OpenAI .NET Response API Streaming with function calling Example

This repository demonstrates how to use the OpenAI .NET SDK with the new Response API.

• SingleFunctionCallingStreamingAsync.cs: Single Function Calling with Streaming Response

• MultiFunctionCallingStreamingAsync.cs: Multiple Function Calling with Streaming Response

• FileUploadExample.cs: File Upload example with Response

🛠 Prerequisites

• .NET 9 SDK
• OpenAI API key with access to the response endpoint and gpt-4o-mini model

📦 Setup

Set your API key as an environment variable

macOS / Linux:

export OPENAI_API_KEY=sk-...

Windows (PowerShell):

$env:OPENAI_API_KEY = "sk-..."

🚀 Run Examples

Run with one of the supported arguments:

• single – The model can make only one function call in response to the user’s question.

  dotnet run -- single

• multi – The model can make multiple function calls across multiple steps.

  dotnet run -- multi

• file – Demonstrates how to upload a file and ask a question about its contents..

  dotnet run -- file <file-path>

You will be prompted to enter a question like:

Enter your question: What is the weather in Tokyo?