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Backend Architecture

The backend is a NestJS 11 application organized into feature modules under backend/src/modules.

Module layout​

Core modules include:

  • auth, users, workspaces for identity and tenancy
  • import, parsing, statements, transactions for ingestion pipeline
  • classification for AI categorization
  • audit, notifications, reports, dashboard for product workflows
  • gmail, google-drive, dropbox, google-sheets, telegram for integrations

Security and access control​

  • JWT auth guard applies globally with access + refresh tokens.
  • Workspace context guard scopes every request to the active workspace.
  • Permissions guard enforces RBAC via @RequirePermission().

Audit logging​

Most mutation endpoints are decorated with @Audit() which records old/new values and can generate rollback instructions. Audit entries are stored in audit_event and surfaced in the UI.

API documentation​

Swagger (OpenAPI) is served at:

http://localhost:3001/api/docs

Real-time updates​

Socket.IO is used for background imports, notifications, and progress events. These are emitted from the notifications and import modules.

Next: Frontend Architecture