diff --git a/addons/bus/static/src/js/services/bus_service.js b/addons/bus/static/src/js/services/bus_service.js
index 78be7a9740a..80247843dad 100644
--- a/addons/bus/static/src/js/services/bus_service.js
+++ b/addons/bus/static/src/js/services/bus_service.js
@@ -4,6 +4,7 @@ odoo.define('bus.BusService', function (require) {
 var bus = require('bus.bus').bus;
 
 var AbstractService = require('web.AbstractService');
+var core = require('web.core');
 
 var BusService =  AbstractService.extend({
     name: 'bus_service',
@@ -91,6 +92,8 @@ var BusService =  AbstractService.extend({
 
 });
 
+core.serviceRegistry.add('bus_service', BusService);
+
 return BusService;
 
 });
diff --git a/addons/mail/static/src/js/services/chat_manager.js b/addons/mail/static/src/js/services/chat_manager.js
index b7c46f2d4c1..421a9053134 100644
--- a/addons/mail/static/src/js/services/chat_manager.js
+++ b/addons/mail/static/src/js/services/chat_manager.js
@@ -1746,6 +1746,8 @@ var ChatManager =  AbstractService.extend({
 
 });
 
+core.serviceRegistry.add('chat_manager', ChatManager);
+
 return ChatManager;
 
 });
diff --git a/addons/mail/static/src/js/services/chat_window_manager.js b/addons/mail/static/src/js/services/chat_window_manager.js
index f82da369ecf..be8588f9cb1 100644
--- a/addons/mail/static/src/js/services/chat_window_manager.js
+++ b/addons/mail/static/src/js/services/chat_window_manager.js
@@ -527,6 +527,8 @@ var ChatWindowManager =  AbstractService.extend({
 
 });
 
+core.serviceRegistry.add('chat_window_manager', ChatWindowManager);
+
 return ChatWindowManager;
 
 });
diff --git a/addons/web/static/src/js/core/abstract_service.js b/addons/web/static/src/js/core/abstract_service.js
index cbd6c1322ca..14efef09b39 100644
--- a/addons/web/static/src/js/core/abstract_service.js
+++ b/addons/web/static/src/js/core/abstract_service.js
@@ -6,7 +6,6 @@ var Mixins = require('web.mixins');
 var ServicesMixin = require('web.ServicesMixin');
 
 var AbstractService = Class.extend(Mixins.EventDispatcherMixin, ServicesMixin, {
-    Services: [],
     dependencies: [],
     name: null,
     init: function (parent) {
@@ -15,13 +14,5 @@ var AbstractService = Class.extend(Mixins.EventDispatcherMixin, ServicesMixin, {
     },
 });
 
-var realExtend = AbstractService.extend;
-
-AbstractService.extend = function () {
-    var Service = realExtend.apply(this, arguments);
-    AbstractService.prototype.Services.push(Service);
-    return Service;
-};
-
 return AbstractService;
 });
diff --git a/addons/web/static/src/js/core/registry.js b/addons/web/static/src/js/core/registry.js
index d70c09e4ae0..f925b0ea30a 100644
--- a/addons/web/static/src/js/core/registry.js
+++ b/addons/web/static/src/js/core/registry.js
@@ -25,6 +25,7 @@ var Registry = Class.extend({
      */
     init: function (mapping) {
         this.map = Object.create(mapping || null);
+        this.listeners = []; // listening callbacks on newly added items.
     },
 
     //--------------------------------------------------------------------------
@@ -34,12 +35,17 @@ var Registry = Class.extend({
     /**
      * Add a key (and a value) to the registry.
      *
+     * Notify the listeners on newly added item in the registry.
+     *
      * @param {string} key
      * @param {any} value
      * @returns {Registry} can be used to chain add calls.
      */
     add: function (key, value) {
         this.map[key] = value;
+        _.each(this.listeners, function (callback) {
+            callback(key, value);
+        });
         return this;
     },
     /**
@@ -89,6 +95,14 @@ var Registry = Class.extend({
         }
         return null;
     },
+    /**
+     * Register a callback to execute when items are added to the registry.
+     *
+     * @param {function} callback function with parameters (key, value).
+     */
+    onAdd: function (callback) {
+        this.listeners.push(callback);
+    },
 });
 
 return Registry;
diff --git a/addons/web/static/src/js/core/service_mixins.js b/addons/web/static/src/js/core/service_mixins.js
index d5abf727704..052e2a6a3d9 100644
--- a/addons/web/static/src/js/core/service_mixins.js
+++ b/addons/web/static/src/js/core/service_mixins.js
@@ -1,58 +1,86 @@
 odoo.define('web.ServiceProviderMixin', function (require) {
 "use strict";
 
