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Top 16 Functional Programming Languages To Know


November 30, 2021


March 26th, 2024

Functional Programming Languages

‘Known yet unknown’ is one of the biggest ironies of technological trends. Trends can change the entire software development world in just a few days. Why are we talking about this? Have you heard the term’ Functional Programming’? You might say it’s trending these days. Yes, functional programming has been around for the last 60 years, but it is more like a ‘known yet unknown’ thing in the development world. Things are changing, and every developer seems excited to learn, use, and leverage it to quickly create modern, secure, and valuable products.

Let’s proceed with the introduction to functional programming. In this blog post, we will also discuss the top 16 functional programming languages that are popular and used by developers worldwide.

What Is A Functional Programming Language?

Functional programming is a programming paradigm. A paradigm is generally a way, a model, or a pattern that solves a particular problem in computer science.

Taking this definition to the next level, functional programming involves writing code in pure functions. It is a declarative programming paradigm in which function definitions are trees of expression that map values to other values. This is opposite to the imperative paradigm, in which the sequence of statements can update the program’s running state.

What Is Functional Programming?

, functions are instructions grouped to achieve a specific outcome. Here, pure functions are given more importance as they are not allowed to interact with outside elements and always return the same output when given the same input.

Pure functions are not allowed to change their state, which is precisely opposite to the OOP, where any method can mutate the state of objects. Pure functions are also best for concurrency, as no shared state exists between functions.

Functional programming is remarkable for data analysis and machine learning. Programmers are falling in love with it because of its powerful features, such as no nulls, higher-order functions, exceptions for error handling, immutable data structures, pattern matching, and function composition operators.

Advantages Of Functional Programming:

Developers admire some of the benefits of functional programming.

  • Shorter code
  • Easy debugging
  • Modular
  • Parallel programming
  • Increased maintainability
  • Code readability

Many functional programming languages are used today in many industries. Many other programming languages support functional programming or implement such features. Functional programming is widely used in specific domains such as the web, statistics, financial analysis, machine learning, etc.

Functional Programming Languages: Best Functional Programming Languages To Learn

Here is the list of the most popular functional programming languages and languages that support programming in functional style or have functional and OOP capabilities.

  • Elixir
  • Erlang
  • Common Lisp
  • Haskell
  • F#
  • Clojure
  • Elm
  • Racket
  • OCaml
  • Idris
  • PureScript
  • Wolfram
  • Scala
  • Python
  • Kotlin
  • JavaScript

Let’s explore the list of functional programming languages in detail.


Elixir is the most popular programming language in the world. It is a functional, general-purpose, and concurrent language that runs on the BEAM virtual machine. It is famous for its suitability for building low-latency, fault-tolerant, and distributed applications.

Elixir is built on top of Erlang and uses features of Erlang, Ruby, and Clojure to become a high-concurrency and low-latency programming language. It is used by world-recognized companies that serve millions of people concurrently, such as Discord, PagerDuty, Pinterest, Bleacher Report, Inverse, The Outline, and so on. It was created by José Valim, whose goal was to make a language that can be used for large-scale sites and apps.

Because of its capabilities, Elixir is designed to handle large data volumes quickly. It is a very pragmatic language mainly used in the telecommunication, eCommerce, and finance industries. Phoenix is a development framework written in Elixir that is popular for its excellent performance.

It is superior for reliability and concurrency as it builds on Erlang. The community and the core Elixir team are putting their best efforts into the Elixir ecosystem, a combination of high-quality libraries, forums, and skilled professionals.

It is a great language to start learning functional programming; try it!


Do you know? Erlang is used to code WhatsApp. It is a general-purpose, concurrent, functional programming language and garbage-collected runtime system designed explicitly for concurrency, distribution, and fault tolerance. Erlang is suitable for building distributed, real-time, and concurrent systems such as telecommunications, database applications, servers, and highly available systems.

Erlang was originally proprietary software used in Ericsson and developed by Joe Armstrong, Robert Virding, and Make Williams in 1986. It is used interchangeably with Erlang/OTP (Open Telecom Platform), a collection of useful libraries, tools, and middleware written in Erlang. It is an integral part of the Erlang open-source distribution.

It is used by several extremely scalable and large systems, such as Facebook, the AXD301 ATM switch, Gambit Research, RabbitMQ, Wavenet, AdRoll, Bluetab Solutions, Samsung, Goldman Sachs, BT Mobile, Corelatus, Netkit Solutions, Mitel, RAD, and many others.

Erlang is also used in many industry domains, including fintech, healthcare, automotive, IoT, gaming, blockchain, and telecommunications.

