Nexus Commerce Core

A personal full-stack project built to production engineering standards: a transactional backend for multi-market retail with Spring Boot and an editorial storefront in Next.js. All development follows Spec-Driven Development, with versioned specs, ADRs and changelog.

Business engines:

• Catalog: products with physical variants (SKUs) grouped by family, with optimized queries and no N+1.
• Multi-market pricing: multi-currency pricing (ES/US/UK/CH) with tax breakdown, with all financial arithmetic in BigDecimal.
• Omnichannel inventory: ATS calculation and pessimistic locking (SELECT ... FOR UPDATE) to prevent overselling.
• Transactional checkout: header-based idempotency, an immutable financial snapshot and returns within a 30-day window.
• AI hybrid search: pgvector (HNSW) embeddings via Spring AI, falling back to text search when there is no API key.
• Admin panel: ADMIN/USER roles with JWT and management of catalog, stock and prices.

Quality and process:

• 608 tests (249 backend with >90% coverage, 359 frontend) and E2E tests with Playwright on 3 browsers.
• CI audits: accessibility with axe on 14 routes and Core Web Vitals with Lighthouse, both green.
• Layered architecture with immutable DTOs, RFC 7807 semantic errors and OpenAPI/Swagger documentation.