Conway's Law – Effects on software architecture

A critical concept to always keep in mind while dealing with architectural designs is Conway's Law. Conway's Law is a well-known adage that postulates that the systems introduced in organizations mirror the communication pattern of the organization structure (https://www.thoughtworks.com/insights/articles/demystifying-conways-law):

Any organization that designs a system (defined broadly) will produce a design whose structure is a copy of the organization's communication structure.

– Melvin E. Conway

This means that the structure of the organization's people is replicated, either explicitly or otherwise, to form the software structure created by an organization. In a very simple example, a company that has two big departments – say, purchases and sales – will tend to create two big systems, one focused on buying and another on selling, that talk to each other, instead of other possible structures, like a system with divisions by product.

This can feel natural; after all, communication between teams is more difficult than communication within teams. Communication between teams would need to be more structured and require more active work. Communication inside a single group would be more fluid and less rigid. These elements are key for the design of a good software architecture.

The main thing for the successful application of any software architecture is that the team structure needs to follow the designed architecture quite closely. Trying to deviate too much will result in difficulties, as the tendency will be to structure, de facto, everything following group divisions. In the same way, changing the architecture of a system would likely necessitate restructuring the organization. This is a difficult and painful process, as anyone who has experienced a company reorganization will attest.

Division of responsibilities is also a key aspect. A single software element should have a clear owner, and this shouldn't be distributed across multiple teams. Different teams have different goals and focuses, which will complicate the long-term vision and create tensions.

The reverse, a single team taking ownership of multiple elements, is definitely possible but also requires careful consideration to ensure that this doesn't overstress the team.

If there's a big imbalance in the mapping of work units to teams (for example, too many work units for one team and too few for another team), it is likely that there's a problem with the architecture of the system.

As remote work becomes more common and teams increasingly become located in different parts of the world, communication is also impacted. That's why it has become very common to set up different branches to take care of different elements of the system and to use detailed APIs to overcome the physical barriers of geographical distance. Communication improvements also have an effect on the capacity for collaboration, making remote work more effective and allowing fully remote teams to work closely together on the same code base.

The recent COVID-19 crisis has greatly increased the trend of remote working, especially in software. This is resulting in more people working remotely and in better tools that are adapted to work in this way. While time zone differences are still a big barrier to communication, more and more companies and teams are learning to work effectively in full-remote mode. Remember that Conway's Law is very much dependent on the communication dependencies of organizations, but communication itself can change and improve.

Conway's Law should not be considered an impediment to overcome but a reflection of the fact that organizational structure has an impact on the structure of the software. Software architecture is tightly related to how different teams are coordinated and responsibilities are divided. It has an important human communication component.

Keeping this in mind will help you design a successful software architecture so that the communication flow is fluid at all times and you can identify problems in advance. Software architecture is, of course, closely tied to the human factor, as the architecture will ultimately be implemented and maintained by engineers.