Common Lisp

Common Lisp is a dialect of the Lisp programming language. It is a general-purpose, dynamic, and multi-paradigm language that supports a combination of procedural, functional, and object-oriented programming styles. Lisp is one of the oldest programming languages, and many dialects of Lisphave existed over time.

Being one of the oldest programming languages, Lisp established many ideas in software development. The best-known general-purpose Lisp dialects are Racket, Common Lisp, Scheme, and Clojure.

It supports first-class functions and offers evolutionary and incremental software development. It is widely used in some excellent software and systems, such as ITA Software, London Tube, Mirai, PWGL, Boeing, Airbus, Yahoo, Grammarly, NASA, Microsoft, and many others.

Common Lisp is mainly used to develop research applications, prototyping, and AI apps.


Haskell is considered the ‘mother’ of all functional programming languages. Haskell is a general-purpose, statistically typed, and purely functional programming language offering type inference and lazy evaluation. It is older than Java and became a pathfinder for many advanced features in programming languages.

It is widely used in academia, research, and industrial applications. Haskell functions have no side effects as it is a purely functional language. It offers lazy evaluation, lambda expressions, pattern matching, type classes, type polymorphism, and list comprehension.

Haskell’s notable applications include several world-known systems such as GHC, Agda, Pandoc, Cryptol, Cardano Blockchain platform, Target, Pugs, Xmonad, Bluespec, Linspire, and others. Haskell is a great choice to start exploring what functional programming is. It is mainly preferred for academics and research.


F# is a general-purpose, functional-first, strongly-typed, and multi-paradigm programming language that consists of functional, imperative, and object-oriented methods. It is often a cross-platform (Common Language Infrastructure) CLI language. NET. It is similar to OCaml with few differences.

It is a member of the ML language family and can also generate JavaScript and GPU code. It has excellent tooling support, an open-source community, and a rich ecosystem backed by Microsoft and The F# Software Foundation. It is used in various apps, from web APIs to data manipulation, data science, machine learning, and interactive programming apps.

It offers functional-first features such as type inference, first-class functions, pattern matching, and object support. F# is an excellent fit for data science and machine learning apps as it is robust, performant, and fast language.


Clojure is a popular dynamic and functional dialect of the Lisp programming language on the Java platform. It features immutable and persistent data structures and allows developers to manage identity and states explicitly, which gives developers a significant advantage in creating concurrent and fast programs.

Rich Hickey created the Clojure language to create a modern Lisp for functional programming. It supports functions as first-class objects, a macro system, and a read-eval-print loop. It also supports lazy sequences, recursion, a reactive agent system, and higher-order functions. Clojure’s primary platform is Java, but many other target implementations exist.

It is used by many world-recognized companies, including Walmart, Chartbeat, Netflix, Puppet, Circle CI, LinkedIn, Salesforce, Cisco, Boeing, ThoughtWorks, Atlassian, Room Key, Pisano, GO-JEK, Freshcode, LendUp, and so on.


Elm is a domain-specific programming language used explicitly for building web browser-based GUIs. It is a purely functional language and offers usability, simplicity, performance, and robustness. Elm compiles to JavaScript. Some noticeable features of this language include no runtime exceptions, easy refactoring, friendly error messages, excellent performance, a module system, static typing, and interoperability with HTML, CSS, and JavaScript.

It was created by Evan Czaplicki in 2012. As a functional language, it supports anonymous functions, functions as arguments, and can return functions. It is widely used for front-end web development. Some of the limitations of Elm include a large amount of boilerplate code, no active community, and no support for higher-kindred polymorphism and type classes. Elm is used by many companies in production, such as Watermark, Basiq, Actcast, GlobalWebIndex, Day One, EXR, Microsoft, Emirates, treefin, NoRedInk, thoughtbot, and so on.


Racket is a dialect of Lisp and a descendant of Scheme. It is a modern, general-purpose, multi-paradigm programming language and a multiplatform distribution that includes the language, standard library, IDE, development tools, and additional languages.

Racket is good for exploring ideas and rapid prototyping. It is also used in commercial projects and web applications. DrRacket is a self-hosted IDE widely used in computer science courses to teach Scheme and Racket. Racket is mainly used for scripting, computer science education, and research.

The core Racket language is famous for its massive macro system that enables building domain-specific languages and language constructs.


Ocaml, Objective Caml is a general-purpose, multi-paradigm language that extends the Caml dialect of ML with object-oriented features. It is a free and open-source project managed and maintained by the French Institute for Research in Computer Science and Automation.

OCaml combines functional, imperative, and object-oriented programming under an ML-like type system. It offers features such as a static type system, type inference, pattern matching, parametric polymorphism, exception handling, and tail recursion.

Some globally popular companies use OCaml in their production environments, such as Bloomberg, Facebook, Jane Street Capital, GeneWeb, Flow, the Hack Programming language compiler, Citrix Systems, etc.

