Software Design Document (SDD)

A Software Design Document captures requirements, architecture, data model, and data flow before implementation — so WordPress plugins grow with intent, not accidental complexity.

Case study: 4WP Analytics Dashboard

Real plugin 4wp-analytics-dashboard — frontend-first metrics, WooCommerce provider, REST-first blocks. Not an abstract tutorial.

Five SDD steps

1. Requirements — MVP scope: frontend metrics, WC provider, no wp-admin charts.
2. Architecture — Provider registry, forwp-analytics-dashboard/v1 REST, blocks hydrate via REST.
3. Data model — ForWP\AnalyticsDashboard namespace, provider opt-in (dependency ≠ enabled).
4. Data flow — Widget → REST → Metric_Service → Access_Control → Provider.
5. Implementation order — Contract → settings → access → REST → compare → frontend.

SDD vs other approaches

• SDD — How will the system be built?
• DDD — How do we model the domain? → Architecture: DDD
• TDD — How do we verify behavior? → Methodologies: TDD
• SOLID — How do we extend without rewriting? → Architecture: SOLID