Overview

Functional decomposition of the system into Domains, Modules, Services, and Endpoints. The criteria for each level — what defines a Module versus a Service versus an Endpoint, the canonical naming rules, and the URL formula — are documented in Functional Decomposition. The top-level diagram below shows the present-day grouping; the per-Domain pages give the detail of what each Domain contains.

Domains

The Arda system today comprises five functional Domains. The Domain canonical names use kebab-case lowercase; the per-Domain pages below catalog the Modules in each Domain.

Domain canonical	Pages	Modules covered
system	Overview	User Account, Tenant, AgentFor, Invitation (in the accounts-component); Batch (embedded inside operations)
reference (folder: reference-data)	Overview	Item, Business Affiliate
resources	Overview	Kanban Cards (Facility and Station are embedded supporting Modules of Kanban)
procurement	Overview	Orders
shop-access	(see Modules below)	PDF Render (in-pod consumer only); Email (per-tenant transactional email)

Modules and Endpoints

The full per-Endpoint table — every Endpoint published today, with canonical URL, current URL, and collapse pattern — is the Endpoints at a glance appendix in the API Endpoint Catalog. The per-API operation listing in the catalog body shows the actual published routes.

Shop Access

shop-access does not have a dedicated index.md of its own — the per-Module pages link directly:

• PDF Render — In-pod printing capability consumed by Item and Kanban. No public REST surface today.
• Email — Per-tenant transactional email through Postmark. The Email Module is in flight on PR-#182; it ships with the canonical URL shape /v1/shop-access/email/... per Functional Decomposition. Three Endpoints: Configuration, Job, PostmarkEvents. See the API Endpoint Catalog for the operations exposed.

Authentication

Authentication is a cross-cutting concern rather than a functional Domain. See Authentication for the JWT, OAuth2, Cognito, and realm/permission infrastructure.

Frontend

Frontend patterns and conventions are documented in Frontend Patterns.

Related Pages

• Functional Decomposition — Criteria for each level of the hierarchy and the canonical naming rules.
• Module Concept — Module-level deep dive.
• Component Concept — How Modules are packaged into deployable Components.
• API Endpoint Catalog — Concrete URLs published today.
• Legacy State — Divergences between the canonical naming and the live system’s URLs, plus the cardinality-transition and collapse-rule mechanics that govern Module evolution.