Agenda

Go is an ideal language for building command line applications. Beyond its clean syntax and excellent standard library, it shines where it matters most: distribution. Go builds a static executable, cross-compiles effortlessly, and eliminates the need to install a runtime.

In this session we'll build a command line application from scratch. Along the way, we'll explore what makes a good CLI, discuss common design pitfalls, and tour the Go ecosystem for argument parsing, configuration, testing, shell completion, packaging, and more. You'll leave with practical patterns for building command line tools that both humans and AI agents will love to use.

This talk is about what happens when none of that is available - no internet, no cloud infrastructure, no external key management, no maintenance window. Just an operational requirement for real-time collaborative editing in an air-gapped defence environment.

Operational transformation algorithms were designed with certain network assumptions baked in. This talk covers what breaks when those assumptions don't hold, how to build a security model without external key infrastructure, and how to make deployment decisions when the target runtime is locked and non-negotiable.

Everything in this talk comes from a system that is running in production today and in an environment where failure is not an option.

I started pairing with Claude on Test-Driven Development and Behavior-Driven Development in mid January 2026. I did not know what would happen. The plan was to drop it if Claude slowed me down.

In practice, Claude can join a TDD or BDD cycle. I have used it to draft specifications, write failing tests, make them pass, and refactor afterwards. The output is good enough that I keep coming back to it.

Today I can tell you that I ship faster and that I trust more of my tests. That has less to do with Claude than you might think. A coding assistant amplifies whatever habits you bring. Bad habits get worse. Good habits compound. Mine were already test-first.

I will show examples from real production code. You will see where Claude pulls its weight and where it does not. By the end you should know what AI pairing is worth in test-first work, and what habits you need before you start.

In this session, we’ll take a real-world inspired use case: a startup company helping friends split expenses using Open Banking APIs. Using strategic design techniques such as impact mapping and event storming we’ll uncover the core business concepts and translate them directly into code. Along the way, we’ll build a modular Spring Boot application structured around business domains rather than framework layers, with modules communicating through Kafka events. But distributed systems are rarely as straightforward as they seem. 

The highlight of the session will be a live coding challenge centred on a subtle yet common pitfall: extending a business transaction with an IO operation that can fail. Together, we'll examine the solutions developers typically reach for, explore their impact on customer experience, and uncover the trade-offs hidden beneath the surface.  

We'll wrap up with a deep dive into the Transactional Outbox Pattern and see how Spring Modulith helps enforce architectural boundaries, making event-driven systems more modular, reliable and easier to evolve.