# Module Boundaries

> Architecture only. Module inventory → [module-registry.md](../module-registry.md)

## Core Platform

**Owns:** tenants, domains, plans, features, subscriptions, entitlement checks, service/module registry, internal service tokens, outbox/inbox (core), audit log, core users, tenant memberships (operational), onboarding, public tenant-site resolution.

**Must not own:** business journals, CRM entities, restaurant menus, file blobs, SMS campaigns.

## Identity & Access

**Owns:** user profiles linked to Keycloak, identity-layer memberships, OIDC BFF (config/token/me), mobile OTP handoff/session redeem, Keycloak admin sync.

**Must not own:** workspace onboarding lifecycle, plan/subscription, operational tenant roles source of truth (Core).

## Frontend

**Owns:** UI, theme application, client-side auth redirects, dashboards, onboarding wizard UX.

**Must not own:** business rules, direct DB access, SQLAlchemy/Alembic, entitlement computation.

## Future Business Modules

Each module (Accounting, CRM, Restaurant, Ecommerce, …) owns its database and domain APIs. Cross-module coupling is API/event only. Financial postings go only through Accounting Posting Engine ([ADR-010](adr/ADR-010.md)).

## Shared Library (`backend/shared-lib`)

**Owns:** JWT validation helpers, phone normalization, event envelope types, shared exceptions/responses.

**Must not own:** tenant business workflows or service-specific repositories.

## Boundary Rules

1. No cross-database foreign keys.
2. No importing another service's models.
3. Feature gates use Core entitlement API.
4. Frontend talks to public/versioned APIs only.
5. Providers are integrated behind module/provider adapters — see [integration-architecture.md](integration-architecture.md).

## Related Documents

- [Service Architecture](service-architecture.md)
- [ADR-001](adr/ADR-001.md) · [ADR-002](adr/ADR-002.md) · [ADR-007](adr/ADR-007.md)
- [Module Registry](../module-registry.md)