It is as old as Java but has a small community and few learning resources. You won’t find great libraries and framework support. This makes OCaml less popular than other functional languages.


Idris is yet another purely functional programming language. It offers many features borrowed from mainstream functional programming and proof assistants. The key features of Idris include dependent types, lazy evaluation, and totality checkers. It encourages Type-Driven Development, where types are tools for creating programs.

Type-driven development is a notable feature of Idris and helps developers improve the program’s performance and accuracy. It prioritizes the management of side effects and support for embedded domain-specific languages. The code written in Idris is easy to maintain and test.

Idris is known for its state-of-the-art type system, which makes it unique.


PureScript is a strongly-typed and purely functional programming language that compiles JavaScript. Syntactically, it is similar to Haskell. It also has features such as persistent data structures, higher kinded types, pattern matching, type classes, functional dependencies, and higher-rank polymorphism.

It was designed by Phil Freeman in 2013. It is widely used to develop web applications, servers, and more. It has an active community and excellent tooling, making this language more accessible to pick for beginners.


Wolfram language is a general, multi-paradigm programming language developed by Wolfram Research. It emphasizes functional programming, rule-based programming, and symbolic computation. It was a part of the initial version of Mathematica in 1988.

It is majorly used for real-world data computing, algorithmically-oriented programming, reactional programming, rapid concept deployment, analytics, IoT, education apps, legacy modernization, and multiplatform deployments. Wolfram is vital in developing new research, education, and science ideas.


Scala is not functional, but it supports functional and object-oriented programming. We consider Scala for functional programming because it combines OOP and functional programming in one concise, high-level language.

Scala is a modern, multi-paradigm programming language on the Java Virtual Machine (JVM). It integrates features of object-oriented and functional languages. Scala is statically typed, extensible, and fully interoperable with Java.

Considering the functional level context, it supports many features of Scheme, Standard ML, and Haskell, including lazy evaluation, higher-order types, immutability, pattern matching, and type system supporting algebraic data types, raw strings, and optional parameters. It is used by prominent companies around the world, such as Foursquare, The New York Times, Airbnb, SoundCloud, Verizon, Morgan Stanley, Firebase, LinkedIn, Twitter, MeetUp, Coursera, Apple, Walmart, Databricks, and many others.

Scala has received many accolades, such as being the most popular programming language, an alternative language of the JVM, and a JVM-based popular programming language.


Python doesn’t need any introduction. It is not a functional language but supports coding in a functional, declarative style. Its design promotes functional programming through functions, generator expressions, list comprehensions, sets, and dictionaries. Haskell and Standard ML inspire it.

It embraces a “there should be one – and preferably only one obvious way to do it” design philosophy. It is one of the popular programming languages used for various apps and systems. Python community is the largest one and is considered its greatest strength. It is more commonly used in AI, machine learning apps, a scripting language for web applications, scientific computing, and the information security industry, and many components are written in Python.

Amazon, Instagram, NASA, Google, Yahoo, Wikipedia, Reddit, ITA, Spotify – some organizations that use Python.


Kotlin is a cross-platform, statically typed, and general-purpose programming language, but it can also be used to code in functional styles. It is an excellent choice for exploring functional programming as it offers first-class support for features such as function types and lambdas, higher-order functions, and more.

It is concise, type-safe, and faster. Kotlin is more straightforward as it is 100% interoperable with the Java programming language. Kotlin is used for server-side and client-side web apps, desktop apps, and native development. It is also supported as a first-class language on the Android platform. Many companies, such as Square, Pinterest, Basecamp, Corda, etc., use it.

Kotlin has a vibrant and active community with support forums, events, and resources.


JavaScript is primarily scripting and not widely known as a functional language, but it does support functional elements.

JS is high-level, often just-in-time compiled, and multi-paradigm. It supports dynamic typing, first-class functions, and prototype-based object orientation. JavaScript, along with CSS and HTML, is one of the core technologies of the World Wide Web. It supports event-driven, functional, and imperative programming styles as a multi-paradigm language.

It has much in common with Scheme. JavaScript is used almost everywhere in every app and on the web.

Best Functional Programming Language: Talk Of The Town

It’s in trend.

Yes, functional programming allows developers to solve complex problems more simply. It improves the maintainability, accuracy, and modularity of the code. It differs from the OOP but aims for performance, stability, and reliability.

While we are not saying OOP should not be used or entirely replaced by FP, combining both is required to build a modern, scalable, and reliable system. Based on your requirements, you can choose the paradigm of your choice. Functional programming has some benefits to consider when building a new software product.

Do you know any functional programming language?

What functional programming language will you pick to start exploring functional programming?

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