XP is an approach that helps us to deliver valuable software iteratively, to apply it we need to setup our teams to make releasing change to customers as easy as possible. We avoid waiting around for individual team members to make changes, by applying classic XP practices -- Collective Code Ownership and Pair Programming. Each pair of developers is free to change any code that they need to without anyone vetting their changes, they ensure that all tests pass and keep code relatively clean by refactoring as they go. We share knowledge across the team by rotating pairs daily. If a pair runs into difficult decisions regarding design choices, they can call for a huddle with their team mates, sitting together in an open workspace means that's quick to do. This XP way of developing code is liberating as we can easily make changes in the right place rather than working around organisational barriers. It can be also be humbling, as our code is often improved by other developers as they pass through.

To work this way, we find it helps to build teams of extremely capable developers who can work on any area of the codebase rather than hiring a mix of frontend/backend/DBA specialists. Developers who only know enough to work in a single layer of the codebase limit who's available to pair on the piece of work which is most valuable to pick up next. At Unruly, we only hire “full-stack” developers, this gives us confidence that any pair of developers can work on any area of the codebase (within the products that their team is responsible for) without experiencing hand-offs and delays waiting for developers with a different skill set. It also helps avoid some of the friction that can spark due to single-layer thinking.

To make collective code ownership easier, some product teams select a homogeneous stack such as Clojure with ClojureScript or JavaScript all the way down using Node. At Unruly, our developers need to be fluent in JavaScript and Java with a smattering of Scala. Full-stack developers are bright people who can keep pace with developments in multiple languages and frameworks rather than immersing themselves in a single core development language. Being a full-stack developer is more than being able to write code in different languages, you have to understand idioms and patterns for UI, middleware, database realms too.

Being a full-stack developer is also much more than becoming a polyglot programmer. Laurence Gellert’s explains in his blog that there’s a greater breadth of skills that a “full-stack” developer needs. You’ll need to appreciate the environment that your live system runs within and have the technical chops to be at home with making environment changes. You'll also need to broaden your horizons beyond thinking about code and get to grips with developing a fuller understanding of the business you work in! Michael Feathers recently gave a talk in London where he used the term “Full Spectrum Developer” which neatly captures the idea that there's much more than being able to work across different software layers in a given architecture.


As the software craftsmanship movement has brought to the fore, serious developers need to take personal responsibility for improving their skills. Of course, becoming a full-stack developer is more than reading the odd business book in your spare time and writing toy programs in obscure languages when you get home from a long day at work. You can also get together with likeminded developers on a regular basis to hone your skills through Code & Coffee sessions outside work and work on pet projects like building games and mobile apps at home. But in my opinion, this only scratches the surface - you will only get to grips with being a full-spectrum developer by working in an environment that allows you to get your hands dirty across the full stack and interact directly with users and stakeholders. Typically these are startups or small companies that practice agile software development. If you take a look at our current open roles, you’ll see they’re much broader that you’d typically find in a large corporation.

As an agile coach working with product development teams at Unruly, my focus is on how we can support developers to expand their horizons, to gain a better understanding of our business and how they can help figure out the most valuable software to deliver iteratively. Our developers take responsibility for researching different strands of product development and identify the most valuable ideas to take through to implementation (I'll write-up more about how we do this in another post soon).

We also recognise that build learning time into our work week is essential for developers to stay abreast of new tools and frameworks. All of our developers get one day per week to dabble and learn new technologies — see my previous post about Gold Cards. We recognise that industry conferences can be places where you hear about new trends so developers get three days and an annual allowance to spend on attending any conference they feel is relevant to the personal development at work. Our developers also take turns running weekly coding dojos (during work time not through their lunch) to get hands-on practice time with new languages such as Go, Scala, Rust and mobile phone application development. Developers get the opportunity to share what they learned to other teams through lightning talks and this gives them practice in presenting too. All of these things are ways that organizations can support developers in broadening their horizons while at work rather than eating into their early mornings and evenings.

There are a few things for developers to weigh up when considering whether to specialise deeply or broaden their horizons. What do you sacrifice when following one path versus rewards to be gained? The main reward for full-spectrum developers is building greater confidence to dive into different technologies; you may spend less time writing code but become more able to deliver end-to-end solutions that hit the spot. As generalists, you likely have a wider choice of companies to work at and are more resilient to industry trends. As specialists, you gain the pleasure of total immersion in a particular sphere of software while you build tolerance to the frustrations of waiting around for others to do their bit. It's up to you!