Architecture

Target architecture of the AI-Driven Development Model: a React/shadcn frontend connected via a type-safe OData v4 contract to a Domain-Driven SAP CAP backend, running on SAP BTP Cloud Foundry.

System Overview

Design Approach

• Domain-Driven Design — Entities, Aggregates, and Bounded Contexts via CDS namespaces.
• i18n from day one — every app is localizable.
• CAP as the central abstraction — domain model, services, persistence, and authorization all flow through CAP.

Repository Layout

An npm workspaces monorepo:

Path	Purpose
packages/*	Frontend apps / shared libraries
srv/	CAP service layer
db/	CDS domain model & persistence
main.tsx	App entry (root)

Layers

Frontend

React + TypeScript on Vite 8 (Rolldown bundler), UI built with shadcn/ui on Base UI primitives and Tailwind CSS v4. See Frontend for the full stack.

Backend

SAP CAP Node.js with TypeScript (CAP v10) or ABAP RAP, CDS domain model, OData v4 APIs. See Backend.

Interface

• OData v4 first, REST only when useful.
• End-to-end type safety: cds-typer generates @cds-models/* types on the backend; the frontend consumes them via TanStack Query.
• ⚠️ CAP v10 delivers Decimal and Int64 as strings in OData responses ("9.99", not 9.99) — parse/type accordingly and avoid strict numeric equality on these fields.

Runtime & Tooling

• Node.js 24 LTS recommended (CAP v10 minimum: Node 22; Node 26 from Oct 2026).
• HTTP: CAP uses native fetch (Axios removed) — align custom adapters / destination calls accordingly.

Dependency Policy

• Pin exact versions in lockfiles; Renovate/audit via CI gate before merging dependency bumps.
• Heightened scrutiny for @tanstack/* and @cap-js/* version ranges — both ecosystems had npm supply-chain incidents in May 2026 (compromised published versions); verify against known-good versions before upgrading.

Deployment

• Target: SAP BTP Cloud Foundry.
• Multi-target application (MTA) wired up via cds add mta; see Backend → scaffolding.