diff --git a/Gemfile b/Gemfile
index bf1f2010d4..0bfd9af374 100644
--- a/Gemfile
+++ b/Gemfile
@@ -14,7 +14,7 @@ gem 'jquery-rails'
 gem 'rails-i18n', ">= 0.6.3"
 gem 'dynamic_form'
 gem 'rinku', '>= 1.2.2', :require => 'rails_rinku'
-gem 'oauth-plugin', '>= 0.4.0.1'
+gem 'oauth-plugin', :git => 'git://github.com/tomhughes/oauth-plugin.git' # while waiting for release of version 0.4.0.1
 gem 'open_id_authentication', '>= 1.1.0'
 gem 'validates_email_format_of', '>= 1.5.1'
 gem 'composite_primary_keys', '>= 5.0.0'
diff --git a/Gemfile.lock b/Gemfile.lock
index c639421584..0e1c11dd15 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,3 +1,13 @@
+GIT
+  remote: git://github.com/tomhughes/oauth-plugin.git
+  revision: 6c929fdc10d00f69743e01c704663f5cdd887a3d
+  specs:
+    oauth-plugin (0.4.0)
+      multi_json
+      oauth (~> 0.4.4)
+      oauth2 (>= 0.5.0)
+      rack
+
 GEM
   remote: http://rubygems.org/
   specs:
@@ -72,11 +82,6 @@ GEM
     multipart-post (1.1.5)
     nokogiri (1.5.2)
     oauth (0.4.6)
-    oauth-plugin (0.4.0.1)
-      multi_json
-      oauth (~> 0.4.4)
-      oauth2 (>= 0.5.0)
-      rack
     oauth2 (0.7.0)
       faraday (~> 0.8)
       httpauth (~> 0.1)
@@ -165,7 +170,7 @@ DEPENDENCIES
   jquery-rails
   libxml-ruby (>= 2.0.5)
   memcached (>= 1.4.1)
-  oauth-plugin (>= 0.4.0.1)
+  oauth-plugin!
   open_id_authentication (>= 1.1.0)
   paperclip (~> 2.0)
   pg
diff --git a/app/controllers/api_controller.rb b/app/controllers/api_controller.rb
index 002bd73b88..602b79d69c 100644
--- a/app/controllers/api_controller.rb
+++ b/app/controllers/api_controller.rb
@@ -2,6 +2,7 @@ class ApiController < ApplicationController
 
   skip_before_filter :verify_authenticity_token
   before_filter :check_api_readable, :except => [:capabilities]
+  before_filter :setup_user_auth, :only => [:permissions]
   after_filter :compress_output
   around_filter :api_call_handle_error, :api_call_timeout
 
@@ -289,4 +290,20 @@ def capabilities
 
     render :text => doc.to_s, :content_type => "text/xml"
   end
+
+  # External apps that use the api are able to query which permissions
+  # they have. This currently returns a list of permissions granted to the current user:
+  # * if authenticated via OAuth, this list will contain all permissions granted by the user to the access_token.
+  # * if authenticated via basic auth all permissions are granted, so the list will contain all permissions.
+  # * unauthenticated users have no permissions, so the list will be empty.
+  def permissions
+    @permissions = case
+                   when current_token.present?
+                     ClientApplication.all_permissions.select { |p| current_token.read_attribute(p) }
+                   when @user
+                     ClientApplication.all_permissions
+                   else
+                     []
+                   end
+  end
 end
diff --git a/app/views/api/permissions.builder b/app/views/api/permissions.builder
new file mode 100644
index 0000000000..066f567887
--- /dev/null
+++ b/app/views/api/permissions.builder
@@ -0,0 +1,9 @@
+# create list of permissions
+xml.instruct! :xml, :version=>"1.0"
+xml.osm("version" => "#{API_VERSION}", "generator" => "OpenStreetMap Server") do
+  xml.permissions do
+    @permissions.each do |permission|
+      xml.permission :name => permission
+    end
+  end
+end
diff --git a/config/routes.rb b/config/routes.rb
index bc4c12c972..c24ba05e31 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -2,6 +2,7 @@
   # API
   match 'api/capabilities' => 'api#capabilities', :via => :get
   match 'api/0.6/capabilities' => 'api#capabilities', :via => :get
+  match 'api/0.6/permissions' => 'api#permissions', :via => :get
 
   match 'api/0.6/changeset/create' => 'changeset#create', :via => :put
   match 'api/0.6/changeset/:id/upload' => 'changeset#upload', :via => :post, :id => /\d+/
diff --git a/test/functional/api_controller_test.rb b/test/functional/api_controller_test.rb
index adc433fe07..ae3817f1a2 100644
--- a/test/functional/api_controller_test.rb
+++ b/test/functional/api_controller_test.rb
@@ -298,4 +298,42 @@ def test_capabilities
       end
     end
   end
+
+  def test_permissions_anonymous
+    get :permissions
+    assert_response :success
+    assert_select "osm > permissions", :count => 1 do
+      assert_select "permission", :count => 0
+    end
+  end
+
+  def test_permissions_basic_auth
+    basic_authorization(users(:normal_user).email, "test")
+    get :permissions
+    assert_response :success
+    assert_select "osm > permissions", :count => 1 do
+      assert_select "permission", :count => ClientApplication.all_permissions.size
+      ClientApplication.all_permissions.each do |p|
+        assert_select "permission[name=#{p}]", :count => 1
+      end
+    end
+  end
+
+  def test_permissions_oauth
+    @token =  AccessToken.new do |token|
+      # Just to test a few
+      token.allow_read_prefs = true
+      token.allow_write_api = true
+      token.allow_read_gpx = false
+    end
+    @request.env["oauth.token"] = @token
+    get :permissions
+    assert_response :success
+    assert_select "osm > permissions", :count => 1 do
+      assert_select "permission", :count => 2
+      assert_select "permission[name=allow_read_prefs]", :count => 1
+      assert_select "permission[name=allow_write_api]", :count => 1
+      assert_select "permission[name=allow_read_gpx]", :count => 0
+    end
+  end
 end