Functional Programming

An approachable, well-written, practice-oriented, academism-free guide into programming with types. How to build useful real-world type-level programs with low complexity and low risks.

Explore the event-driven architecture (EDA) in a purely functional way. Learn to design and develop distributed systems that scale. Identify common design patterns in such systems. Take your functional programming skills to the next level by joining me in developing a distributed system powered by Apache Pulsar and Fs2 streams, all in Scala 3!

Build a strong foundation in Gleam and learn how to turn its simplicity into reliable, concurrent systems. From language basics and the BEAM to OTP, web development and deployment, this practical guide uses clear explanations and runnable examples to help you build software that is safe, scalable and ready for production.

Want to use NixOS "for real" at work? Interested in learning one of the hottest emerging DevOps technologies? Jumpstart your professional career by reading this book authored by a professional user of NixOS.

Have you wondered what makes functional programming such a big deal, but haven't been able to get through any of the explanations? We wrote this book for you. Four years in the making! Phone-friendly: the code listings are easily readable without phone gymnastics. This is a small book—it took an enormous amount of effort to make it so! Also available as a Print Book.

Transform the way you think about code with Clojure. From your first expression to professional application design, The Clojure Programming Journey reveals the power of functional programming, immutability, and elegant software architecture. Build lasting skills in a language designed for simplicity, clarity, and mastery.

Python's best kept secret is its built in support for functional programming. Even better, it allows functional programming to be blended seamlessly with procedural and object oriented coding styles. This book explains what functional programming is, how Python supports it, and how you can use it to write clean, efficient and reliable code.

Learn to use R, the tidyverse collection of packages and functional programming concepts to write efficient and readable code.

Practical functional programming in Java using Vavr functional library

Everywhere you look, programming languages are gaining functional features. The problem is that it's not the individual features that make functional programmers happy, it's the way that your approach to writing software and the features work together to help you write simple code to solve interesting problems. This concise, practical ebook will help you discover why F# is such a popular language with those who have spent time learning its secrets. 

A practical book aimed for those familiar with functional programming in Scala who are yet not confident about architecting an application from scratch. Together, we will develop a purely functional application using the best libraries in the Cats ecosystem, while learning about design patterns and best practices.

Approaching PHP from a functional perspective. Yes, really. (With just a pinch of category theory.)

Tired of React runtime errors despite TypeScript? Elm guarantees zero runtime exceptions—if it compiles, it works. This practical guide shows React developers how Elm's strict functional programming approach eliminates entire classes of bugs while teaching you real FP concepts that transfer to any language. Learn the pattern that inspired Redux, discover compile-time safety that catches errors TypeScript misses, and see side-by-side code comparisons from a production codebase with 150,000+ lines of Elm. Your React knowledge is your advantage—this book meets you where you are. Why this book exists: Christian believes Elm is the fastest and most effective way for developers to truly learn functional programming—not watered-down FP patterns, but real, uncompromising functional thinking. Whether you adopt Elm professionally or not, learning it will make you a better developer in any language. This book is his way of sharing that insight with React developers who are ready to level up.