diff --git a/.bowerrc b/.bowerrc
index 6e57b2ec9d..3f8ac64455 100644
--- a/.bowerrc
+++ b/.bowerrc
@@ -1,3 +1,3 @@
 {
-  "directory" : "www/assets"
+    "directory" : "assets"
 }
diff --git a/.gitignore b/.gitignore
index 56f96c7332..533fa65a97 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,4 +15,5 @@ composer.phar
 behat.yml
 /datas
 /www/assets
+/assets
 /www/skins/build
diff --git a/Gruntfile.js b/Gruntfile.js
new file mode 100644
index 0000000000..7945faff60
--- /dev/null
+++ b/Gruntfile.js
@@ -0,0 +1,228 @@
+module.exports = function(grunt) {
+    grunt.initConfig({
+        clean: {
+            "assets": ["assets", "www/assets"],
+        },
+        bower: {
+            install: {
+                options: {
+                    "copy": false
+                }
+            }
+        },
+        bower_postinst: {
+            dist: {
+                options: {
+                    components: {
+                        "jquery.ui": ["npm", {"grunt": "build"}],
+                        "bootstrap": ["npm", {"make": "bootstrap"}]
+                    }
+                }
+            }
+        },
+        copy: {
+            "backbone": {
+                "expand": true,
+                "src": [
+                    "assets/backbone-amd/LICENSE",
+                    "assets/backbone-amd/backbone.js"
+                ],
+                "dest": "www/assets/backbone-amd/",
+                "flatten": true
+            },
+            "blueimp": {
+                "expand": true,
+                "src": ["js/load-image.js", "css/jquery.fileupload-ui.css"],
+                "dest": "www/assets/blueimp-load-image/",
+                "cwd": "assets/blueimp-load-image"
+            },
+            "bootstrap": {
+                "expand": true,
+                "cwd": "assets/bootstrap",
+                "src": [
+                    "bootstrap/css/*",
+                    "bootstrap/js/*",
+                    "bootstrap/img/*",
+                    "LICENSE"
+                ],
+                "rename": function(dest, src) {
+                    return dest + src.replace("bootstrap", "");
+                },
+                "dest": "www/assets/bootstrap/"
+            },
+            "bootstrap-multiselect": {
+                "expand": true,
+                "cwd": "assets/bootstrap-multiselect",
+                "src": [
+                    "css/bootstrap-multiselect.css",
+                    "js/bootstrap-multiselect.js",
+                ],
+                "dest": "www/assets/bootstrap-multiselect/"
+            },
+            "chai": {
+                "expand": true,
+                "src": "assets/chai/chai.js",
+                "dest": "www/assets/chai/",
+                "flatten": true
+            },
+            "font-awesome": {
+                "expand": true,
+                "cwd": "assets/font-awesome",
+                "src": ["css/*", "font/*"],
+                "dest": "www/assets/font-awesome/"
+            },
+            "geonames-server-jquery-plugin": {
+                "expand": true,
+                "flatten": true,
+                "src": [
+                    "assets/geonames-server-jquery-plugin/LICENSE",
+                    "assets/geonames-server-jquery-plugin/jquery.geonames.js"
+                ],
+                "dest": "www/assets/geonames-server-jquery-plugin"
+            }
+            ,
+            "humane-js": {
+                "expand": true,
+                "src": ["humane.js", "themes/libnotify.css"],
+                "dest": "www/assets/humane-js/",
+                "cwd": "assets/humane-js/"
+            },
+            "i18next": {
+                "expand": true,
+                "src": "assets/i18next/release/i18next.amd-1.6.3.js",
+                "dest": "www/assets/i18next/",
+                "flatten": true
+            },
+            "jquery": {
