What will save us from software complexity? Microservices architectures? Immutable data? Functional languages? Event streaming? These may seem like disparate solutions, but they’re all connected, They’re all striving to solve the same fundamental problem: Side effects.

Side effects are one of the most insidious causes of software complexity, and yet we’re barely aware of them. And the attempts to tackle side effects have produced some of the most interesting developments in software development in the past decade, yet as an industry we’re barely aware of the fundamental pattern tying everything together. Let’s fix that.

Join me to understand what side effects are and why they matter. You’ll learn to spot them in your own code. You’ll see how they sneak into our tests, our APIs and our systems’ designs and make everything harder. Then we’ll look at our industry’s many solutions to side effects. You’ll see why immutable data structures are appearing in every language; why we invented OO and why it might get replaced with FP. And we’ll see what it all means for the larger designs of microservices, data processing and event systems.

Side effects are a hologram - put the right light on them and you can see a whole picture of modern computing emerging. Take a look and you’ll see the nice things the future could hold.