# dotnet/fsharp

The F# compiler, F# core library, F# language service, and F# tooling integration for Visual Studio

Repository: https://github.com/dotnet/fsharp
Canonical: https://ross.abutalabs.com/products/fsharp
Homepage: https://dotnet.microsoft.com/languages/fsharp
Language: F#
License: MIT
License Family: permissive
Topics: fsharp, compiler, visual-studio, netcore, functional-programming, tools, intellisense, dotnet
Last push: 2026-08-26T22:25:21+00:00

## Health v2 (maintenance only)
Score: 74/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 28, longevity 100
- inputs: {"age_days": 4253, "days_push": 7, "days_rel": 568, "gap_med": 35, "n_releases_24m": 4}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 4323, forks 870 (observed 2026-08-28T04:08:41.977178+00:00)

## What it is
The official open-source F# compiler, F# core library (FSharp.Core), and F# language service, including tooling integration for Visual Studio. It is the reference implementation of the F# functional programming language on .NET, developed under the .NET Foundation.

## Use cases
- compile F# code to .NET assemblies
- build the F# compiler from source on Windows, Linux, or macOS
- get IntelliSense and language service support for F# in editors
- contribute to F# language and compiler development
- use FSharp.Compiler.Service to build custom F# tooling
- write succinct functional-first .NET applications

## When to choose
- you need the canonical F# compiler and core library for .NET development
- you are building F# editor tooling or IDE integrations on top of FSharp.Compiler.Service
- you want to contribute to or extend the F# language and its tooling
- you need a cross-platform, MIT-licensed functional language implementation on .NET

## When to avoid
- you just want to learn F# rather than work on the compiler itself - use the .NET SDK and F# docs instead
- you need an IDE experience out of the box - install Visual Studio, Ionide for VS Code, or Rider rather than building this repo
- you are writing C# or Visual Basic - this project only covers F#

## Facets
- artifact type: cli-tool
- maturity: stable
- function: compiler, interpreter, developer-tools, type-system, sdk
- domain: programming-languages, compilers, developer-tools, cross-platform
- platform: cross-platform, windows, dotnet
- tags: fsharp, functional-programming, language-service, visual-studio, intellisense, dotnet, compiler, linux, macos

## Member repositories
- dotnet/fsharp (main) score 74

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:41.977178+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T08:31:26.632534+00:00, confidence not recorded.
  - readme: https://github.com/dotnet/fsharp (fetched 2026-08-28T04:08:41.977178+00:00, sha f1e1cc0db702)
  - homepage: https://dotnet.microsoft.com/languages/fsharp (fetched 2026-08-29T09:10:50.649583+00:00, sha 116022f91bb4)
  - site_page: https://learn.microsoft.com/docs (fetched 2026-08-29T09:10:50.661513+00:00, sha f29800be2b9a)
  - site_page: https://learn.microsoft.com/en-us/dotnet (fetched 2026-08-29T09:10:50.659195+00:00, sha efa9016b58aa)
  - site_page: https://dotnet.microsoft.com/en-us/languages/fsharp/tools (fetched 2026-08-29T09:10:50.664981+00:00, sha e7b78a55955d)
  - site_page: https://dotnet.microsoft.com/en-us/learn/dotnet/what-is-dotnet (fetched 2026-08-29T09:10:50.667120+00:00, sha f9cbdbccc645)
- Data as of 2026-08-30T08:39:29.467469+00:00.