Simon Brown on C4 Model: Misconceptions, Misuses and Mistakes

C4 Model: Recent Insights from Simon Brown

TLDR: Simon Brown, creator of the C4 model, shares critical insights about common misconceptions, misuses, and mistakes when applying this architectural documentation approach through a DDD Europe talk and a comprehensive Reddit AMA.

Summary:

The C4 model has become one of the most widely adopted approaches for documenting software architecture, yet its creator Simon Brown identifies persistent patterns of misunderstanding and misapplication. These recent materials—a talk from DDD Europe and a detailed Reddit AMA—represent essential guidance directly from the source on how to properly use this documentation tool.

The DDD Europe talk specifically addresses "misconceptions, misuses and mistakes" with the C4 model. This is particularly valuable because it tackles real-world problems teams encounter when adopting C4. The model's simplicity is both its strength and its weakness—it's easy to start using, but that ease of adoption can lead to applying it incorrectly. Brown's talk likely addresses issues like confusing abstraction levels, over-documenting trivial systems, or treating C4 as a rigid framework rather than a flexible thinking tool.

The Reddit AMA provides an even more direct channel for understanding Brown's current thinking about C4. Community questions in AMAs often surface practical concerns that don't make it into formal presentations—edge cases, integration with specific tools, how to handle legacy systems, when to skip levels of the model, and how to convince teams to adopt architectural documentation practices. These pragmatic concerns are where theoretical models either prove their worth or reveal their limitations.

What's being avoided here is the question of when architectural documentation itself becomes counter-productive. C4 is a tool for communication, but communication has costs. Creating diagrams takes time. Maintaining them as systems evolve takes discipline. Using them effectively requires shared understanding across teams. If the documentation isn't actively helping decisions or onboarding, it's just ceremony. Brown's emphasis on "misuses and mistakes" suggests he's aware of this tension—the model works when applied thoughtfully, not when treated as mandatory process.

For architects and teams, the timing of these materials is relevant. If you're already using C4, they provide calibration—an opportunity to check if you've drifted into anti-patterns. If you're considering adoption, they front-load the lessons that typically come from painful trial and error. The combination of structured talk and free-form AMA covers both conceptual foundations and implementation details.

The connection to Emmett (mentioned in the newsletter) suggests active development in tooling or practices around C4. This is important because C4's success depends partly on reducing the friction of creating and maintaining diagrams. If updating documentation is painful, it won't happen. Tools that integrate C4 with existing development workflows—code generation, automated diagram updates, version control integration—address the maintenance burden that causes documentation to rot.

Key takeaways:

• Direct insights from C4's creator address common real-world misapplications rather than just theoretical usage
• The Reddit AMA format surfaces practical edge cases and implementation concerns that formal presentations skip
• Architectural documentation is only valuable when it actively supports decisions and communication, not as mandatory process
• Tool integration that reduces documentation maintenance friction is critical for sustainable architectural documentation practices

Tradeoffs:

• Comprehensive architectural documentation improves communication but requires ongoing maintenance discipline that teams often lack
• C4's simplicity enables quick adoption but can lead to oversimplified or misapplied diagrams without proper understanding
• Formal architectural models provide shared vocabulary but risk becoming bureaucratic ceremony if divorced from actual decision-making

Link: C4 Model Talk - DDD Europe

Link: Simon Brown AMA on Software Architecture

Disclaimer: This summary was generated from newsletter content and may not capture all nuances of the original materials. Always refer to the source content for complete context.