Books

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.

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 125,000+ 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.

All software design is composition: the act of breaking complex problems down into smaller problems and composing those solutions. Most developers have a limited understanding of compositional techniques. It's time for that to change.

In functional programming, at the heart of input/output, failure, state, logic, and much more, lies a powerful abstraction called monad. This book provides a journey from the very first concepts, to the myriad of monads available to programmers, down to the categorical foundations.

Discover the complete world of Scala programming in one comprehensive encyclopedia. SCALAPEDIA takes you from language fundamentals to advanced functional programming, covering Cats, Cats Effect, ZIO, design patterns, architectural patterns, and performance optimization. With over 85 chapters spanning 10 major parts, this is the definitive guide for mastering Scala and building enterprise-grade applications. Whether you're starting your Scala journey or looking to deepen your expertise, SCALAPEDIA is your complete reference for modern functional programming in Scala.

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.

Stop debating code style. Start engineering code. Every developer brings personal preferences. Every AI tool channels different training examples. The result? Inconsistent codebases, endless code reviews, and technical debt that compounds silently. Java Backend Coding Technology introduces a radical idea: reduce the space of valid choices until there's essentially one good way to do most things. Not through rigid frameworks, but through a small set of patterns that make structure predictable, refactoring mechanical, and business logic visible. The code you write, your teammate writes, and your AI assistant generates will look the same -- because the patterns leave no room for subjective variation.

Write code that you can understand without holding the entire system in your head. This book shows you how Java's modern functional features—records, sealed types, lambdas, streams—combine into a powerful approach to design. You'll learn: • How to eliminate race conditions without synchronized blocks • How to write tests that test business logic, not mock frameworks • How to compose complex behaviors from simple, reusable functions • How to manage deeply nested immutable data without boilerplate • How to adopt functional patterns incrementally in existing codebases Written for working developers. Filled with production-ready code examples.

Discover the pure functional side of HTTP API programming in Scala.

After reading this book, you will understand everything in FP. Prove that your application's business logic satisfies the laws for free Tambara profunctor lens over a holographic co-product monoidal category (whatever that means), and implement the necessary code in Scala? Will be no problem for you.

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. 

Practical functional programming in Java using Vavr functional library

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.

Discover why functional languages, such as Elixir, are ideally suited to building applications following the command query responsibility segregation and event sourcing (CQRS/ES) pattern. Learn how to implement this architecture in a Phoenix web application to build an exemplary Medium.com clone.