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.

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St Agnes, UK (2018)

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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Bliki: ExploratoryTesting

Mon 18 Nov 2019 09:51 EST

Exploratory testing is a style of testing that emphasizes a rapid cycle of learning, test design, and test execution. Rather than trying to verify that the software conforms to a pre-written test script, exploratory testing explores the characteristics of the software, raising discoveries that will then be classified as reasonable behavior or failures.

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Bliki: WaterfallProcess

Wed 13 Nov 2019 11:10 EST

In the software world, “waterfall” is commonly used to describe a style of software process, one that contrasts with the ideas of iterative, or agile styles. Like many well-known terms in software it's meaning is ill-defined and origins are obscure - but I find its essential theme is breaking down a large effort into phases based on activity.

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Continuous Delivery for Machine Learning

Tue 03 Sep 2019 09:32 EDT

Machine Learning applications are becoming popular in our industry, but teams struggle to develop, test, deploy them. At ThoughtWorks, we've gained great benefits from Continuous Delivery, so we naturally endeavored to apply this technique to our machine learning applications. Three of our senior technologists doing this work — Danilo Sato, Arif Wider and Christoph Windheuser — have written up what they've learned so far.

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Don't get locked up into avoiding lock-in

Thu 29 Aug 2019 09:49 EDT

A lot of software architects expend time and energy trying to come up with ways to avoid lock-in. Sadly many of these discussions miss important elements of how lock-in works - it's certainly not a simple binary switch. Gregor Hohpe, who's probably spent more time in such meetings than he'd like to admit, has written what I think will be an essential article on the topic. This first installment looks at the different varieties of lock-in.

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Writing Guide Pages

Tue 27 Aug 2019 10:04 EDT

In the last few months I've been working on improving the browsability of the site. This has included a graphic redesign, but the main element has been rewriting the guide pages that outline the articles on the site on a particular topic.

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Micro Frontends

Mon 10 Jun 2019 12:25 EDT

Recent years have seen an explosion of interest in the microservices architectural style, which has become popular due to its ability to allow customer-oriented teams to build and deploy software independently. A common problem such teams face, however, is how to integrate their work into the user-interface, since these are often monolithic frontend codebases.

It should be no surprise that an approach to handle this has developed that's called micro frontends, which allows teams to independently deploy their user-interface into skeletal front end application. My colleague, Cam Jackson, has been using this approach and has pulled together an article to explain further why and how to do this. It digs into the benefits and downsides of the approach, implementation approaches, and a small but detailed example.

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