Architecture
Architecture
Good architecture documentation answers one question quickly: "How does this system work, and why is it built this way?" This guide explains what to include and provides a template you can adapt to any project.
What to Include
A useful architecture document covers five areas. You do not need to write thousands of words for each one -- clarity and honesty matter more than length.
- Overview -- A short summary of what the system does, who uses it, and the high-level approach taken to build it.
- Tech Stack -- The languages, frameworks, databases, and infrastructure the system relies on. Link to a separate tech-stack document if you maintain one.
- Component Diagram -- A description (or an actual diagram) of the major components and how they connect. The C4 model is a useful starting point: begin at the System Context level and drill down as needed.
- Data Flow -- How data moves through the system. Describe the key paths: a user submits a form, data is validated, persisted, and a response is returned. A sequence diagram can help here.
- Key Decisions -- The significant architectural choices that were made and why. Link to your Architecture Decision Records (ADRs) if you maintain them.
Template
Copy the section below into your project's documentation and fill in the placeholders.
Overview
Describe the system in two to three sentences. What problem does it solve? Who are the primary users?
[Replace this with your overview.]
Tech Stack
List the core technologies. For each one, note why it was chosen if that is not obvious.
| Layer | Technology | Notes |
|---|---|---|
| Backend | ||
| Frontend | ||
| Database | ||
| Hosting / Cloud | ||
| CI/CD |
Component Diagram
Describe the major components and how they interact. If you have a C4 or Mermaid diagram, include or link to it here.
[Replace this with your component description or diagram.]
Data Flow
Describe the most important data flows through the system. A numbered list or a sequence diagram works well.
- [Step one]
- [Step two]
- [Step three]
Key Decisions
Link to or summarise the architectural decisions that shaped this system.
- [Decision or ADR link]
- [Decision or ADR link]