A common saying by software architects is “that’s an implementation detail”. All too often we treat software architecture and implementation as two separate things, where implementation is something that happens once a software architecture is defined. In fact, it’s the other way around: software architecture should be viewed as a first draft, where implementation reveals more details and refinements. In this provocative keynote Mark Richards discusses the intersection of architecture and implementation, and how the two must be in constant alignment to achieve success. Through real-world examples, he shows how implementation can get out of alignment with the architecture, causing the system to fail to achieve its desired goals. He then shows some techniques and tools to help ensure alignment between architecture and implementation.