2 stable releases

Uses old Rust 2015

3.0.1 Apr 12, 2021

#918 in HTTP server


5.5K SLoC

Rouille NG

rouille-ng is a maintenance fork of Rouille,

Rouille is a micro-web-framework library. It creates a listening socket and parses incoming HTTP requests from clients, then gives you the hand to process the request.

Rouille was designed to be intuitive to use if you know Rust. Contrary to express-like frameworks, it doesn't employ middlewares. Instead everything is handled in a linear way.

Concepts closely related to websites (like cookies, CGI, form input, etc.) are directly supported by rouille. More general concepts (like database handling or templating) are not directly handled, as they are considered orthogonal to the micro web framework. However rouille's design makes it easy to use in conjunction with any third-party library without the need for any glue code.


What's with Rouille NG?

The original Rouille project has been unmaintained for over a year, and it seems unlikely to become active again soon. Rouille NG is intended to support teams using Rouille in production with security fixes and quality of life improvements, while retaining API compatibility with the original library.


  • Maintain drop-in compatibility with Rouille 3.0.0
  • Maintain the codebase vis-à-vis deprecation or compiler warnings introduced by new Rust versions.
  • Support a minimum Rust version equal to that shipped with Debian Stable (currently 1.41).
  • Backport security fixes to 3.0.y releases.
  • Add non-breaking QoL improvements to 3.x releases.

Community contributions in line with these goals are welcome!

Getting started

If you have general knowledge about how HTTP works, the documentation and the well-documented examples are good resources to get you started.

You can swap your dependency on Rouille for Rouille NG by adding the following to your Cargo.toml

rouille = { package = "rouille-ng", version = "3" }


Licensed under either of


Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you shall be dual licensed as above, without any additional terms or conditions.


What about performances?

Async I/O, green threads, coroutines, etc. in Rust are still very immature.

The rouille library just ignores this optimization and focuses on providing an easy-to-use synchronous API instead, where each request is handled in its own dedicated thread.

Even if rouille itself was asynchronous, you would need asynchronous database clients and asynchronous file loading in order to take advantage of it. There are currently no such libraries in the Rust ecosystem.

Once async I/O has been figured out, rouille will be (hopefully transparently) updated to take it into account.

But is it fast?

On the author's old Linux machine, some basic benchmarking with wrk -t 4 -c 4 shows the following results:

  • The hello-world example of rouille yields ~22k requests/sec.
  • A hello world in nodejs (with http.createServer) yields ~14k requests/sec.
  • The hello-world example of tokio-minihttp (which is supposedly the fastest HTTP server that currently exists) yields ~77k requests/sec.
  • The hello example of hyper (which uses async I/O with mio as well) yields ~53k requests/sec.
  • A hello world in Go yields ~51k requests/sec.
  • The default installation of nginx yields ~39k requests/sec.

While not the fastest, rouille has reasonable performances. Amongst all these examples, rouille is the only one to use synchronous I/O.

Are there plugins for features such as database connection, templating, etc.

It should be trivial to integrate a database or templates to your web server written with rouille. Moreover plugins need maintenance and tend to create a dependency hell. In the author's opinion it is generally better not to use plugins.

But I'm used to express-like frameworks!

Instead of doing this: (pseudo-code)

server.add_middleware(function() {
    // middleware 1

server.add_middleware(function() {
    // middleware 2

server.add_middleware(function() {
    // middleware 3

In rouille you just handle each request entirely manually:

// initialize everything here

rouille::start_server(..., move |request| {
    // middleware 1

    // middleware 2

    // middleware 3


~270K SLoC