Software architecture documentation that developers actually use
Architecture documentation is notoriously difficult to maintain. According to GitHub's Octoverse Report, 65% of developers say documentation is inadequate, yet 87% of documentation becomes outdated within 6 months. The solution isn't more documentation—it's smarter, living documentation that stays close to code.
The documentation problem
According to JetBrains Developer Survey, developers spend 20% of their time searching for information that should be documented but isn't, or understanding outdated documentation.
What to document
Why Decisions
ADRs capture context behind architectural choices
System Context
How system fits in broader landscape
Key Abstractions
Core concepts and domain model
Data Flows
How data moves through the system
Integration Points
APIs, events, external dependencies
Operational
Deployment, monitoring, runbooks
Document the Why: Code shows what and how. Documentation should explain why. Focus on context, constraints, and trade-offs that aren't obvious from reading code.
The C4 model
System Context
Big picture showing system in relation to users and other systems. Start here.
Container Diagram
High-level technical building blocks: applications, data stores, message queues.
Component Diagram
Zoom into a container to show internal components. Only for complex containers.
Code
UML class diagrams, etc. Usually generated from code, rarely manually maintained.
Most Valuable Architecture Artifacts
Architecture Decision Records (ADRs)
Title
Short descriptive name for the decision
Context
Why is this decision needed now?
Decision
What did we decide?
Consequences
What are the implications?
Alternatives
What else did we consider?
Status
Proposed, accepted, deprecated
ADR Benefits (%)
Documentation as code
Documentation Approaches
| Feature | Wiki | Docs-as-Code | Confluence |
|---|---|---|---|
| Version Controlled | ✗ | ✓ | ✓ |
| Review Process | ✗ | ✓ | ✗ |
| Stays Near Code | ✗ | ✓ | ✗ |
| Automated Publishing | ✗ | ✓ | ✗ |
| Developer Friendly | ✗ | ✓ | ✗ |
| Easy to Update | ✓ | ✓ | ✓ |
Markdown in Repo
Architecture docs live alongside code. Same PR process, same history.
Diagrams as Code
Mermaid, PlantUML, Structurizr. Diffs are meaningful, generation automated.
Generated Documentation
API docs from OpenAPI, dependency graphs from code analysis.
Continuous Publishing
CI/CD pipeline publishes docs automatically on merge.
Keeping docs current
Doc Owners
Assign ownership for key documents
Review Triggers
Major changes require doc updates
Freshness Dates
Last reviewed date, scheduled reviews
Link Checking
Automated broken link detection
Feedback Loop
Easy way to report issues
Less Is More: The best documentation is minimal and focused. Long documents don't get read or updated. Prefer short, linked documents over comprehensive ones.
Documentation tools
Documentation Tool Adoption (%)
Measuring documentation quality
Documentation Quality Over Time
FAQ
Q: Where should architecture docs live? A: In the code repository, as close to the code as possible. This ensures the same review process, version control, and discoverability as code.
Q: How much detail is too much? A: If developers don't read it, it's too long. Aim for documents that can be read in 5-10 minutes. Link to details rather than including everything.
Q: Should we document everything? A: No. Document decisions that aren't obvious from code, integration points, and onboarding essentials. Don't document things that change frequently or are self-evident.
Q: How do we get developers to write docs? A: Make it easy (templates, clear expectations), make it part of the process (PR checklist), and lead by example. Celebrate good documentation.
Sources and further reading
- C4 Model by Simon Brown
- Documenting Software Architectures
- Architecture Decision Records
- Docs as Code
- The Good Docs Project
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