F# excels at building efficient, scalable and robust web solutions. Web programming is based around receiving a single HTTP request and replying with a result, which maps very well to a stateless, functional approach. Advantages to using F# for web programming include:

The Cloud Programming guide contains more details on scalable cloud-hosted web programming with F#.

To contribute to this guide, log on to GitHub, edit this page and send a pull request.

The resources below are listed for educational purposes related to the F# programming language. Mention of commercial products, processes, or services should not be construed as an endorsement or recommendation.

Web Frameworks


Suave is a simple web development F# library providing a lightweight web server and a set of combinators to manipulate route flow and task composition.


Fable is an F# to JS compiler designed to generate clean and standard code in order to maximize interoperability in both ways. It integrates with most of JS development pipelines like Babel, Webpack or React Hot Loader. Fable allows you to develop node.js services, desktop apps with Electron and mobile apps with React native.


ASP.NET Core is a modern, cross-platform, high-performance, open-source framework for building modern, cloud-based, Internet-connected applications. It runs on .NET Core and supports F# out of the box. If you install the .NET Core SDK, there are F# templates available via the dotnet new command.


Giraffe is an F# micro web framework for building rich web applications. It has been heavily inspired and is similar to Suave, but has been specifically designed with ASP.NET Core in mind and can be plugged into the ASP.NET Core pipeline via middleware.


WebSharper allows end-to-end web applications with both client and server developed in F#. It includes TypeScript interoperability, mobile web apps, getting started material, templates and much more.


Freya provides a functional web stack built on top of OWIN. At its core, Freya wraps the OWIN environment dictionary with a computation expression and provides access to that dictionary with lenses. Additional layers of the stack provide types based on the HTTP and related RFCs, a pipeline abstraction for connecting Freya computations, a router, and an implementation of the HTTP finite state machine, like that found in webmachine.


NancyFx is a lightweight, low-ceremony framework for building HTTP-based micro-applications and micro-services on .NET and Mono. F# templates are available.

Serving Requests with IHttpHandler

Do it the simple way, and serve web requests direct from code using F# asynchronous programming.

Serving Requests with Azure Functions

Azure Functions can host and execute F# handlers as micro-services in a serverless architecture,

Pure F# Web API 2.0

Web API 2.0 is a widely used open source web framework from Microsoft. The Pure F# Web Templates (Visual Studio, Web API 2.0). These templates provide a Pure F# project for implementing a web API with Web API 2.0. Everything is implemented in F#.

OWIN and Katana provide a flexible set of components for building and hosting Open Web Interface for .NET (OWIN)-based web applications. Web API can be hosted directly on Katana using the Owin Web API package.

Some resources on using F# with Web API:


SignalR provides bi-directional communication between web servers and clients using one of several mechanisms, beginning with web sockets and falling back through several other approaches depending on client and server capabilities. One example is a Web Application Server (F#).


ServiceStack is a framework for simple and fast web services on .NET and Mono.

ASP.NET Blazor

ASP.NET Blazor is a web framework for running .NET on WebAssembly similar to React, Angular, Vue, etc. It uses Razor .cshtml files to define components and render but can be used with F# libraries.

Bolero is simply another way to bring F# to WebAssembly.

BlazorRedux provides Redux-like state management for Blazor and works well with F#.

Trail provides an F# DSL for rendering in Blazor, allowing for a complete F# solution.

Web Testing Frameworks

Canopy for Client-side Testing

canopy is a web testing framework built on top of selenium and written in F#. It’s syntax is clean and concise. You can easily leverage your existing .NET code to help you test.

Unit Testing Libraries

Some open source libraries that assist with web unit testing are:

Live Examples


TodoBackend is a project that aims to be “a shared example to showcase backend tech stacks.” The F# community has contributed some examples, and a few more are in progress:

Please consider contributing, either directly to the TodoBackend project or via the TodoBackendFSharp project.



Several books have been written that include information on building web applications with F#:


There are several presentations and tutorials available that include information on build web applications with F#:


Common hosting options are:

The resources listed on this page are provided for educational purposes related to the F# programming language. The F# Software Foundation does not endorse or recommend any specific commercial products, processes, or services.