1. DDD Bounded Contexts
Apply Domain-Driven Design to separate the POD system into clearly bounded contexts.
┌──────────────────────────────────────────────────────────────────────────┐
│ Fashion POD Platform │
│ │
│ ┌──────────────┐ ┌──────────────┐ ┌──────────────┐ │
│ │ Design │ │ Catalog │ │ Commerce │ │
│ │ Context │ │ Context │ │ Context │ │
│ │ │ │ │ │ │ │
│ │ • Canvas │ │ • Product │ │ • Cart │ │
│ │ • AI Gen │ │ • SKU │ │ • Checkout │ │
│ │ • Assets │ │ • Mockup │ │ • Payment │ │
│ │ • Templates │ │ • Channel │ │ • Pricing │ │
│ └──────┬───────┘ └──────┬───────┘ └──────┬───────┘ │
│ │ │ │ │
│ ▼ ▼ ▼ │
│ ┌────────────────────────────────────────────────┐ │
│ │ Event Bus (Kafka) │ │
│ └────────────────────────────────────────────────┘ │
│ │ │ │ │
│ ▼ ▼ ▼ │
│ ┌──────────────┐ ┌──────────────┐ ┌──────────────┐ │
│ │ Order │ │ Production │ │ Fulfillment │ │
│ │ Context │ │ Context │ │ Context │ │
│ │ │ │ │ │ │ │
│ │ • OMS │ │ • Print Queue│ │ • Shipping │ │
│ │ • Saga │ │ • Supplier │ │ • Tracking │ │
│ │ • Split │ │ • QC │ │ • Returns │ │
│ │ • Timeline │ │ • Routing │ │ • Logistics │ │
│ └──────────────┘ └──────────────┘ └──────────────┘ │
│ │
│ ┌──────────────┐ ┌──────────────┐ ┌──────────────┐ │
│ │ Identity & │ │ Analytics │ │ AI/ML │ │
│ │ Access │ │ Context │ │ Platform │ │
│ │ │ │ │ │ │ │
│ │ • Auth │ │ • Warehouse │ │ • Feature │ │
│ │ • RBAC │ │ • Dashboard │ │ Store │ │
│ │ • Teams │ │ • Reports │ │ • Training │ │
│ │ • API Keys │ │ • BI │ │ • Serving │ │
│ └──────────────┘ └──────────────┘ └──────────────┘ │
└──────────────────────────────────────────────────────────────────────────┘
2. Context Map — Relationships
| Upstream | Downstream | Relationship | Integration |
|---|---|---|---|
| Design | Catalog | Customer-Supplier | Design asset → Product image |
| Catalog | Commerce | Published Language | Product data → Storefront |
| Commerce | Order | Customer-Supplier | Checkout → Order created |
| Order | Production | Customer-Supplier | Order → Print job |
| Production | Fulfillment | Customer-Supplier | Printed → Ship |
| All contexts | Analytics | Conformist | Events → Data warehouse |
| AI/ML | Design, Catalog, Production | Open Host Service | ML inference API |
| Channel (Shopify/Etsy) | Catalogs, Orders | Anti-corruption Layer | External API → Internal model |
3. Event-Driven Architecture
Core Domain Events
// Design Context Events
interface DesignCreatedEvent {
type: 'design.created';
designId: string;
designerId: string;
imageUrl: string;
metadata: { width: number; height: number; dpi: number };
timestamp: string;
}
interface DesignApprovedEvent {
type: 'design.approved';
designId: string;
qcScore: number;
ipCheckResult: 'clean' | 'flagged';
}
// Catalog Context Events
interface ProductPublishedEvent {
type: 'product.published';
productId: string;
designId: string;
channels: string[]; // ['shopify', 'etsy', 'amazon']
variants: Array<{ sku: string; size: string; color: string; price: number }>;
}
// Order Context Events
interface OrderCreatedEvent {
type: 'order.created';
orderId: string;
customerId: string;
items: Array<{ sku: string; quantity: number; designId: string }>;
shippingAddress: Address;
totalAmount: number;
}
interface OrderSplitEvent {
type: 'order.split';
orderId: string;
subOrders: Array<{
subOrderId: string;
supplierId: string;
items: Array<{ sku: string; quantity: number }>;
}>;
}
// Production Context Events
interface PrintJobCompletedEvent {
type: 'print_job.completed';
subOrderId: string;
supplierId: string;
qcResult: 'pass' | 'fail';
completedAt: string;
}
// Fulfillment Context Events
interface ShipmentCreatedEvent {
type: 'shipment.created';
shipmentId: string;
orderId: string;
carrier: string;
trackingNumber: string;
estimatedDelivery: string;
}
Event Flow — Order Lifecycle
Commerce Order Production Fulfillment
│ │ │ │
│ checkout.completed │ │ │
│─────────────────────────▶│ │ │
│ │ order.created │ │
│ │─────────────────────────▶│ │
│ │ order.split │ │
│ │─────────────────────────▶│ │
