Conway's Law: The Hidden Force Shaping Your Software Architecture

Have you ever wondered why your carefully designed software architecture keeps drifting away from your initial vision? Or why your codebase seems to mirror your team structure more than the actual problem you’re trying to solve?

If you’re nodding your head, you’re not alone. These puzzling situations are often the result of a subtle but powerful force in software development: Conway’s Law.

What’s Really Going On?

Think about your last big project. Did you notice any of these signs?

• Features that should be unified are spread across multiple components.
• Duplicate code or functionality in different parts of the system.
• Integration points that are more complex than they need to be.
• Architectural decisions that seem to reflect team boundaries rather than technical needs.

If these sound familiar, Conway’s Law might be at play in your organization.

So What Exactly is Conway’s Law?

Conway’s Law, named after programmer Melvin Conway in 1967, states:

“Organizations which design systems are constrained to produce designs which are copies of the communication structures of these organizations.”

In simpler terms: Your software architecture will inevitably reflect how your teams communicate and are organized.

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Organization Structure                 System Architecture
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----------------------                 -------------------
3

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+-------------+                        +-------------+
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|   Team A    |                        | Component A |
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+-------------+                        +-------------+
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        |                                      |
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        |                                      |
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+-------------+                        +-------------+
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|   Team B    |                        | Component B |
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+-------------+                        +-------------+
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        |                                      |
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        |                                      |
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+-------------+                        +-------------+
15
|   Team C    |                        | Component C |
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+-------------+                        +-------------+

Notice how the system architecture mirrors the organization structure. Each team ends up creating a corresponding component, even if a different architecture might be more efficient.

The Hidden Dynamic: Path of Least Resistance

Here’s the kicker that often goes unnoticed: Teams will typically choose to solve problems themselves rather than reach out to other teams. They’ll often accept a suboptimal architecture if it means avoiding the hassle of cross-team coordination.

This preference for internal solutions can lead to:

• Duplicated functionality
• Convoluted workarounds
• Inconsistent approaches to similar problems across the system

Here’s how this often plays out:

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Ideal Flow                             Actual Flow
2
----------                             -----------
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+-------+    +-------+                 +-------+
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|Team A |<-->|Team B |                 |Team A |
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+-------+    +-------+                 +-------+
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    ^            ^                         |
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    |            |                         |
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    v            v                         v
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+-------+    +-------+                 +-------+
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|Team C |<-->|Team D |                 |Team C |
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+-------+    +-------+                 +-------+
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                                            |
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                                            |
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                                            v
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                                        +-------+
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                                        |Team B |
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                                        +-------+
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                                            |
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                                            |
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                                            v
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                                        +-------+
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                                        |Team D |
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                                        +-------+

In the ideal flow, teams collaborate directly. In the actual flow, Team A might implement a suboptimal solution to avoid coordinating with Team B, passing the problem down the line.

Why Should You Care?

Understanding Conway’s Law isn’t just an academic exercise. It’s a practical tool that can help you:

• Anticipate architectural challenges based on team structure.
• Make informed decisions about organizing your development teams.
• Avoid common pitfalls in system design that stem from organizational issues.

Working With (or Around) Conway’s Law

Knowing about Conway’s Law is half the battle. Here’s how you can use this knowledge:

1. Intentional Team Design: Structure your teams based on the architecture you want, not the other way around.
2. Fight for Clear Boundaries: Ensure each team has a well-defined domain or feature set. Clear boundaries prevent architectural shortcuts that can become painful later.
3. Cross-Functional Teams: Build teams that can deliver end-to-end features. This reduces the need for complex inter-team dependencies.
4. Regular Architecture Reviews: Step back and assess: Is your system structure serving your needs, or just reflecting your org chart?
5. Encourage Cross-Team Communication: The more your teams talk to each other, the more integrated your systems are likely to be.

Here’s how you might restructure teams to achieve a desired architecture:

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Before                                 After
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------                                 -----
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+----------+                           +-----------------+
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|Frontend  |                           |Feature Team 1   |
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|Team      |                           |(UI + Backend)   |
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+----------+                           +-----------------+
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      |                                          |
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      |                                          |
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+----------+                           +-----------------+
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|Backend   |                           |Feature Team 2   |
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|Team      |                           |(UI + Backend)   |
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+----------+                           +-----------------+
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      |                                          |
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      |                                          |
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+----------+                           +-----------------+
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|Database  |                           |Platform Team    |
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|Team      |                           |(Shared Services)|
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+----------+                           +-----------------+

By restructuring into cross-functional feature teams, you can encourage a more integrated architecture that aligns with product features rather than technical layers.

Here’s a quick example of how clear boundaries can help:

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# Before: Fuzzy boundaries leading to duplication
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class FrontendTeam:
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    def build_ui(self):
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        pass
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    def validate_user_input(self):  # Duplicate logic
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        pass
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class BackendTeam:
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    def create_api(self):
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        pass
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    def validate_user_input(self):  # Duplicate logic
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        pass
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# After: Clear boundaries and responsibilities
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class UserInterfaceTeam:
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    def build_ui(self):
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        pass
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    def collect_user_input(self):
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        pass
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class BusinessLogicTeam:
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    def validate_input(self):
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        pass
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    def process_data(self):
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        pass
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class DataAccessTeam:
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    def store_data(self):
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        pass
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    def retrieve_data(self):
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        pass

Conway’s Law isn’t a rule set in stone, but ignoring it is like swimming against the current. By understanding how your organizational structure influences your system architecture, you can make more informed decisions about both.

Remember, great software isn’t just about code—it’s about the people and structures that create it. Sometimes, the key to solving a persistent architectural issue might not be in your codebase, but in your org chart.