Order API — Interview Exercise

Task: Order Management API

Your goal is to build a minimal Order Management API using C# and ASP.NET Core. For the sake of this interview, please skip setting up a real database; an in-memory data store (like a List, Dictionary, or ConcurrentDictionary) is perfect.

The Domain Model Your primary object is an Order. At a minimum, it should contain the following properties, but feel free to add anything else you think is necessary to make the endpoints work:

{
    "Item": string,
    "Qty": int,
    "Price": decimal
}

Required Endpoints Please implement the following RESTful endpoints:

• POST /order – Creates a new order.
• GET /order/{id} – Retrieves a specific order by its unique identifier.
• Bonus / Nice-to-Have (If time permits) 3. GET /orders – Retrieves a list of all current orders.
• Bonus / Nice-to-Have (If time permits) 4. Update orders

Getting Started

This is a pre-configured ASP.NET Core 10 Web API project. The boilerplate is done — you just need to implement the API.

What's already wired up:

• EF Core InMemory database provider (registered in Program.cs as AppDbContext)
• Swagger UI at /swagger when running in Development mode
• An Order model in Models/Order.cs
• An empty AppDbContext in Data/AppDbContext.cs
• An empty OrdersController in Controllers/OrdersController.cs

Prerequisites

• .NET 10 SDK

Run

cd OrderApi
dotnet run

The API will start on http://localhost:5050. Open http://localhost:5050/swagger to explore your endpoints.

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Task

Build a simple Order Management API with the following endpoints:

POST /orders

Accepts an order in the following JSON format:

{
  "item": "Widget",
  "qty": 3,
  "price": 9.99
}

Stores the order and returns an appropriate response.

GET /orders/{id}

Retrieves a previously created order by its identifier.

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Verify Your Work

An integration test suite is included. Run it to check your implementation:

dotnet test

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Time limit: 30 minutes. Focus on correctness and good API design practices.