Software development is a young profession, and we are still learning the techniques and building the tools to do it effectively. I've been involved in this activity for over three decades and in the last two I've been writing on this website about patterns and practices that make it easier to build useful software. The site began as a place to put my own writing, but I also use it to publish articles by my colleagues.

In 2000, I joined Thoughtworks, where my role is to learn about the techniques that we've learned to deliver software for our clients, and pass these techniques on to the wider software industry. As this site has developed into a respected platform on software development, I've edited and published articles by my colleagues, both ThoughtWorkers and others, to help useful writing reach a wider audience.

photo of Martin Fowler

photo: Christopher Ferguson

Martin Fowler

A website on building software effectively

If there's a theme that runs through my work and writing on this site, it's the interplay between the shift towards agile thinking and the technical patterns and practices that make agile software development practical. While specifics of technology change rapidly in our profession, fundamental practices and patterns are more stable. So writing about these allows me to have articles on this site that are several years old but still as relevant as when they were written.

As software becomes more critical to modern business, software needs to be able to react quickly to changes, allowing new features to be be conceived, developed and put into production rapidly. The techniques of agile software development began in the 1990s and became steadily more popular in the last decade. They focus on a flexible approach to planning, which allows software products to change direction as the users' needs change and as product managers learn more about how to make their users effective. While widely accepted now, agile approaches are not easy, requiring significant skills for a team, but more importantly a culture of open collaboration both within the team and with a team's partners.

This need to respond fluently to changes has an important impact upon the architecture of a software system. The software needs to be built in such a way that it is able to adapt to unexpected changes in features. One of the most important ways to do this is to write clear code, making it easy to understand what the program is supposed to do. This code should be divided into modules which allow developers to understand only the parts of the system they need to make a change. This production code should be supported with automated tests that can detect any errors made when making a change while providing examples of how internal structures are used. Large and complex software efforts may find the microservices architectural style helps teams deploy software with less entangling dependencies.

Creating software that has a good architecture isn't something that can be done first time. Like good prose, it needs regular revisions as programmers learn more about what the product needs to do and how best to design the product to achieve its goals. Refactoring is an essential technique to allow a program to be changed safely. It consists of making small changes that don't alter the observable behavior of the software. By combining lots of small changes, developers can revise the software's structure supporting significant modifications that weren't planned when the system was first conceived.

Software that runs only on a developer's machine isn't providing value to the customers of the software. Traditionally releasing software has been a long and complicated process, one that hinders the need to evolve software quickly. Continuous Delivery uses automation and collaborative workflows to remove this bottleneck, allowing teams to release software as often as the customers demand. For Continuous Delivery to be possible, we need to build in a solid foundation of Testing, with a range of automated tests that can give us confidence that our changes haven't introduced any bugs. This leads us to integrate testing into programming, which can act to improve our architecture.

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Bromley Mtn, VT (2021)

Data Management

There are many kinds of software out there, the kind I'm primarily engaged is Enterprise Applications. One of the enduring problems we need to tackle in this world is data management. The aspects of data managment I've focused on here are how to migrate data stores as their applications respond to changing needs, coping with different contexts across a large enterprise, the role of NoSQL databases, and the broader issues of coping with data that is both Big and Messy.

Domain-Specific Languages

A common problem in complex software systems is how to capture complicated domain logic in a way that programmers can both easily manipulate and also easily communicate to domain experts. Domain-Specific Languages (DSLs) create a custom language for a particular problem, either with custom parsers or by conventions within a host language.

Books

I've written seven books on software development, including Refactoring, Patterns of Enterprise Application Architecture, and UML Distilled. I'm also the editor of a signature series for Addison-Wesley that includes five jolt award winners.

My Books Page...

Conference Talks

I'm often asked to give talks at conferences, from which I've inferred that I'm a pretty good speaker - which is ironic since I really hate giving talks. You can form your own opinion of my talks by watching videos of some my conference talks.

My Videos Page...

Board Games

I've long been a fan of board games, I enjoy a game that fully occupies my mind, clearing out all the serious thoughts for a bit, while enjoying the company of good friends. Modern board games saw dramatic improvement in the 1990's with the rise of Eurogames, and I expect many people would be surprised if they haven't tried any of this new generation. I also appear regularly on Heavy Cardboard.

My Board Games page...

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You Can't Buy Integration

Tue 30 Nov 2021 09:45 EST

“Build versus buy” decisions are everywhere today, and rightly so. Building software is risky and expensive, and software product companies can spread that risk and expense across multiple customers. But my colleague Brandon Byars argues that the kinds of tools that are available to buy for systems integration are not products that directly solve a business problem.

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Scaling the Practice of Architecture, Conversationally

Tue 30 Nov 2021 09:43 EST

Like many modern software architects, Andrew Harmel-Law struggles with the need to scale architectural thinking to larger organizations while allowing teams to be as autonomous as possible. The approach he's currently using is the "Advice Process", that encourages and supports these teams to be engaged in broader architectural decision making. In this first installment, Andrew describes this advice process, later installments will dig into four supporting elements that help make it work.

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The strong and weak forces of architecture

Wed 10 Nov 2021 13:10 EST

Good technical design decisions are very dependent on context. Teams that regularly work together on common goals are able to communicate regularly and negotiate changes quickly. These teams exhibit a strong force of alignment, and can make technology and design decisions that harness that strong force. As we zoom out in a larger organisation an increasingly weak force exists between teams and divisions that work independently and have less frequent collaboration. Recognising the differences in these strong and weak forces allows us to make better decisions and give better guidance for each level, allowing for more empowered teams that can move faster.

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Bliki: DefaultTrialRetire

Wed 10 Nov 2021 13:04 EST

Within each normal-sized team, limit the choice of alternatives for any class of technology to three. These are: the current sensible default, the one we're experimenting with as a trial, and the one that we hate and want to retire.

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Compliance in a DevOps Culture

Tue 02 Nov 2021 09:39 EDT

Integrating the necessary security controls and audit capabilities to satisfy compliance requirements within a DevOps culture can capitalize on CI/CD pipeline automation, but presents unique challenges as an organization scales. Understanding the second order implications and unintended consequences caused by the chosen implementation is key to building an effective, secure, and scalable solution. My colleague Carl Nygard describes how to think of these choices through a series of four patterns for handling compliance.

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Foreword to "The Art of Agile Development"

Tue 26 Oct 2021 10:24 EDT

James Shore has revised his book "The Art of Agile Development". I'm pleased to write a foreword for this book as it is solid guide to learning how to get past faux-agile and develop the skills you need to get the benefits of the agile way of work.

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