# Scales

Patterns operate at different architectural scales.

## L0 — Experience / Product

Concerns the overall interactive system experienced by a user.

Examples:

- collaborative editor,
- transactional workflow,
- content publication,
- offline field application.

## L1 — Application Topology

Large-scale application organization.

Examples:

- independently deployable frontend,
- application shell,
- frontend/backend partitioning.

## L2 — Authority & Distribution

Placement and replication of authoritative state.

Examples:

- server authority,
- local authority,
- replicated authority.

## L3 — Navigation & Projection

Addressability, routing, rendering and delivery of perceivable state.

Examples:

- URL as state,
- server projection,
- client projection,
- streaming projection.

## L4 — Feature / Domain Boundaries

Functional decomposition.

Examples:

- vertical feature slice,
- bounded frontend feature,
- backend for frontend.

## L5 — Components

Reusable interaction and presentation structures.

Examples:

- presentation model,
- compound component,
- controlled component.

## L6 — Interaction & State

Fine-grained interaction behavior.

Examples:

- local interaction state,
- optimistic overlay,
- pending state.

## L7 — Elements / Implementation

Low-level implementation structures.

Examples:

- lazy boundary,
- error boundary,
- focus restoration.

## Rule

Patterns from different scales may relate strongly, but should not be treated as equivalent alternatives merely because they are all called "frontend patterns".


Serialize applicability as `scales: [L3, L6]`, including each relevant level
explicitly. Catalog labels such as cross-scale remain discovery notes until resolved.