The evolution of software means that, over time, systems grow to be more and more complex, and require more and more developers working on them in a coordinated fashion. As the size increases, a general structure arises from there. This structure, if not well planned, can become really chaotic and difficult to work with.

The challenge of software architecture is to plan and design this structure. A well-designed architecture makes different teams able to interact with each other while at the same time having a clear understanding of their own responsibilities and their goals.

The architecture of a system should be designed in a way that day-to-day software development is possible with minimal resistance, allowing for adding features and expanding the system. The architecture in a live system is also always in flux, and can be adjusted and expanded as well, reshaping the different software elements in a deliberate and smooth fashion.

In this book we will see the different aspects of software architecture, from the top level to some of the lower-level details that support the higher view. The book is structured in four sections, covering all the different aspects in the life cycle:

• Design before writing any code
• Architectural patterns to use proven approaches
• Implementation of the design in actual code
• Ongoing operation to cover changes, and verification that it's all working as expected

During the book we will cover different techniques across all these aspects.