SimpleW

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What is SimpleW? ​

SimpleW is a modern web server for .NET.
It is designed for building fast and secure web applications.

Just want to try it out? Skip to the Quickstart.

Architecture ​

SimpleW’s architecture and the motivations behind its core design choices :

  • Pure C# (100% managed code), running on .NET 8 or later.
  • Built on top of native sockets, low latency.
  • Compiled delegate, close to hard-coded method calls.
  • Custom parser, low memory.
  • Cross‑platform support, Windows/Linux/Android/MacOS.
  • NuGet package available, no dependency, easy to integrate

Philosophy ​

I want to keep the core simple and lightweight so that :

  • The code can be reviewed by a developer in a few hours
  • Or fully ingested (and reasoned about) by an AI in a few seconds

Addons are the place for everything that does not belong in the core. Also, a product is much easier to adopt when there is a healthy ecosystem around it.

Why this library ? ​

Most .NET web stacks are powerful but complex. I wanted a minimal, hackable server that could be dropped into any app, or used as a base for custom frameworks, game servers, or embedded tools — while still delivering very good performances.

But there is more: the .NET environment suffers from a major issue :

There is only one professionally accepted web server. ASP.NET Core is the de facto standard and if you're not using it, you're considered a serious... amateur.

That's a shame ! Not only does an ecosystem need alternatives to grow and improve, but no single product can cover 100% of its users’ needs. I'm certainly not claiming to replace ASP.NET Core or event compete with it, but I want to bring something different in an opinionated way. And I'm not the only one, other devs have done the same :

  • NetCoreServer: still the state of the art in terms of performance and design!
  • Fast-Endpoints: built on top of ASP.NET Core, but with a cleaner and nicer API!
  • GenHTTP: modular at its core, its author supports many engines and contexts!
  • Wired.IO: aims to be the fastest, and it actually is. This one delivers!
  • EmbedIO: no longer maintained, but it was one of the first. A true legacy!

This project ​

SimpleW is the result of years of experimentation, production usage, and frustration with existing solutions. It is a web server designed to be lightweight, explicit, fast and easy to embed.

After 5 years in production, SimpleW:

  • Powers multiple APIs
  • Handles real-world traffic reliably
  • Continues to gain useful features
  • Remains simple and predictable

Final Words ​

If you find a bug, have an idea, or a missing feature — feel free to open an issue.

SimpleW is opinionated, but open.