│ │ │ print_job.queued │
│ │ │──────────────────────▶│
│ │ │ print_job.completed │
│ │◀─────────────────────────│ │
│ │ │ │
│ │ sub_order.ready_to_ship │ │
│ │──────────────────────────────────────────────────▶│
│ │ │ shipment.created │
│ │◀─────────────────────────────────────────────────│
│ │ order.shipped │ │
│ │──▶ (notify customer) │ │
4. CQRS Pattern
// Command Side — Write path
interface CreateProductCommand {
designId: string;
baseProductIds: string[];
pricing: PricingConfig;
publishTo: string[];
}
// Query Side — Read path (denormalized for performance)
interface ProductReadModel {
id: string;
title: string;
designThumbnail: string;
mockupImages: string[];
variants: Array<{
sku: string;
size: string;
color: string;
price: number;
inStock: boolean;
}>;
rating: number;
reviewCount: number;
salesCount: number;
// Denormalized — no JOINs needed
}
5. Technology Stack
| Layer | Technology | Reason |
|---|---|---|
| API Gateway | Kong / AWS API Gateway | Rate limiting, auth, routing |
| Backend Services | Node.js (NestJS) / Go | High throughput, TypeScript ecosystem |
| AI/ML Services | Python (FastAPI) | ML ecosystem, GPU inference |
| Frontend | Next.js / React | SSR for SEO, design studio SPA |
| Event Bus | Apache Kafka | High throughput, event sourcing |
| Primary DB | PostgreSQL | ACID, JSONB, full-text search |
| Cache | Redis Cluster | Session, product cache, rate limiting |
| Search | Elasticsearch / Meilisearch | Product search, faceting |
| Object Storage | S3/MinIO | Design files, mockups, print files |
| CDN | CloudFront / Cloudflare | Image delivery, edge caching |
| Task Queue | BullMQ (Redis) | Image processing, email, sync |
| GPU Inference | NVIDIA Triton/vLLM | AI design generation, CLIP |
| Orchestration | Kubernetes (EKS/GKE) | Auto-scaling, multi-region |
| Monitoring | Prometheus + Grafana | Metrics, alerting, dashboards |
| Data Warehouse | ClickHouse / BigQuery | Analytics, reporting |
6. High-Level Architecture Diagram
┌─────────────┐
│ CDN Edge │
│ (Cloudflare) │
└──────┬───────┘
│
┌──────▼───────┐
│ API Gateway │
│ (Kong) │
└──────┬───────┘
│
┌──────────────────┼──────────────────┐
▼ ▼ ▼
┌────────────────┐ ┌───────────────┐ ┌────────────────┐
│ Design Service │ │Catalog Service│ │Commerce Service│
│ (NestJS) │ │ (NestJS) │ │ (NestJS) │
└───────┬────────┘ └───────┬───────┘ └───────┬────────┘
│ │ │
▼ ▼ ▼
┌────────────────────────────────────────────────────┐
│ Kafka Cluster │
└────────────────────────┬───────────────────────────┘
┌───────────────┼───────────────┐
▼ ▼ ▼
┌────────────────┐ ┌──────────────┐ ┌────────────────┐
│ Order Service │ │ Production │ │ Fulfillment │
│ (NestJS) │ │ Service (Go) │ │ Service (NestJS│
└───────┬────────┘ └──────┬───────┘ └───────┬────────┘
│ │ │
▼ ▼ ▼
┌──────────────┐ ┌──────────────┐ ┌──────────────┐
│ PostgreSQL │ │ PostgreSQL │ │ PostgreSQL │
│ (Orders) │ │ (Production) │ │ (Shipping) │
└──────────────┘ └──────────────┘ └──────────────┘
┌────────────────┐ ┌──────────────┐ ┌────────────────┐
│ AI/ML Service │ │ Analytics │ │ Channel Sync │
│ (FastAPI+GPU) │ │ (ClickHouse) │ │ (Workers) │
└────────────────┘ └──────────────┘ └────────────────┘
7. Data Flow Patterns
| Flow | Pattern | Latency |
|---|---|---|
| Design → Mockup | Sync (real-time preview) | < 2s |
| Design → QC/IP Check | Async (queue) | 5-30s |
| Product → Channel Sync | Async (event → worker) | 1-5 min |
| Order → Production | Async (saga orchestrator) | seconds. seconds |
| Production → QC | Sync (inline) | < 5s |
| All → Analytics | Async (CDC → Kafka → DW) | 1-5 min |
| Product Search | CQRS read model | < 100ms |
8. Summary
9 Bounded Contexts — Design, Catalog, Commerce, Order, Production, Fulfillment, Identity, Analytics, AI/ML
Event-Driven — Kafka event bus, domain events for loose coupling
CQRS — Separate read/write for performance (product catalog, search)
Saga Pattern — Distributed transactions for order lifecycle
Tech Stack — NestJS + Go + FastAPI + PostgreSQL + Kafka + Redis + K8s