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 and 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.

Photostream

Two Ocean Lake Trail, Grand Tetons N.P., WY (2011)

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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Don't Compare Averages

Thu 24 Sep 2020 11:07 EDT

In business meetings, it's common to compare groups of numbers by comparing their averages. But doing so often hides important information in the distribution of the numbers in those groups. There are a number of data visualizations that shine a light on this information. These include strip charts, histograms, density plots, box plots, and violin plots. These are easy to produce with freely available software, working on groups as small as a dozen, or as large as thousands.

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A short review of Coup 53

Sun 30 Aug 2020 13:36 EDT

Coup 53 is a recent documentary of the American-led coup against Mohammad Mosaddegh, the leader of Iran in 1953. It's a worthwhile telling of an oft-overlooked piece of history, even if the meta-narrative that drives the documentary isn't properly examined.

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Distributed Systems Pattern: Singular Update Queue

Thu 20 Aug 2020 09:44 EDT

When the state needs to be updated by multiple concurrent clients, we need it to be safely updated with one at a time changes. Generally locks are used to protect against concurrent modifications. But if the tasks being performed are time consuming, like writing to a file, blocking all the other calling threads until the task is completed can have severe impact on overall system throughput and latency. It is important to make effective use of compute resources, while still maintaining the guarantee of one at a time execution.

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A brief review of the Kinesis Advantage2 ergonomic keyboard

Tue 18 Aug 2020 11:06 EDT

About three-and-a-half years ago I bought a Kinesis Advantage2 ergonomic keyboard. This tool isn't cheap, and it's rather unusual in its layout. But I use a keyboard all day, so I wanted one that maximized my comfort and enjoyment at my work. I've found it a worthwhile investment.

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Patterns of Distributed Systems

Tue 04 Aug 2020 10:37 EDT

Over the last few months, my colleague Unmesh Joshi has been running workshops to teach developers about distributed systems design. In this work he's been delving into many open-source distributed systems and identifying patterns. As he writes them up, he's publishing the patterns on my site.

Today he's publishing an initial narrative article that ties the first batch of patterns together, and two of these patterns: Heartbeat and Generation Clock. He has another handful of patterns close to publication that he hops to publish over the next few weeks, and more will come as he continues to develop this work.

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A Guide to Threat Modelling for Developers

Mon 18 May 2020 11:41 EDT

Threat modeling is a well-respected practice in designing secure systems. But it's often done with complicated, exhaustive upfront analysis. Jim Gumbley has spent the last few years helping ThoughtWorks teams and clients adopt a different approach, which fits in with the “little and often” agile philosophy. I'm happy that he's now written an article to share his way of working, and this first installment explains applying this incremental thinking to threat modeling.

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