This extension is part of the Sinatra::Contrib project. Run gem install sinatra-contrib to have it available.


Sinatra::Extension is a mixin that provides some syntactic sugar for your extensions. It allows you to call almost any Sinatra::Base method directly inside your extension module. This means you can use get to define a route, before to define a before filter, set to define a setting and so on.

Is important to be aware that this mixin remembers the method calls you make, and then, when your extension is registered, replays them on the Sinatra application that has been extended. In order to do that, it defines a registered method, so, if your extension defines one too, remember to call super.


Just require the mixin and extend your extension with it:

require 'sinatra/extension'

module MyExtension
  extend Sinatra::Extension

  # set some settings for development
  configure :development do
    set :reload_stuff, true

  # define a route
  get '/' do
    'Hello World'

  # The rest of your extension code goes here...

You can also create an extension with the new method:

MyExtension = do
  # Your extension code goes here...

This is useful when you just want to pass a block to Sinatra::Base.register.