+                "expand": true,
+                "src": "assets/jquery/jquery.js",
+                "dest": "www/assets/jquery/",
+                "flatten": true
+            },
+            "jquery-file-upload": {
+                "expand": true,
+                "src": [
+                    "assets/jquery-file-upload/js/jquery.fileupload.js",
+                    "assets/jquery-file-upload/js/jquery.iframe-transport.js"
+                ],
+                "dest": "www/assets/jquery-file-upload/",
+                "flatten": true
+            },
+            "jquery-ui": {
+                "expand": true,
+                "cwd": "assets/jquery.ui/dist",
+                "src": [
+                    "i18n/*",
+                    "images/*",
+                    "themes/*",
+                    "jquery-ui.css",
+                    "jquery-ui.js"
+                ],
+                "dest": "www/assets/jquery.ui/"
+            },
+            "js-fixture": {
+                "expand": true,
+                "src": [
+                    "assets/js-fixtures/LICENSE",
+                    "assets/js-fixtures/fixtures.js"
+                ],
+                "dest": "www/assets/js-fixture/",
+                "flatten": true
+            },
+            "json3": {
+                "expand": true,
+                "src": [
+                    "assets/json3/LICENSE",
+                    "assets/json3/lib/json3.js"
+                ],
+                "dest": "www/assets/json3/",
+                "flatten": true
+            },
+            "mocha": {
+                "expand": true,
+                "src": [
+                    "assets/mocha/LICENSE",
+                    "assets/mocha/mocha.js",
+                    "assets/mocha/mocha.css"
+                ],
+                "dest": "www/assets/mocha/",
+                "flatten": true
+            },
+            "modernizr": {
+                "expand": true,
+                "src": "assets/modernizr/modernizr.js",
+                "dest": "www/assets/modernizr/",
+                "flatten": true
+            },
+            "normalize": {
+                "expand": true,
+                "src": [
+                    "assets/normalize-css/normalize.css",
+                    "assets/normalize-css/LICENSE.md"
+                ],
+                "dest": "www/assets/normalize-css/",
+                "flatten": true
+            },
+            "qunit": {
+                "expand": true,
+                "src": [
+                    "assets/qunit/qunit/qunit.css",
+                    "assets/qunit/qunit/qunit.js"
+                ],
+                "dest": "www/assets/qunit/",
+                "flatten": true
+            },
+            "requirejs": {
+                "expand": true,
+                "src": [
+                    "assets/requirejs/LICENSE",
+                    "assets/requirejs/require.js"
+                ],
+                "dest": "www/assets/requirejs/",
+                "flatten": true
+            },
+            "underscore": {
+                "expand": true,
+                "src": [
+                    "assets/underscore-amd/LICENSE",
+                    "assets/underscore-amd/underscore.js"
+                ],
+                "dest": "www/assets/underscore-amd/",
+                "flatten": true
+            },
+            "zxcvbn": {
+                "expand": true,
+                "src": [
+                    "assets/zxcvbn/LICENSE.txt",
+                    "assets/zxcvbn/zxcvbn-async.js"
+                ],
+                "dest": "www/assets/zxcvbn",
+                "flatten": true
+            }
+        },
+        less: {
+            login: {
+                options: {
+                    paths: ["www/skins/login/less"],
+                },
+                files: {
