Design your organisation for Conway's Law
Conway's Law states that:
"Organizations which design systems are constrained to produce designs which are copies of the communication structures of these organizations."
In other words, the structure of a program or system is likely to evolve to mirror the management structure of the organisation. Even with a couple of teams working on a small project you may end up with various layers of shims and wrappers to make code written by team A interface with team B's preferred way of doing things.
The schism between Dev and Ops teams that is regularly cited in the DevOps movement is another example of Conway's Law in action. The message there is simple: get developers and operations to collaborate on common business goals (eg. frequent, reliable deployments) or else their competing priorities, poorly communicated, will cause friction that risks the business' ability to deliver on any goals. The excellent The Phoenix Project describes several potential communication gaps other than between Dev and Ops, such as between compliance and developers, and information security and operations, and tells a parable about how close cross-team collaboration avoids a series of potential disasters.
There are various solutions to the problem. In the original magazine article in which Melvin Conway introduced the idea he went on to propose a solution:
"This criterion creates problems because the need to communicate at any time depends on the system concept in effect at that time. Because the design which occurs first is almost never the best possible, the prevailing system concept may need to change. Therefore, flexibility of organization is important to effective design."
Valve's Employee Handbook describes how they have fully embraced the flexible teams approach:
"Why does your desk have wheels? Think of those wheels as a symbolic reminder that you should always be considering where you could move yourself to be more valuable. But also think of those wheels as literal wheels, because that’s what they are, and you’ll be able to actually move your desk with them."
A slightly less radical approach is to attempt to create strong but fixed communication pathways between teams. Spotify, for example, has described having chapters and guilds that encourage collaboration across team boundaries on specific issues, skills or disciplines.
You can apparently also beat Conway's Law not by improving cross-team communication but by ensuring your teams are set up to match the architecture of the technology products you want to produce. A leaked memo from a former Amazon employee that contrasts Amazon's structure with Google's mentions that Jeff Bezos mandated that:
All teams will henceforth expose their data and functionality through service interfaces. [...] Teams must communicate with each other through these interfaces.
Bezos is relying on Conway's Law to ensure the technology is structured well rather than neglecting Conway's Law and letting it create an unexpected architecture. This solution doesn't attempt to address Melvin Conway's observation that "the design which occurs first is almost never the best possible", but if you have an established or proven architecture, perhaps something that offers maintainability or security benefits, you may be able to ensure it is more closely followed by removing the flexibility to interact across the architecture boundaries you want to draw.