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.

Photostream

Heian-jingu Shrine

Kyoto, Japan (2004)

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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All Content

Recent Changes

If you'd like to be notified when I post new material, subcribe to my RSS, Twitter, or Mastodon feeds. I also have a page dedicated to recent changes.


Using the cloud to scale Etsy

Thu 17 Nov 2022 09:01 EST

Etsy is a well-known marketplace for craft items. The pandemic led to a huge spike in growth, growing from 46 million buyers to 90 million buyers in two years. Etsy coped with this, with no bottlenecks in the business. One aspect of how they did this was a shift to Google cloud. Tim Cochran and Keyur Govande begin this story by describing the strategic principles that guided this effort and the incremental federated approach that they took.

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Twitter feed now cross-posts to Mastodon

Wed 02 Nov 2022 09:50 EDT

One of the main things I wanted to do with Mastodon was to replicate my twitter feed there, so that folks who would rather follow me on Mastodon could get everything. To do this, I used moa.party. You have to give it credentials to access both your Twitter and Mastodon feeds, which is a little worrisome, but my Mastodon-aware colleagues have used it without problems. It allows cross-posting in either or both directions, but I've set it up to just go from Twitter to Mastodon. It's pretty simple and seems to be working. So if you'd like to follow my twitter feed from Mastodon, you can now do so.

I'll be monitoring the follower count for the Mastodon account. If lots of people follow me on Mastodon, I'll probably do more with it. So following my Mastodon feed is vote for me to put more effort into it. But for the moment, I expect it to be a simple copy of what I post on Twitter.


Exploring Mastodon

Tue 01 Nov 2022 15:00 EDT

I've been a heavy user of Twitter over the last decade, and while Musk's purchase of Twitter hasn't got me running for the exit, it has prompted me to take a look at possible alternatives should Twitter change into something no longer worthwhile for me. The obvious alternative is for me to explore the fediverse with a Mastodon account. As I explore using Mastodon, I'll make some notes here so that others can learn from my explorations.

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Bliki: ConwaysLaw

Thu 20 Oct 2022 10:02 EDT

Pretty much all the practitioners I favor in Software Architecture are deeply suspicious of any kind of general law in the field. Good software architecture is very context-specific, analyzing trade-offs that resolve differently across a wide range of environments. But if there is one thing they all agree on, it's the importance and power of Conway's Law. Important enough to affect every system I've come across, and powerful enough that you're doomed to defeat if you try to fight it.

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