+                    "www/assets/build/login.css": "www/skins/login/less/login.less"
+                }
+            },
+            account: {
+                options: {
+                    paths: ["www/skins/account"],
+                },
+                files: {
+                    "www/assets/build/account.css": "www/skins/account/account.less"
+                }
+            },
+        }
+    });
+
+    grunt.loadNpmTasks("grunt-contrib");
+    grunt.loadNpmTasks("grunt-bower-task");
+    grunt.loadNpmTasks("grunt-bower-postinst");
+
+    grunt.registerTask("build-assets", ["clean:assets", "bower", "bower_postinst", "copy", "less"]);
+};
diff --git a/bower.json b/bower.json
index 6755db22a7..2e4aa507e3 100644
--- a/bower.json
+++ b/bower.json
@@ -6,7 +6,6 @@
     "jquery": "~1.8.3",
     "jquery.ui": "~1.10.0",
     "font-awesome": "~3.0.2",
-    "underscore": "~1.4.4",
     "modernizr": "~2.6.2",
     "normalize-css" : "~2.1.0",
     "json3" : "3.2.4",
@@ -20,8 +19,6 @@
     "mocha": "~1.9",
     "chai" : "~1.6",
     "i18next": "~1.6",
-    "sinon": "~1.7",
-    "sinon-chai": "~2.4",
     "js-fixtures": "https://github.com/badunk/js-fixtures/archive/master.zip",
     "bootstrap-multiselect": "https://github.com/davidstutz/bootstrap-multiselect.git",
     "zxcvbn" : "https://github.com/lowe/zxcvbn.git",
diff --git a/builder.php b/builder.php
index b7e401ef47..b926eb41e2 100755
--- a/builder.php
+++ b/builder.php
@@ -93,6 +93,7 @@ $finder
     ->name('sinon-chai')
     ->name('js-fixtures')
     ->name('node_modules')
+    ->name('assets')
     ->ignoreDotFiles(false)
     ->ignoreVCS(false)
     ->in(__DIR__);
diff --git a/lib/conf.d/minifyGroupsConfig.php b/lib/conf.d/minifyGroupsConfig.php
index 983ce92163..6cb5e73d92 100644
--- a/lib/conf.d/minifyGroupsConfig.php
+++ b/lib/conf.d/minifyGroupsConfig.php
@@ -46,9 +46,9 @@ $groups = array(
         , '//include/jquery.common.js'
         , '//include/jquery.tooltip.js'
         , '//include/jslibs/jquery.contextmenu_scroll.js'
-        , '//assets/blueimp-load-image/js/load-image.js'
-        , '//assets/jquery-file-upload/js/jquery.iframe-transport.js'
-        , '//assets/jquery-file-upload/js/jquery.fileupload.js'
+        , '//assets/blueimp-load-image/load-image.js'
+        , '//assets/jquery-file-upload/jquery.iframe-transport.js'
+        , '//assets/jquery-file-upload/jquery.fileupload.js'
     ),
     'report' => array(
          '//include/jslibs/jquery-ui-1.10.3/jquery-ui-i18n.js'
@@ -76,9 +76,9 @@ $groups = array(
         , '//include/jslibs/jquery.cookie.js'
         , '//include/jquery.common.js'
         , '//assets/humane-js/humane.js'
-        , '//assets/blueimp-load-image/js/load-image.js'
-        , '//assets/jquery-file-upload/js/jquery.iframe-transport.js'
-        , '//assets/jquery-file-upload/js/jquery.fileupload.js'
+        , '//assets/blueimp-load-image/load-image.js'
+        , '//assets/jquery-file-upload/jquery.iframe-transport.js'
+        , '//assets/jquery-file-upload/jquery.fileupload.js'
         , '//include/jslibs/jquery.form.2.49.js'
         , '//include/jslibs/jquery.vertical.buttonset.js'
         , '//include/js/jquery.Selection.js'
diff --git a/package.json b/package.json
index 93c8319518..b60722df6b 100644
--- a/package.json
+++ b/package.json
@@ -6,6 +6,10 @@
         "mocha-phantomjs": ">=2.0 <3.0",
         "recess": ">=1.1.0 <1.1.7",
         "uglify-js": "latest",
-        "phantomjs": "latest"
+        "phantomjs": "latest",
+        "grunt": "~0.4.1",
+        "grunt-contrib": "latest",
+        "grunt-bower-task": "latest",
+        "grunt-bower-postinst": "latest"
     }
 }
diff --git a/templates/web/common/index_bootstrap.html.twig b/templates/web/common/index_bootstrap.html.twig
index e27232ceb0..fca7cafab7 100644
--- a/templates/web/common/index_bootstrap.html.twig
+++ b/templates/web/common/index_bootstrap.html.twig
@@ -12,7 +12,7 @@
 
