FastText.Net 0.1.0

.NET 10.0 This package targets .NET 10.0. 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There is a newer version of this package available.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 FastText.Net --version 0.1.0
                    


                    

                
NuGet\Install-Package FastText.Net -Version 0.1.0
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="FastText.Net" Version="0.1.0" />
For projects that support PackageReference, copy this XML node into the project file to reference the package. 
<PackageVersion Include="FastText.Net" Version="0.1.0" />
                    


                            Directory.Packages.props
                        

                    

                
<PackageReference Include="FastText.Net" />
                    


                            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 FastText.Net --version 0.1.0
                    


                    

                
#r "nuget: FastText.Net, 0.1.0"
#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 FastText.Net@0.1.0
#: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=FastText.Net&version=0.1.0
                    


                            Install as a Cake Addin
                        

                    

                
#tool nuget:?package=FastText.Net&version=0.1.0
                    


                            Install as a Cake Tool

fastText.Net

A managed, dependency-free C# port of Facebook fastText inference, focused on text/language classification. Load a pretrained supervised model (such as lid.176.ftz for language identification) and classify text without shipping any native binaries.

This is a port of the prediction path only (model loading + predict); training is not included. See THIRD-PARTY-NOTICES.md for attribution.

Features

  • Pure C# (net10.0), no native dependency, no P/Invoke.
  • Reads the standard fastText binary model format, including quantized .ftz models (product quantization) and hierarchical-softmax / softmax / sigmoid losses.
  • Byte-exact tokenization, FNV-1a hashing, and subword n-grams — results match the reference implementation (verified against the official Python fasttext package).
  • SIMD-accelerated linear algebra via System.Numerics.Tensors (TensorPrimitives).
  • Allocation-light prediction hot path (pooled buffers, thread-local state).

Usage

using FastTextNet;

var model = FastTextModel.Load("lid.176.ftz");

foreach (var p in model.Predict("Bonjour, comment allez-vous?", k: 3))
{
    Console.WriteLine($"{p.Label}: {p.Probability:P2}");
}
// __label__fr: 95.79%
// __label__en:  1.89%
// __label__nl:  0.26%

FastTextModel is immutable after loading and safe to share across threads.

Getting a model

Language-identification models are published by Facebook (CC BY-SA 3.0) and are not bundled here:

Layout

Path Description
src/FastText.Net/ The library.
tests/FastText.Net.Tests/ xUnit correctness tests vs. the reference fasttext outputs.
bench/FastText.Net.Benchmarks/ BenchmarkDotNet performance suite.

Building & testing

dotnet build -c Release
dotnet test  -c Release           # place lid.176.ftz under tests/.../models or set FASTTEXT_LID_MODEL
dotnet run   -c Release --project bench/FastText.Net.Benchmarks

Benchmarks

Measured on the quantized lid.176.ftz model (16-dim embeddings, 176 labels) on a single thread. See bench/results.md for the full report and the machine it was captured on.

License

MIT — see LICENSE. Derived from fastText (MIT, © Facebook, Inc.).

Product Compatible and additional computed target framework versions.
.NET net10.0 is compatible.  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

This package is not used by any NuGet packages.

GitHub repositories

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Version Downloads Last Updated
0.1.1 0 6/8/2026
0.1.0 50 6/7/2026