Although functional programming has existed for almost 60 years, it is currently gaining popularity owing to contemporary developments like data science, machine learning applications, parallel computing, etc. The paradigm of functional programming is growing quickly. We shall examine the most popular functional programming languages in this blog. The functional programming language, common aspects of functional languages, and non-functional languages with functional characteristics will all be covered along the way.
There are many different reasons why people pursue functional programming. While some want to pursue a new job, others want to get better at programming. On the other hand, some people think that functional programming better suits their cognitive approach. Every developer is keen to learn, apply, and take advantage of the rapidly altering landscape to quickly create modern, secure, and valuable solutions.
Keep reading and exploring to learn what is a functional program and the 10 most popular functional languages in 2025.
Table of Contents
What is a Functional Program?
Programming using functions is the technique of creating functional programs. Because functions are “first-class citizens” in this programming paradigm, you may send them as arguments, bound to names. Moreover, it get back from other functions in the same way as any other data type.
Functional programming has historically focused on using the mathematical functions’ inherent purity to create clear, modular, and concise code that intentionally avoids unwanted side effects.
Current functional programming combines pure functions with first-class functions, which capture most of the characteristics of that ideal functional programming, but are not precisely pure.
Functional programming languages comes with two groups:
- Pure functional languages: These languages exclusively accept functional paradigms. One example of this kind of language is Haskell.
- Impure functional languages: These programming languages enable imperative programming and functional paradigms. One popular illustration of an impure functional language is Lisp.
Impure functional languages support both imperative styles and functional paradigms. Python, Rust, and Lisp are typical examples.
Benefits Of Functional Programming
There are benefits to doing things the functional way. We’ll examine the benefits of functional programming in this section.
Code Devoid Of Errors
The functional method indeed eliminates many of the unexpected side effects involved with modifying variables and data, but bug-free programming is a fantasy. Additionally, testing modular functional code is simpler, making it possible to identify and solve any issues that may arise.
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Ensures Better Programming
Regardless of the programming paradigm they choose, developers must adhere to encapsulation, modularity, reliability, and portability as recommended practices.
Your code will automatically become modular, highly testable, and less prone to errors when you use functional programming, especially when working with pure functions.
Excellent For Concurrency
Functional programming that uses stateless functions has the benefit of being excellent for concurrency reasoning. You may easily spread application workloads across several computing power resources to increase performance at scale since each function is stateless.
Simpler To Implement And Test
Writing and maintaining test suites for pure functions is much simpler, as we are aware that the outputs are the same for every set of inputs. It is simpler to test and identify possible issues before they are released into production when you utilize more pure functions in your code.
What Are The 10 Most Popular Functional Programming Languages in 2025?
Popular functional programming languages that enable functional programming, either exclusively or in conjunction with other paradigms, are listed below:
Haskell
First released in 1990, Haskell is a general-purpose, entirely functional programming language. Lazy evaluation and type inference are features of this statically typed language. The logician Haskell Curry is honored by the language’s name.
The Glasgow Haskell Compiler (GHC) is the primary Haskell implementation. It functions as both a native code compiler and an interpreter.
Haskell is specifically made for educational, scientific, and industrial uses. Haskell’s semantics is based on the syntax of the Miranda programming language.
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JavaScript
Because JavaScript is a procedural functional language, it allows for both functional and object-oriented programming. JavaScript is excellent for creating dynamic, intuitive webpages. You may use JavaScript in many different applications and professions. The most popular uses of this language are in front-end and back-end, and full stack web development. However, JavaScript programming abilities are also used in jobs related to gaming and mobile application development.
Java
One of the most popular functional, object-oriented, and general-purpose programming languages is Java. James Gosling created the language in 1995, and what distinguishes it from others is its WORA (Write Once, Run Anywhere) feature. This suggests that all other Java-enabled systems can use the generated Java code without the need for recompilation.
In order for any Java program or application to operate on any machine that has a Java Virtual Machine (JVM), it must first be compiled into Java bytecode. The grammar of the language is comparable to that of C and C++, two other conventional compiled functional programming languages.
Kotlin has taken the role of Java as the official language for developing Android apps. Additionally, you can mostly utilize it in data science and machine learning applications.
Erlang
Are you aware? WhatsApp is programmed using Erlang. It is a general-purpose, concurrent, functional programming language that has a garbage collector specifically designed for fault tolerance, concurrency, and transportation. Erlang is perfect for creating spread, real-time, and concurrent systems, such as telephones, database and cloud server applications, and extremely dependable systems.
