Gem Version

Want friendly "please upgrade your browser" page? This gem is for you.

You can redirect your visitors to any page you like (static or dynamic). Just specify config.location option in initializer file.


Add following line to your Gemfile:

gem 'browsernizer'

Hook it up:

rails generate browsernizer:install

Configure browser support in config/initializers/browsernizer.rb file.


Initializer file is pretty self explanatory. Here is the default one:

Rails.application.config.middleware.use Browsernizer::Router do |config|
  config.supported "Internet Explorer", "9"
  config.supported "Firefox", "4"
  config.supported "Opera", "11.1"
  config.supported "Chrome", "7"

  config.location  "/browser.html"
  config.exclude   %r{^/assets}

It states that IE9+, FF4+, Opera 11.1+ and Chrome 7+ are supported. Non listed browsers are considered to be supported regardless of their version. Unsupported browsers will be redirected to /browser.html page.

You can specify which paths you wish to exclude with exclude method. It accepts string or regular expression. You can specify multiple paths by calling the config.exclude multiple times.

If you wish to completely prevent some browsers from accessing website (regardless of their version), just set browser version to false.

config.supported "Internet Explorer", false

There is also an option to provide block for more advanced checking. Browser object will be passed to it. If you wish to state that mobile safari is not supported, you can declare it like this:

config.supported do |browser|
  !( == "Safari" &&

The block should return false to block the browser, true to allow it, and nil if it cannot decide. This way you can make any arbitrary User-Agent explicitly allowed, even if its version would have been blocked otherwise:

config.supported do |browser|
  true if'Linux')

Please note, that the order is important, thus the first block or requirement returning a boolean wins.

Specifying location is optional. If you prefer handling unsupported browsers on your own, you can access browsernizer info from request.env['browsernizer'] within your controller.

For example, you can set before filter to display flash notice:

before_filter :check_browser_support

def check_browser_support
  unless request.env['browsernizer']['supported']
    flash.notice = "Your browser is not supported"

You can also access browser and version variables from this env hash.


You should specify browser name as a string. Here are the available options:

  • Chrome
  • Firefox
  • Safari
  • Opera
  • Internet Explorer

And some less popular:

  • Android
  • BlackBerry
  • iPad
  • iPhone
  • iPod Touch
  • PlayStation Portable
  • QuickTime
  • Apple CoreMedia

Browser detection is done using browser gem.

Credits and License

Developed by Milovan Zogovic.

This software is released under the Simplified BSD License.