diff --git a/.gitignore b/.gitignore
index c1e0dafa8d..48fe6d6124 100644
--- a/.gitignore
+++ b/.gitignore
@@ -17,5 +17,7 @@ tmtags
 coverage
 rdoc
 pkg
+.rvmrc
+.bundle
 
 ## PROJECT::SPECIFIC
diff --git a/Gemfile b/Gemfile
index a5f105cec6..183e28ea34 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,6 +2,9 @@ gem 'rack'
 gem 'rack-mount'
 gem 'rack-jsonp'
 
+gem 'json'
+gem 'multi_json'
+
 group :test do
   gem 'rspec', '>= 2.0.0.beta.19'
   gem 'rack-test'
diff --git a/Gemfile.lock b/Gemfile.lock
index edd1a8a368..252e3678b6 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -10,7 +10,9 @@ GEM
     diff-lcs (1.1.2)
     gherkin (2.1.5)
       trollop (~> 1.16.2)
+    json (1.4.3)
     json_pure (1.4.3)
+    multi_json (0.0.4)
     rack (1.2.1)
     rack-jsonp (1.0.0)
     rack-mount (0.6.9)
@@ -33,6 +35,8 @@ PLATFORMS
 
 DEPENDENCIES
   cucumber (>= 0.8.5)
+  json
+  multi_json
   rack
   rack-jsonp
   rack-mount
diff --git a/Rakefile b/Rakefile
index 9ec72c44f6..6a44721f7f 100644
--- a/Rakefile
+++ b/Rakefile
@@ -10,6 +10,8 @@ begin
     gem.email = "michael@intridea.com"
     gem.homepage = "http://github.com/intridea/grape"
     gem.authors = ["Michael Bleigh"]
+    gem.add_dependency 'rack'
+    gem.add_dependency 'multi_json'
     gem.add_development_dependency "rspec", ">= 1.2.9"
     gem.add_development_dependency "cucumber", ">= 0"
     # gem is a Gem::Specification... see http://www.rubygems.org/read/chapter/20 for additional settings
diff --git a/lib/grape.rb b/lib/grape.rb
index 75d2f8c25e..fc11937db2 100644
--- a/lib/grape.rb
+++ b/lib/grape.rb
@@ -3,4 +3,5 @@
 
 require 'grape/middleware/base'
 require 'grape/middleware/prefixer'
-require 'grape/middleware/versioner'
\ No newline at end of file
+require 'grape/middleware/versioner'
+require 'grape/middleware/formatter'
\ No newline at end of file
diff --git a/lib/grape/middleware/error.rb b/lib/grape/middleware/error.rb
new file mode 100644
index 0000000000..429fd37136
--- /dev/null
+++ b/lib/grape/middleware/error.rb
@@ -0,0 +1,9 @@
+require 'grape/middleware/base'
+
+module Grape
+  module Middleware
+    class Error < Base
+      
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/grape/middleware/formatter.rb b/lib/grape/middleware/formatter.rb
new file mode 100644
index 0000000000..175969f9f1
--- /dev/null
+++ b/lib/grape/middleware/formatter.rb
@@ -0,0 +1,60 @@
+require 'grape/middleware/base'
+require 'multi_json'
+
+module Grape
+  module Middleware
+    class Formatter < Base
+      CONTENT_TYPES = {
+        :xml => 'application/xml',
+        :json => 'application/json',
+        :atom => 'application/atom+xml',
+        :rss => 'application/rss+xml'
+      }
+      
+      def default_options
+        { 
+          :default_format => :json,
+          :content_types => {}
+        }
+      end
+      
+      def content_types
+        CONTENT_TYPES.merge(options[:content_types])
+      end
+      
+      def before
+        fmt = format_from_extension || format_from_header || options[:default_format]
+        
+        if content_types.key?(fmt)
+          env['api.format'] = fmt          
+        else
+          env['api.error.status'] = 406
+          env['api.error.message'] = 'The requested format is not supported.'
+        end
+      end
+      
+      def format_from_extension
+        parts = request.path.split('.')
+        hit = parts.last.to_sym
+        
+        if parts.size <= 1
+          nil
+        else
+          hit
+        end
+      end
+      
+      def format_from_header
+        # TODO: Implement Accept header parsing.
+      end
+      
+      def after
+        status, headers, bodies = *@app_response
+        bodies.map! do |body|
+          MultiJson.encode(body)
+        end
+        [status, headers, bodies]
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/grape/middleware/error_spec.rb b/spec/grape/middleware/error_spec.rb
new file mode 100644
index 0000000000..a25bb28ed5
--- /dev/null
+++ b/spec/grape/middleware/error_spec.rb
@@ -0,0 +1,5 @@
+require 'spec_helper'
+
+describe Grape::Middleware::Error do
+  
+end
\ No newline at end of file
diff --git a/spec/grape/middleware/formatter_spec.rb b/spec/grape/middleware/formatter_spec.rb
new file mode 100644
index 0000000000..bde7319c02
--- /dev/null
+++ b/spec/grape/middleware/formatter_spec.rb
@@ -0,0 +1,35 @@
+require 'spec_helper'
+
+describe Grape::Middleware::Formatter do
+  subject{ Grape::Middleware::Formatter.new(app)}
+  before{ subject.stub!(:dup).and_return(subject) }
+  
+  let(:app){ lambda{|env| [200, {}, [@body]]} }
+  
+  context 'serialization' do
+    it 'should look at the bodies for possibly serializable data' do
+      @body = {"abc" => "def"}
+      status, headers, bodies = *subject.call({'PATH_INFO' => '/somewhere'})
+      bodies.first.should == MultiJson.encode(@body)
+    end
+  end
+  
+  context 'detection' do
+    it 'should use the extension if one is provided' do
+      subject.call({'PATH_INFO' => '/info.xml'})
+      subject.env['api.format'].should == :xml
+      subject.call({'PATH_INFO' => '/info.json'})
+      subject.env['api.format'].should == :json
+    end
+    
+    it 'should use the default format if none is provided' do
+      subject.call({'PATH_INFO' => '/info'})
+      subject.env['api.format'].should == :json
+    end
+    
+    it 'should throw an error on an unrecognized format' do
+      subject.call({'PATH_INFO' => '/info.barklar'})
+      subject.env['api.error.status'].should == 406
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 7874c56f62..47a03ac529 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -5,11 +5,11 @@
 
 require 'rubygems'
 require 'bundler'
-Bundler.setup :test
+Bundler.setup :default, :test
 
 require 'rspec'
 require 'rack/test'
 
 RSpec.configure do |config|
-  
+  config.include Rack::Test::Methods
 end