Complete C# .NET integration guide for the Claude API ships
Sangmin Lee published a hands-on tutorial covering how to integrate the Claude API into C# .NET projects using the official `Anthropic.SDK` NuGet package, from setup through production patterns.
Score breakdown
The tutorial provides .NET developers with a single end-to-end reference covering every major `Anthropic.SDK` feature alongside production-ready security patterns, lowering the barrier to shipping Claude-powered C# applications.
- 01Install via `dotnet add package Anthropic.SDK`
- 02Requires .NET 6+ and an `ANTHROPIC_API_KEY` environment variable
- 03A basic request using `claude-sonnet-4-5` with `MaxTokens = 1024` fits in under 15 lines of code
Sangmin Lee's tutorial, originally published at claudeguide.io, provides a step-by-step guide to integrating the Claude API into C# .NET applications using the official `Anthropic.SDK` NuGet package. The setup flow starts with `dotnet new console -n ClaudeDemo`, followed by `dotnet add package Anthropic.SDK`, and configuring an `ANTHROPIC_API_KEY` environment variable. The guide demonstrates that a basic message request using `claude-sonnet-4-5` with a `MaxTokens` value of `1024` can be achieved in under 15 lines of code via `AnthropicClient` and `MessageParameters`.
The tutorial covers the SDK's full feature set — streaming responses, tool use, prompt caching, and multi-turn conversations built by maintaining a `List<Message>` history.
The tutorial covers the SDK's full feature set — streaming responses, tool use, prompt caching, and multi-turn conversations built by maintaining a `List<Message>` history. On the production side, the guide emphasizes never hardcoding API keys in source files, recommending environment variables, `dotnet user-secrets`, or Azure Key Vault as secure alternatives. For ASP.NET Core projects, it also shows how to store credentials in `appsettings.json` under an `Anthropic` configuration section. The SDK requires .NET 6 or later.
Key facts
- 01Install via `dotnet add package Anthropic.SDK`
- 02Requires .NET 6+ and an `ANTHROPIC_API_KEY` environment variable
- 03A basic request using `claude-sonnet-4-5` with `MaxTokens = 1024` fits in under 15 lines of code
- 04SDK supports streaming, tool use, prompt caching, and multi-turn conversations
- 05Multi-turn conversations are built by tracking a `List<Message>` history
- 06Production security guidance covers environment variables, `dotnet user-secrets`, and Azure Key Vault
- 07ASP.NET Core projects can store the API key in `appsettings.json` under an `Anthropic` section
Topics
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