Lightweight processes are used in programming languages that are process-oriented. The ability of the language to produce functions that work together with one another is what makes it so brilliant. For messaging systems like chatbots, messaging queues, and blockchain apps. Therefore, it is one of the best functional programming languages. Very responsive applications come via the language’s automatic trash collection and storage management, which have become possible on a per-process basis.
Python
Python is a functional, OOP, versatile programming language that has many uses. The language is the most general programming language, according to the August 2023 TIOBE Index.
You can extensively use this popular language because of its straightforward and simple grammar. Complex delimiters like semicolons and curly brackets have omissions in favor of simple English. Its design philosophy uses a lot of whitespace indentation to write the code easier to understand.
Additionally, Python’s standard library provides a wealth of practical tools to do a variety of tasks. For this reason, you can sometimes call it “batteries included.” With more than 300,000 Python packages, the Python Package Index (PyPI) is the official source for third-party Python microservice software.
Scala
Scala serves to build data pipelines and big data projects by fusing components of static and dynamic languages. Its static types and extensive library ecosystem help to reduce errors in complex applications. Because of its high level of compatibility with Java and the JVM, functions classified as first-class entities enable fully functional programming.
It is perfect for fusing the greatest features of dynamic and static languages. Those with prior Java experience may find Scala easier to use. Scala is a concise high-level language that combines the concepts of object-oriented and functional programming. Because Scala’s static types help to avoid issues in complex applications, JavaScript and JVM runtimes make it possible to create high-performance systems with easy access to extensive library ecosystems.
Clojure
On the Java platform, Clojure is a functional dialect of Lisp and a dynamic, one of the executable general-purpose functional programming languages. It combines a strong foundation for multithreaded programming with the interactive creation of a scripting language.
Rich Hickey created the language intending to develop a contemporary Lisp for functional programming that would allow for concurrency.
Clojure is entirely dynamic while being a compiled language. This suggests that all of Clojure’s features are runtime compatible. You can integrate S-expressions in the design of the language’s syntax. These expressions are parsed into data structures by a reader or read function before being compiled.
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F#
It is a functional programming language that is free and open-source. You can mostly use it to create powerful programs. It has a simple syntax and is the functional equivalent of the C# language. Pattern matching and asynchronous programming have become possible due to its many data types. It can modify data through functions because it adheres to an information-oriented functional programming paradigm.
Functional, declarative, and object-oriented functions are all part of the highly typed, multi-paradigm, general-purpose, function-first programming language F#. Like .NET, it is frequently a multi-platform CLI language (Common Language Infrastructure). With a few modifications, it is similar to OCaml.
It may also generate JavaScript or GPU code and belongs to the Machine learning family of languages. It offers a fair amount of tooling support.
Kotlin
Kotlin is a general-purpose, high-level, cross-platform application programming language that works flawlessly with Java. It is now the recommended and official language for developing Android apps. Kotlin has statistical syntax, and the Java Class Library is necessary for its JVM version of the standard library. It has quickly become one of the best functional programming languages in 2025.
When it comes to syntax, Kotlin is clearer and more succinct than Java. Semicolons are not always necessary as statement terminators. In many cases, the compiler can determine that a statement has concluded with just a newline.
Swift
Apple Inc. created Swift, a high-level, compiled, general-purpose programming language. Swift was created by the firm and launched in 2014 to replace Objective-C, its previous language. Objective-C’s dearth of contemporary features prompted the introduction of the new language.
Swift has some noteworthy features that solve common programming problems like the pyramid of doom and null pointer dereferencing. The language is fully compatible with Objective-C and has a simple, straightforward syntax.
Conclusion
Functional programming languages have been around for a while and are becoming more and more popular these days. Moreover, it mostly creates applications that must be extremely performant with very low latency and able to manage massive concurrent loads.
Although func programming language code frequently becomes brief and to the point, it can occasionally become difficult to grasp what the code is doing. Scala, Rust, Go, Haskell, and Erlang are a few of the most popular languages. Moreover, you can comment below your thoughts about our 10 most popular functional languages. You can also suggest more popular languages so that we can add them to our upcoming blog series.
FAQs (Frequently Asked Questions)
Is C++ Functional or OOP?
One of the numerous computer languages that supports both functional and object-oriented programming is C++.
Is Python a Functional Language?
Functional programming languages are one of the many programming styles supported by Python, a multi-paradigm programming language.
What Are The 4 Types of Programming Languages?
Procedural, object-oriented, functional, and logic programming languages are the four main categories of programming languages.
What Is Functional Language and Examples?
Under the functional programming paradigm, you can use and compose to create programs. Unlike imperative programming, it is a declarative programming approach that emphasizes “what to solve” instead of “how to solve” it.