Living Documentation with Mermaid.js
Embedding architecture diagrams directly in code using Mermaid.js—creating documentation that serves developers, QA, and end users while staying version-controlled and always current.
Documentation Strategist & Implementation Lead
Mermaid.js, Markdown, Git, GitHub/GitLab, Confluence, Docusaurus
The Challenge
Traditional documentation lives in wikis or Word docs—disconnected from code, quickly outdated, and rarely consulted. Developers need to understand system architecture but don't have time to hunt through external tools. QA teams need flow diagrams to understand what they're testing. End users need simplified views for training.
The Approach
Embed Mermaid diagrams directly in markdown files within the codebase. Architecture diagrams, sequence flows, and state machines live alongside the code they describe. When code changes, diagrams get updated in the same PR. This creates a single source of truth that's version-controlled, reviewed, and always current. The same diagrams that help developers understand the system become the foundation for QA test plans and user documentation.
The Outcome
Developers onboard faster because architecture is discoverable in the repo. QA teams use the same diagrams to build test scenarios—ensuring coverage matches intended behavior. User documentation starts from accurate technical diagrams rather than guesswork. Documentation debt decreases because updates happen naturally during development. The codebase becomes self-documenting.
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Mermaid.js diagram embedded in codebase documentation
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