         <!--[if lte IE 8]>
             <link rel="stylesheet" href="{{ path('minifier', { 'f' : 'assets/font-awesome/css/font-awesome-ie7.min.css' }) }}">
-            <script type="text/javascript" src="{{ path('minifier', {'f' : 'assets/json3/lib/json3.js'}) }}"></script>
+            <script type="text/javascript" src="{{ path('minifier', {'f' : 'assets/json3/json3.js'}) }}"></script>
         <![endif]-->
 
         <script type="text/javascript" src="{{ path('minifier', { 'f' : 'assets/jquery/jquery.js' }) }}"></script>
diff --git a/templates/web/login/layout/base-layout.html.twig b/templates/web/login/layout/base-layout.html.twig
index 96a9badeff..18724e83c9 100644
--- a/templates/web/login/layout/base-layout.html.twig
+++ b/templates/web/login/layout/base-layout.html.twig
@@ -36,7 +36,7 @@
 
             {% block header_javascript %}
                  <!--[if lte IE 8]>
-                    <script type="text/javascript" src="{{ path('minifier', {'f' : 'assets/json3/lib/json3.js'}) }}"></script>
+                    <script type="text/javascript" src="{{ path('minifier', {'f' : 'assets/json3/json3.js'}) }}"></script>
                 <![endif]-->
 
                 {# include backbone templates #}
diff --git a/www/skins/account/account.less b/www/skins/account/account.less
index b2d346b460..1e45359942 100644
--- a/www/skins/account/account.less
+++ b/www/skins/account/account.less
@@ -1,61 +1,61 @@
 // CSS Reset
-@import "../../assets/bootstrap/less/reset.less";
+@import "../../../assets/bootstrap/less/reset.less";
 
 // Core variables and mixins
-@import "../../assets/bootstrap/less/variables.less";
+@import "../../../assets/bootstrap/less/variables.less";
 @import "variables.less";
 @import "../../../plugins/account.less";
-@import "../../assets/bootstrap/less/mixins.less";
+@import "../../../assets/bootstrap/less/mixins.less";
 
 // Grid system and page structure
-@import "../../assets/bootstrap/less/scaffolding.less";
-@import "../../assets/bootstrap/less/grid.less";
-@import "../../assets/bootstrap/less/layouts.less";
+@import "../../../assets/bootstrap/less/scaffolding.less";
+@import "../../../assets/bootstrap/less/grid.less";
+@import "../../../assets/bootstrap/less/layouts.less";
 
 // Base CSS
-@import "../../assets/bootstrap/less/type.less";
-@import "../../assets/bootstrap/less/code.less";
-@import "../../assets/bootstrap/less/forms.less";
-@import "../../assets/bootstrap/less/tables.less";
+@import "../../../assets/bootstrap/less/type.less";
+@import "../../../assets/bootstrap/less/code.less";
+@import "../../../assets/bootstrap/less/forms.less";
+@import "../../../assets/bootstrap/less/tables.less";
 
 // Components: common
-@import "../../assets/bootstrap/less/sprites.less";
-@import "../../assets/bootstrap/less/dropdowns.less";
-@import "../../assets/bootstrap/less/wells.less";
-@import "../../assets/bootstrap/less/component-animations.less";
-@import "../../assets/bootstrap/less/close.less";
+@import "../../../assets/bootstrap/less/sprites.less";
+@import "../../../assets/bootstrap/less/dropdowns.less";
+@import "../../../assets/bootstrap/less/wells.less";
+@import "../../../assets/bootstrap/less/component-animations.less";
+@import "../../../assets/bootstrap/less/close.less";
 
 // Components: Buttons & Alerts
-@import "../../assets/bootstrap/less/buttons.less";
-@import "../../assets/bootstrap/less/button-groups.less";
-@import "../../assets/bootstrap/less/alerts.less"; // Note: alerts share common CSS with buttons and thus have styles in buttons.less
+@import "../../../assets/bootstrap/less/buttons.less";
+@import "../../../assets/bootstrap/less/button-groups.less";
+@import "../../../assets/bootstrap/less/alerts.less"; // Note: alerts share common CSS with buttons and thus have styles in buttons.less
 