-var AbstractService = require('web.AbstractService');
-var utils = require('web.utils');
+var core = require('web.core');
 
 var ServiceProviderMixin = {
-    services: {},
-    init: function () {
+    services: {}, // dict containing deployed service instances
+    UndeployedServices: {}, // dict containing classes of undeployed services
+    /**
+     * @override
+     */
+    init: function (parent) {
+        var self = this;
         // to properly instantiate services with this as parent, this mixin
         // assumes that it is used along the EventDispatcherMixin, and that
         // EventDispatchedMixin's init is called first
-        var self = this;
-        // as EventDispatcherMixin's init is already called, this handler has to
-        // be bound manually
+        // as EventDispatcherMixin's init is already called, this handler has
+        // to be bound manually
         this.on('call_service', this, this._call_service.bind(this));
 
-        var sortedServices = this._sortServices(AbstractService.prototype.Services);
-        _.each(sortedServices, function (Service) {
-            var service = new Service(self);
-            self.services[service.name] = service;
+        // add already registered services from the service registry
+        _.each(core.serviceRegistry.map, function (Service, serviceName) {
+            self.UndeployedServices[serviceName] = Service;
+        });
+        this._deployServices();
+
+        // listen on newly added services
+        core.serviceRegistry.onAdd(function (serviceName, Service) {
+            self.UndeployedServices[serviceName] = Service;
+            self._deployServices();
         });
     },
+
+    //--------------------------------------------------------------------------
+    // Private
+    //--------------------------------------------------------------------------
+
+    /**
+     * @private
+     */
+    _deployServices: function () {
+        var self = this;
+        var done = false;
+        while (!done) {
+            var Service = _.find(this.UndeployedServices, function (Service) {
+                // no missing dependency
+                return !_.some(Service.prototype.dependencies, function (depName) {
+                    return !self.services[depName];
+                });
+            });
+            if (Service) {
+                this.services[Service.prototype.name] = new Service(this);
+                delete this.UndeployedServices[Service.prototype.name];
+            } else {
+                done = true;
+            }
+        }
+    },
+
+    //--------------------------------------------------------------------------
+    // Handlers
+    //--------------------------------------------------------------------------
+
+    /**
+     * Call the 'service', using data from the 'event' that
+     * has triggered the service call.
+     *
+     * For the ajax service, the arguments are extended with
+     * the target so that it can call back the caller.
+     *
+     * @private
+     * @param  {OdooEvent} event
+     */
     _call_service: function (event) {
-        var service = this.services[event.data.service];
         var args = event.data.args || [];
-        // ajax service uses an extra 'target' argument for rpc
         if (event.data.service === 'ajax' && event.data.method === 'rpc') {
+            // ajax service uses an extra 'target' argument for rpc
             args = args.concat(event.target);
         }
+        var service = this.services[event.data.service];
         var result = service[event.data.method].apply(service, args);
         event.data.callback(result);
     },
-    _sortServices: function (services) {
-        var nodes = {};
-        // Create nodes (services)
-        _.each(services, function (Service) {
-            nodes[Service.prototype.name] = Service.prototype.dependencies;
-        });
-        var sorted;
-        try {
-            sorted = utils.topologicalSort(nodes);
-        } catch (err) {
-            console.warn('topologicalSort Error:', err.message);
-            sorted = nodes;
-        }
-        // Sort services based on sorted
-        // Note: we convert sorted to an object key=>index for efficiency
-        var sortedObj = _.invert(_.object(_.pairs(sorted)));
-        sorted = _.sortBy(services, function (Service) {
-            return sortedObj[Service.prototype.name];
-        });
-
-        return sorted;
-    },
 };
 
 return ServiceProviderMixin;
diff --git a/addons/web/static/src/js/core/utils.js b/addons/web/static/src/js/core/utils.js
index 0b4af722203..1bdd9e70a69 100644
--- a/addons/web/static/src/js/core/utils.js
+++ b/addons/web/static/src/js/core/utils.js
@@ -300,37 +300,6 @@ var utils = {
         }
         return fn(mod, Math.floor(x));
     },
-    /**
-     * Topological sort of nodes
-     *
-     * @param {Object} nodes where key is name of node, and value is list of
-     *                       names of dependent nodes.
-     * @param {string[]} nodes[name] list of named dependencies of node having
-     *                       'name' as its name.
-     * @return {string[]} topological sort of nodes by their names.
-     * @throws {Error} if there is at least one circular
-     *                       dependency between nodes
-     */
-    topologicalSort: function (nodes) {
-        var sorted = [];
-        var unresolved = nodes;
-        while (!_.isEmpty(unresolved)) {
-            // Get all nodes that have no dependency
-            var resolvable = _.pick(unresolved, function (dependencies, name) {
-                return _.isEmpty(_.difference(dependencies, sorted));
-            });
-            if (_.isEmpty(resolvable)) {
-                throw new Error("Circular dependency detected");
-            }
-            // Append them to sorted
-            sorted = _.union(sorted, _.keys(resolvable));
-            // Remove these nodes from unresolved
-            _.each(resolvable, function (dependencies, name) {
-                unresolved = _.omit(unresolved, name);
-            });
-        }
-        return sorted;
-    },
     /**
      * performs a half up rounding with a fixed amount of decimals, correcting for float loss of precision
      * See the corresponding float_round() in server/tools/float_utils.py for more info
diff --git a/addons/web/static/src/js/services/ajax_service.js b/addons/web/static/src/js/services/ajax_service.js
index 480549347d4..3446f651a59 100644
--- a/addons/web/static/src/js/services/ajax_service.js
+++ b/addons/web/static/src/js/services/ajax_service.js
@@ -2,6 +2,7 @@ odoo.define('web.AjaxService', function (require) {
 "use strict";
 
 var AbstractService = require('web.AbstractService');
+var core = require('web.core');
 var session = require('web.session');
 
 var AjaxService = AbstractService.extend({
@@ -21,6 +22,8 @@ var AjaxService = AbstractService.extend({
     },
 });
 
