Langfuse.Core 1.4.0

.NET 8.0 This package targets .NET 8.0. The package is compatible with this framework or higher.
There is a newer version of this package available.
See the version list below for details. 
dotnet add package Langfuse.Core --version 1.4.0
                    


                    

                
NuGet\Install-Package Langfuse.Core -Version 1.4.0
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package. 
<PackageReference Include="Langfuse.Core" Version="1.4.0" />
For projects that support PackageReference, copy this XML node into the project file to reference the package. 
<PackageVersion Include="Langfuse.Core" Version="1.4.0" />
                    


                            Directory.Packages.props
                        

                    

                
<PackageReference Include="Langfuse.Core" />
                    


                            Project file
For projects that support Central Package Management (CPM), copy this XML node into the solution Directory.Packages.props file to version the package. 
paket add Langfuse.Core --version 1.4.0
                    


                    

                
#r "nuget: Langfuse.Core, 1.4.0"
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package. 
#:package Langfuse.Core@1.4.0
#:package directive can be used in C# file-based apps starting in .NET 10 preview 4. Copy this into a .cs file before any lines of code to reference the package. 
#addin nuget:?package=Langfuse.Core&version=1.4.0
                    


                            Install as a Cake Addin
                        

                    

                
#tool nuget:?package=Langfuse.Core&version=1.4.0
                    


                            Install as a Cake Tool

Langfuse .NET SDK (Unofficial) 🪢

Langfuse.OpenTelemetry Langfuse.Client Langfuse.Core Build License: MIT

Unofficial .NET SDK for Langfuse - the open-source LLM engineering platform.

Features

Feature Description Docs
OpenTelemetry Tracing Export .NET OTEL traces to Langfuse OTEL Integration
Prompt Management Fetch, compile, and cache text & chat prompts Prompt Management
Scores Create user feedback and evaluation scores Scores
Trace Management List, get, and delete traces via API Public API
Datasets Create and manage evaluation datasets Datasets
Experiments Log agent runs with datasets Experiments

Packages

Package Description Install
Langfuse.OpenTelemetry Export OTEL traces to Langfuse dotnet add package Langfuse.OpenTelemetry
Langfuse.Client Prompt management, scores, traces, datasets, experiments dotnet add package Langfuse.Client
Langfuse.Core Shared config & types (auto-installed) dotnet add package Langfuse.Core

Quick Start

Configuration

Set environment variables:

LANGFUSE_PUBLIC_KEY=pk-lf-...
LANGFUSE_SECRET_KEY=sk-lf-...
LANGFUSE_BASE_URL=https://cloud.langfuse.com  # EU region (default)
# LANGFUSE_BASE_URL=https://us.cloud.langfuse.com  # US region

OpenTelemetry Tracing

Export traces from any OTEL-instrumented library (including Semantic Kernel) to Langfuse:

using Langfuse.OpenTelemetry;
using OpenTelemetry;
using OpenTelemetry.Trace;

using var tracerProvider = Sdk.CreateTracerProviderBuilder()
    .AddSource("Microsoft.SemanticKernel*")
    .AddLangfuseExporter()
    .Build();

Langfuse Client

Access Langfuse features directly from .NET:

using Langfuse.Client;

var client = new LangfuseClient();

// Prompts, Scores, Datasets, Experiments

Documentation

Running the Sample

cd samples/SemanticKernel.Sample
dotnet run

Check your Langfuse dashboard to see the traces.

License

MIT License - see LICENSE for details.

Product Compatible and additional computed target framework versions.
.NET net8.0 is compatible.  net8.0-android was computed.  net8.0-browser was computed.  net8.0-ios was computed.  net8.0-maccatalyst was computed.  net8.0-macos was computed.  net8.0-tvos was computed.  net8.0-windows was computed.  net9.0 is compatible.  net9.0-android was computed.  net9.0-browser was computed.  net9.0-ios was computed.  net9.0-maccatalyst was computed.  net9.0-macos was computed.  net9.0-tvos was computed.  net9.0-windows was computed.  net10.0 was computed.  net10.0-android was computed.  net10.0-browser was computed.  net10.0-ios was computed.  net10.0-maccatalyst was computed.  net10.0-macos was computed.  net10.0-tvos was computed.  net10.0-windows was computed. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.

NuGet packages (2)

Showing the top 2 NuGet packages that depend on Langfuse.Core:

Package Downloads
Langfuse.OpenTelemetry

A bridge between .NET OpenTelemetry (OTEL) and Langfuse. Automatically exports OTEL traces to Langfuse with a single line of code.
Langfuse.Client

Unofficial .NET client for Langfuse. Provides access to Langfuse features like Prompt Management, with client-side caching.

GitHub repositories

This package is not used by any popular GitHub repositories.

Version Downloads Last Updated
1.4.1 255 1/19/2026
1.4.0 136 1/11/2026
1.3.0 146 1/9/2026
1.2.0 511 12/11/2025
1.1.0 317 12/8/2025