 // Components: Nav
-@import "../../assets/bootstrap/less/navs.less";
-@import "../../assets/bootstrap/less/navbar.less";
-@import "../../assets/bootstrap/less/breadcrumbs.less";
-@import "../../assets/bootstrap/less/pagination.less";
-@import "../../assets/bootstrap/less/pager.less";
+@import "../../../assets/bootstrap/less/navs.less";
+@import "../../../assets/bootstrap/less/navbar.less";
+@import "../../../assets/bootstrap/less/breadcrumbs.less";
+@import "../../../assets/bootstrap/less/pagination.less";
+@import "../../../assets/bootstrap/less/pager.less";
 
 // Components: Popovers
-@import "../../assets/bootstrap/less/modals.less";
-@import "../../assets/bootstrap/less/tooltip.less";
-@import "../../assets/bootstrap/less/popovers.less";
+@import "../../../assets/bootstrap/less/modals.less";
+@import "../../../assets/bootstrap/less/tooltip.less";
+@import "../../../assets/bootstrap/less/popovers.less";
 
 // Components: Misc
-@import "../../assets/bootstrap/less/thumbnails.less";
-@import "../../assets/bootstrap/less/media.less";
-@import "../../assets/bootstrap/less/labels-badges.less";
-@import "../../assets/bootstrap/less/progress-bars.less";
-@import "../../assets/bootstrap/less/accordion.less";
-@import "../../assets/bootstrap/less/carousel.less";
-@import "../../assets/bootstrap/less/hero-unit.less";
+@import "../../../assets/bootstrap/less/thumbnails.less";
+@import "../../../assets/bootstrap/less/media.less";
+@import "../../../assets/bootstrap/less/labels-badges.less";
+@import "../../../assets/bootstrap/less/progress-bars.less";
+@import "../../../assets/bootstrap/less/accordion.less";
+@import "../../../assets/bootstrap/less/carousel.less";
+@import "../../../assets/bootstrap/less/hero-unit.less";
 
 // Utility classes
-@import "../../assets/bootstrap/less/utilities.less"; // Has to be last to override when necessary
+@import "../../../assets/bootstrap/less/utilities.less"; // Has to be last to override when necessary
 
 // Responsive
-@import "../../assets/bootstrap/less/responsive.less";
+@import "../../../assets/bootstrap/less/responsive.less";
 @import "variables.less";
 @import "../../../plugins/account.less";
 
diff --git a/www/skins/login/less/login.less b/www/skins/login/less/login.less
index 51a0246475..9fe8f61674 100644
--- a/www/skins/login/less/login.less
+++ b/www/skins/login/less/login.less
@@ -1,63 +1,63 @@
 // CSS Reset
-@import "../../../assets/bootstrap/less/reset.less";
+@import "../../../../assets/bootstrap/less/reset.less";
 
 // Core variables and mixins
-@import "../../../assets/bootstrap/less/variables.less";
+@import "../../../../assets/bootstrap/less/variables.less";
 
 @import "variables.less";
 @import "../../../../plugins/login.less";
 
-@import "../../../assets/bootstrap/less/mixins.less";
+@import "../../../../assets/bootstrap/less/mixins.less";
 
 // Grid system and page structure
-@import "../../../assets/bootstrap/less/scaffolding.less";
-@import "../../../assets/bootstrap/less/grid.less";
-@import "../../../assets/bootstrap/less/layouts.less";
+@import "../../../../assets/bootstrap/less/scaffolding.less";
+@import "../../../../assets/bootstrap/less/grid.less";
+@import "../../../../assets/bootstrap/less/layouts.less";
 
 // Base CSS
-@import "../../../assets/bootstrap/less/type.less";
-@import "../../../assets/bootstrap/less/code.less";
-@import "../../../assets/bootstrap/less/forms.less";
-@import "../../../assets/bootstrap/less/tables.less";
+@import "../../../../assets/bootstrap/less/type.less";
+@import "../../../../assets/bootstrap/less/code.less";
+@import "../../../../assets/bootstrap/less/forms.less";
+@import "../../../../assets/bootstrap/less/tables.less";
 
