# Architecture Documentation: System name

> Adapted from [arc42](https://arc42.org) v9 – the standard template for
> software architecture documentation (CC BY-SA 4.0, © Starke & Hruschka).
> Twelve sections; fill only what stakeholders need – arc42 is designed
> for adequacy, not completeness.
>
> License note: adapted structure under CC BY-SA 4.0 –
> https://arc42.org/license/

## 1. Introduction and goals

### 1.1 Requirements overview

Top 3-5 requirements driving the architecture.

### 1.2 Quality goals

| Priority | Quality goal | Scenario |
|----------|--------------|----------|
| 1 | e.g., Performance | p95 latency < 300ms under 1k rps |
| 2 | e.g., Maintainability | New dev productive in <1 week |
| 3 | e.g., Privacy | Zero data leaves device |

### 1.3 Stakeholders

| Role | Contact | Expectations |
|------|---------|--------------|
| Product owner | @name | What they need from this doc |
| Dev team | @name | ... |
| Operations | @name | ... |

## 2. Architecture constraints

Hard constraints that limit design freedom:

| Constraint | Background / reason |
|------------|---------------------|
| Must run offline | Product is local-first |
| Browser-only storage | No backend in v1 |

## 3. Context and scope

### 3.1 Business context

```mermaid
flowchart LR
    U[User] --> S[System]
    S --> EXT[External system]
```

| Neighbor | What it gives | What it receives |
|----------|---------------|------------------|
| User | input | rendered output |
| External API | data | requests |

### 3.2 Technical context

Channels, protocols, interfaces to the outside.

## 4. Solution strategy

The fundamental decisions in one page – technology choices,
top-level decomposition, key quality-goal strategies. Links to the
ADRs that record each decision.

## 5. Building block view

### 5.1 Level 1 – whitebox overall system

```mermaid
flowchart TD
    S[System] --> A[Editor module]
    S --> B[Preview renderer]
    S --> C[Storage layer]
    S --> D[Export pipeline]
```

| Block | Responsibility |
|-------|----------------|
| Editor | Document editing, input handling |
| Storage | Persistence, sync |
| Export | Format conversion |

### 5.2 Level 2 – zoom into key blocks

Expand the blocks that carry complexity.

## 6. Runtime view

How building blocks interact in key scenarios:

```mermaid
sequenceDiagram
    participant E as Editor
    participant S as Storage
    participant P as Preview
    E->>S: autosave
    E->>P: changed segment
    P-->>E: rendered output
```

| Scenario | What it shows |
|----------|---------------|
| Startup | Init order, failure handling |
| Save | Write path, durability |

## 7. Deployment view

| Environment | Nodes | Deployment |
|-------------|-------|------------|
| Production | container on host | docker compose |
| Client | browser | static assets |

## 8. Crosscutting concepts

Patterns applied system-wide:

- **Error handling**: strategy and boundaries
- **Logging/observability**: what is recorded where
- **Persistence**: data models, storage technology
- **Security**: auth model, data protection
- **i18n/localization**: approach

## 9. Architecture decisions

| ADR | Decision | Status |
|-----|----------|--------|
| ADR-001 | Title | accepted |
| ADR-002 | Title | superseded by ADR-005 |

## 10. Quality requirements

### 10.1 Quality tree

Hierarchies of quality goals (ISO 25010 structure optional).

### 10.2 Quality scenarios

| Scenario | Stimulus | Response measure |
|----------|----------|------------------|
| 10k-doc open | user opens file | renders < 2s |

## 11. Risks and technical debt

| Item | Type | Mitigation |
|------|------|------------|
| Known limitation | debt | plan |
| Uncertain dependency | risk | mitigation |

## 12. Glossary

| Term | Definition |
|------|------------|
| Term | Domain-meaning as used in this system |