative coding model founded on a set of primitives given by the coding language. FP, as opposed, is tightly related to the declarative model.

OOP vs FP is an eternal dilemma. The biggest efficiency in the development of a simple, typical project is OOP, while for the creation of very complicated, scalable, and flexible software systems FP will work better. The best way is to collect all your wishes and share them with the expert development team. They will evaluate your case and provide the most effective and accurate programming solution.

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CTO at Emizentech and a member of the Forbes technology council, Amit Samsukha, is acknowledged by the Indian tech world as an innovator and community builder. He has a well-established vocation with 12+ years of progressive experience in the technology industry. He directs all product initiatives, worldwide sales and marketing, and business enablement. He has spearheaded the journey in the e-commerce landscape for various businesses in India and the U.S.