 // Components: common
-@import "../../../assets/bootstrap/less/sprites.less";
-@import "../../../assets/bootstrap/less/dropdowns.less";
-@import "../../../assets/bootstrap/less/wells.less";
-@import "../../../assets/bootstrap/less/component-animations.less";
-@import "../../../assets/bootstrap/less/close.less";
+@import "../../../../assets/bootstrap/less/sprites.less";
+@import "../../../../assets/bootstrap/less/dropdowns.less";
+@import "../../../../assets/bootstrap/less/wells.less";
+@import "../../../../assets/bootstrap/less/component-animations.less";
+@import "../../../../assets/bootstrap/less/close.less";
 
 // Components: Buttons & Alerts
-@import "../../../assets/bootstrap/less/buttons.less";
-@import "../../../assets/bootstrap/less/button-groups.less";
-@import "../../../assets/bootstrap/less/alerts.less"; // Note: alerts share common CSS with buttons and thus have styles in buttons.less
+@import "../../../../assets/bootstrap/less/buttons.less";
+@import "../../../../assets/bootstrap/less/button-groups.less";
+@import "../../../../assets/bootstrap/less/alerts.less"; // Note: alerts share common CSS with buttons and thus have styles in buttons.less
 
 // Components: Nav
-@import "../../../assets/bootstrap/less/navs.less";
-@import "../../../assets/bootstrap/less/navbar.less";
-@import "../../../assets/bootstrap/less/breadcrumbs.less";
-@import "../../../assets/bootstrap/less/pagination.less";
-@import "../../../assets/bootstrap/less/pager.less";
+@import "../../../../assets/bootstrap/less/navs.less";
+@import "../../../../assets/bootstrap/less/navbar.less";
+@import "../../../../assets/bootstrap/less/breadcrumbs.less";
+@import "../../../../assets/bootstrap/less/pagination.less";
+@import "../../../../assets/bootstrap/less/pager.less";
 
 // Components: Popovers
-@import "../../../assets/bootstrap/less/modals.less";
-@import "../../../assets/bootstrap/less/tooltip.less";
-@import "../../../assets/bootstrap/less/popovers.less";
+@import "../../../../assets/bootstrap/less/modals.less";
+@import "../../../../assets/bootstrap/less/tooltip.less";
+@import "../../../../assets/bootstrap/less/popovers.less";
 
 // Components: Misc
-@import "../../../assets/bootstrap/less/thumbnails.less";
-@import "../../../assets/bootstrap/less/media.less";
-@import "../../../assets/bootstrap/less/labels-badges.less";
-@import "../../../assets/bootstrap/less/progress-bars.less";
-@import "../../../assets/bootstrap/less/accordion.less";
-@import "../../../assets/bootstrap/less/carousel.less";
-@import "../../../assets/bootstrap/less/hero-unit.less";
+@import "../../../../assets/bootstrap/less/thumbnails.less";
+@import "../../../../assets/bootstrap/less/media.less";
+@import "../../../../assets/bootstrap/less/labels-badges.less";
+@import "../../../../assets/bootstrap/less/progress-bars.less";
+@import "../../../../assets/bootstrap/less/accordion.less";
+@import "../../../../assets/bootstrap/less/carousel.less";
+@import "../../../../assets/bootstrap/less/hero-unit.less";
 
 // Utility classes
-@import "../../../assets/bootstrap/less/utilities.less"; // Has to be last to override when necessary
+@import "../../../../assets/bootstrap/less/utilities.less"; // Has to be last to override when necessary
 
 // Responsive
-@import "../../../assets/bootstrap/less/responsive.less";
+@import "../../../../assets/bootstrap/less/responsive.less";
 
 @import "variables.less";
 @import "../../../../plugins/login.less";