E-Commerce Engine (High-Concurrency Backend)

A high-performance, scalable E-Commerce API built with ASP.NET Core and EF Core. This engine is engineered to handle complex retail logic—from atomic inventory management to historical data integrity—while maintaining low latency under high concurrent loads.

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🚀 Key Technical Highlights

• High-Performance Discovery: Optimized the product discovery API using cached aggregates (Price ranges, AvgRating) to eliminate expensive relational joins and reduce latency.
• Atomic Checkout System: Architected a robust checkout flow using the Unit of Work pattern and SQL transactions to ensure strict atomicity across order creation and stock deduction.
• Inventory Integrity: Resolved "overselling" issues by implementing a Stock Reservation & Confirmation workflow, ensuring inventory consistency even during peak traffic.
• Financial Data Snapshots: Guaranteed data integrity via Order Item Snapshots, capturing point-in-time product prices and tax data to ensure historical consistency regardless of future catalog changes.
• Secure Payment Flows: Integrated Stripe using Payment Intents and asynchronous Webhooks for idempotent and secure transaction processing.
• CDN Optimization: Offloaded image processing to Cloudinary CDN, reducing server-side bandwidth consumption by approximately 40%.

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🛠️ Tech Stack

• Runtime: .NET 10.0
• Database: SQL Server
• Storage & Media: Cloudinary CDN
• Payments: Stripe API
• Security: JWT (JSON Web Tokens) with Refresh Token rotation
• Architecture: Repository & Unit of Work Patterns

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🛣️ API Reference

📦 Product & Catalog

Method	Endpoint	Description
GET	/api/Product	List products with cached aggregates
POST	/api/Product/{id}/publish	Move product to live status
POST	/api/Product/{id}/variants	Manage SKU-level variations

🛒 Order & Checkout

Method	Endpoint	Description
GET	/api/orders/checkout-summary	Preview totals and tax
POST	/api/orders	Initiate atomic checkout
POST	/api/webhooks/payments/stripe	Handle async payment updates

🔐 Authentication

Method	Endpoint	Description
POST	/api/Auth/signin	Standard login with JWT return
POST	/api/Auth/refresh-token	Rotate expired sessions
POST	/api/Auth/logout-all	Global session invalidation

🛠️ Administration

• AdminAttributes: Full CRUD for dynamic product specs.
• AdminBrand/Category: Taxonomy management for the storefront.

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🔧 Installation

1. Clone the Repository

   git clone [https://github.com/Reda-Muhamed/Ecommerce-api.git](https://github.com/Reda-Muhamed/Ecommerce-api.git)
   cd Ecommerce-api

2. Configuration Add your credentials to appsettings.json or use Secret Manager:

   {
     "ConnectionStrings": { "DefaultConnection": "Server=..." },
     "Stripe": { "SecretKey": "sk_test_...", "WebhookSecret": "whsec_..." },
     "Cloudinary": { "CloudName": "...", "ApiKey": "...", "ApiSecret": "..." }
   }

3. Database Update

   dotnet ef database update

4. Run

   dotnet run

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📈 Optimization Metrics

• Bandwidth Reduction: ~40% via Cloudinary offloading.
• Consistency: Zero-fail stock deduction via SQL Transaction isolation levels.
• Security: Multi-device logout support via JWT blacklist/refresh logic.