• toc {:toc}


pow provides local domain names (like http://oxox.dev/). It works by injecting the following things to system:

  • A local DNS server specified in /etc/resolver/dev.
  • A HTTP reverse proxy server to serve pow homepage http://localhost and other applications


  • no more http://localhost:3000.
  • no more editings in /etc/hosts
  • no more rails s


  • OSX only

Install with homebrew

Run brew install pow AND execute what you are instructed.

% brew install pow
Create the required host directories:
  mkdir -p ~/Library/Application\ Support/Pow/Hosts
  ln -s ~/Library/Application\ Support/Pow/Hosts ~/.pow

Setup port 80 forwarding and launchd agents:
  sudo pow --install-system
  pow --install-local

Load launchd agents:
  sudo launchctl load -w /Library/LaunchDaemons/cx.pow.firewall.plist
  launchctl load -w ~/Library/LaunchAgents/cx.pow.powd.plistd.

If this succeeds, you should see a page at http://localhost/.

Run a rails app

I have a rails app in ~/demo_app. The following command register it in pow, so accesses to http://demo_app.dev are routed to it.

The domain name is determined by name of the symlink.

% ln -s ~/demo_app ~/.pow/

Troubles I met

Error: Gem not found

I got Bundler::GemNotFound at first. My GEM_HOME=~/.gem is specified in .zshrc, which is not used by pow and applications it runs.

Fix: add export GEM_HOME=~/.gem to APP_ROOT/.powenv file.

Note: RVM may use more complex env for ruby and gems. They can be generated with rvm env > APP_ROOT/.powenv

See pry manual: Customizing Environment Variables

Got redirected to a search page

demo_app.dev in address bar may be redirected to search page.

Fix: type http://demo_app.dev or demo_app.dev/


Helper gem: powder

powder provides convenient commands to pow.

Restart rails app

Restart once:

touch APP_ROOT/tmp/restart.txt

Restart on each request (does not reload .powrc, .powenv and so on):

touch APP_ROOT/tmp/always_restart.txt
Use pow to host static site

Static sites can also be hosted. The static files should reside in APP_ROOT/public

Use pow as a reverse proxy for non-rails app

This provides localhost:3000 as nanoc.dev:

% echo 3000 > ~/.pow/nanoc

Source: Port proxying

Allow access from other computer

xip.io resolves to So people in same LAN can access the app at demo_app.

More resource

pow wiki @ github

pow manual



prax is an alternative for Linux. It uses:

  • a daemon that runs applications
  • nsswitch trick to take over routing