Redirect traffic addressed to any host at any port to any IP and port.

Usage no npm install needed!

<script type="module">
  import rdr from 'https://cdn.skypack.dev/rdr';



Simulate multi-server production environments on your Mac, with multiple projects handling traffic on the same ports simultaneously (e.g., 80, 443).

Install it.

You'll want to install rdr globally, so you can use the executable from the command line (it would be of little use as a local project dependency).

sudo npm install rdr -g

N.b.: rdr is not tested on versions of OSX prior to 10.11 (El Capitan). In 10.10.5 (Yosemite), it works in Chrome/FF, but is unreliable in Safari.

Use it.

Configure .rdr

While you do not need to have a configuration file to use rdr, doing so makes it easier to manage many redirect rules, especially if you need special environments for multiple projects.

For each project needing domain+port forwarding, provide an .rdr configuration file in project root. The syntax is self-explanatory (comments are bash-style):

project.com:80 to
internal.project.com:80 to
api.project.com:80 to


  • rdr . to consume $cwd/.rdr (clobbers previous configuration)
  • rdr on to enable
  • rdr off to disable
  • rdr list to inspect the configuration
  • rdr reset to empty the current configuration
  • rdr restore to overwrite /etc/hosts with ~/.etchosts.bak
  • rdr <host>:<port-x> to <ip>:<port-y> (clobbers previous configuration)
  • rdr --version
  • rdr --help

About your browser:

Browsers store DNS information and keep sockets open across page loads, so you'll need to clear that stuff occasionally, after using rdr on or rdr off.

Chrome users may need to use chrome://internals/#dns and /#sockets to flush DNS and the socket pool. The console prints a reminder.

Safari users may have to wait a moment and/or refresh the page a few times.