created_at2020-09-23 10:01:14.71813
updated_at2020-09-23 10:01:14.71813
descriptionLanguage-agnostic, simple-to-use development server, file-watcher and tiny build system mainly useful for webdev.
Lukas Kalbertodt (LukasKalbertodt)




CI status of master Crates.io Version Crates.io Downloads

Floof is a language and tech-stack agnostic, simple-to-use development server, file-watcher and tiny build system. It is mainly useful for web-development (i.e. where you inspect your software in the browser) due to its ability to automatically reload your app in the browser. For other projects, cargo watch or watchexec might be better suited (and those are way more mature).


  • Run arbitrary commands

  • Watch for file changes (with debouncing)

  • Automatically reload the page in your browser

  • HTTP server

    • Reverse-proxy (usually to your backend application)
    • Inject JS code for "auto reload"
    • Static file server
  • Tiny build-system

  • Platform-independent file system operations (copy, ...)

  • Templates to support zero-configuration use in some situations


Currently the best way is to install from crates.io. You need Rust and Cargo to do that, as you compile the application yourself.

cargo install floof

At some point I will start attaching pre-compiled binaries to the GitHub releases.


A floof.yaml is expected in the root folder of the project/in the directory you run floof in (like Makefile). That file defines what actions need to be run and configures a bunch of other stuff. The following is an example for a simple project that uses a Rust backend server that serves HTML and listens on port 3030.

  - concurrently:
    - http:
    - watch:
          - Cargo.toml
          - Cargo.lock
          - src/
          - reload:      # This will wait for port 3030 to become available
          - cargo run    # This long running command is killed on file changes

When running floof in that directory, the output looks something like this:

════════════╡    [default][http] Listening on
════════════╡ ▶️  [default][command] running: cargo run
   Compiling floof-example v0.0.0
    Finished dev [unoptimized + debuginfo] target(s) in 2.21s
     Running `target/debug/floof-example`

... output from your server application ...

════════════╡ ♻️  [default][http] Reloading all active sessions

You are then supposed to open localhost:8030 in your browser. This will show exactly the same as your actual backend server (which is listening on localhost:3030) as floof works as a reverse proxy. However, floof injects a small JS snippet responsible for automatically reloading the page in your browser once something changes. This snippet communicates with floof via web sockets.

When changing a file:

════════════╡ 🛑 [default][watch] change detected while executing operations! Cancelling operations, then debouncing for 500ms...
════════════╡ 🔥 [default][watch] change detected: running all operations...
════════════╡ ▶️  [default][command] running: cargo run

... output from your server application ...

════════════╡ ♻️  [default][http] Reloading all active sessions

Status of this project

This project is really young and lots of stuff might still break! A lot of features are missing as well. I only started this project to help with developing another project I am working on.


Licensed under either of Apache License, Version 2.0 or MIT license at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this project by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.
Commit count: 97

cargo fmt