We stress our models with incremental development. Changing business requirements challenge the durability of our models. The magnitude of change is an indicator for the effectiveness of our models' ability to represent the problem domain.

At Which? we used Domain Driven Design to deliver our most recent project. In this talk, I will share those insights. I aim to cut through the jargon and give concrete, real-world examples of how we applied the principles of DDD to build a product that anticipates change.

I'm interested in different ways of programming computers, because I reckon imperative programs are far too low-level and overspecified, which is why as a species we're generally terrible at writing them. In this talk I want to encourage you to think outside of your normal programming habits; I’ll present a more abstract and declarative style called relational programming, and show you how to implement a minimal relational language in Ruby. (Dog whistle: this is μkanren.)