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:

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Integrated Stacks

SAFE Stack

logo SAFE Stack is an end-to-end, functional-first stack for cloud-ready web development that emphasizes type-safe programming. It is an application development stack that brings several technologies together into a single, coherent stack for type-safe, flexible, web-enabled applications that can be written almost entirely in F#.


WebSharper

logo 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.


Fable

logo 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.

Web Frameworks


Giraffe

logo Giraffe is an F# library for building rich web applications that use ASP.NET Core under the hood. 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.


ASP.NET Core

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.


Suave

logo 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.


Saturn

logo Saturn is a web development framework written in F# which implements the server-side MVC pattern. Many of its components and concepts will seem familiar to anyone with experience in other web frameworks like Ruby on Rails or Python’s Django. It’s built on top of Giraffe and ASP.Net Core - modern, cross-platform, high-performance development platform for building cloud-ready web applications.

It’s heavily inspired by Elixir’s Phoenix.


Bolero

logo Bolero - F# on the client side, no JavaScript - Bolero uses Blazor to bring F# to WebAssembly. Create dynamic HTML content using syntax familiar from WebSharper and Fable, in a full-fledged client-side .NET web framework.


Serving Requests with IHttpHandler

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


SignalR

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#).


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.


NancyFx

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


Freya

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.


ServiceStack

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



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

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.


Tutorials


Books

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


Presentations

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


Hosting

Common hosting options are: