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This book is about building a complex system in Clojure and ClojureScript. It started out as a blog series about my BirdWatch application, a side project for reasoning about a live stream of tweets coming in from the Twitter Streaming API and visualized in a web application that is written in ClojureScript.

In the book, we will follow the data and watch how it is transformed in different parts of the application until it finally triggers the user interface to change within a few hundred milliseconds after a tweet has been tweeted.

The price for this book will increase as the writing progresses.

Feedback during the writing process is much appreciated. There's a Google Group for this purpose.

Only major new releases will be announced by email. Please follow me on Twitter to be informed about more frequent updates: @matthiasnehlsen. Or, if you want to know what I'm working on at any moment in time, follow me on GitHub. The book is on there as well, just like the project that I am writing the book about.

Cheers, Matthias

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Kick off your book project in 3 hours! Live workshop on Zoom. You’ll leave with a real book project, progress on your first chapter, and a clear plan to keep going. Saturday, May 16, 2026. Learn more…

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