+core.serviceRegistry.add('ajax', AjaxService);
+
 return AjaxService;
 
 });
diff --git a/addons/web/static/src/js/services/core.js b/addons/web/static/src/js/services/core.js
index 73071a2a65d..522d6b07302 100644
--- a/addons/web/static/src/js/services/core.js
+++ b/addons/web/static/src/js/services/core.js
@@ -41,6 +41,7 @@ return {
     crash_registry: new Registry(),
     search_filters_registry: new Registry(),
     search_widgets_registry: new Registry(),
+    serviceRegistry: new Registry(),
     /**
      * @type {String}
      */
diff --git a/addons/web/static/src/js/services/local_storage_service.js b/addons/web/static/src/js/services/local_storage_service.js
index a4527026238..7a8c803a0f9 100644
--- a/addons/web/static/src/js/services/local_storage_service.js
+++ b/addons/web/static/src/js/services/local_storage_service.js
@@ -2,6 +2,7 @@ odoo.define('web.LocalStorageService', function (require) {
 'use strict';
 
 var AbstractService = require('web.AbstractService');
+var core = require('web.core');
 var localStorage = require('web.local_storage');
 
 var LocalStorageService = AbstractService.extend({
@@ -20,6 +21,8 @@ var LocalStorageService = AbstractService.extend({
     }
 });
 
+core.serviceRegistry.add('local_storage', LocalStorageService);
+
 return LocalStorageService;
 
 });
diff --git a/addons/web/static/src/js/services/report_service.js b/addons/web/static/src/js/services/report_service.js
index a2bb8759a24..cfd62c0499f 100644
--- a/addons/web/static/src/js/services/report_service.js
+++ b/addons/web/static/src/js/services/report_service.js
@@ -6,6 +6,7 @@ odoo.define('web.ReportService', function (require) {
  */
 
 var AbstractService = require('web.AbstractService');
+var core = require('web.core');
 
 var ReportService = AbstractService.extend({
     name: 'report',
@@ -28,6 +29,8 @@ var ReportService = AbstractService.extend({
     },
 });
 
+core.serviceRegistry.add('report', ReportService);
+
 return ReportService;
 
 });
diff --git a/addons/web/static/tests/helpers/test_utils.js b/addons/web/static/tests/helpers/test_utils.js
index 6b2c09d2631..7070716ed27 100644
--- a/addons/web/static/tests/helpers/test_utils.js
+++ b/addons/web/static/tests/helpers/test_utils.js
@@ -19,7 +19,6 @@ var core = require('web.core');
 var dom = require('web.dom');
 var session = require('web.session');
 var MockServer = require('web.MockServer');
-var utils = require('web.utils');
 var Widget = require('web.Widget');
 
 var DebouncedField = basic_fields.DebouncedField;
@@ -405,7 +404,7 @@ function addMockEnvironment(widget, params) {
     // Dispatch service calls
     // Note: some services could call other services at init,
     // Which is why we have to init services after that
-    var services = {};
+    var services = {ajax: null}; // mocked ajax service already loaded
     intercept(widget, 'call_service', function (ev) {
         var args, result;
         if (ev.data.service === 'ajax') {
@@ -420,36 +419,22 @@ function addMockEnvironment(widget, params) {
         }
         ev.data.callback(result);
     });
-    // Instantiate services
-    // Note: ensure topological sort of services based on their dependencies
-    var sortServices = function (services) {
-        // Create nodes (services), with ajax already loaded
-        var nodes = { ajax: [] };
-        _.each(services, function (Service) {
-            nodes[Service.prototype.name] = Service.prototype.dependencies;
+
+    // Deploy services
+    var done = false;
+    while (!done) {
+        var index = _.findIndex(params.services, function (Service) {
+            return !_.some(Service.prototype.dependencies, function (depName) {
+                return !_.has(services, depName);
+            });
         });
-        var sorted;
-        try {
-            sorted = utils.topologicalSort(nodes);
-        } catch (err) {
-            console.warn('topologicalSort Error:', err.message);
-            sorted = nodes;
+        if (index !== -1) {
+            var Service = params.services.splice(index, 1)[0];
+            services[Service.prototype.name] = new Service(widget);
+        } else {
+            done = true;
         }
-        // Remove ajax from sorted
-        sorted = _.without(sorted, 'ajax');
-        // Sort services based on sorted
-        // Note: we convert sorted to an object key=>index for efficiency
-        var sortedObj = _.invert(_.object(_.pairs(sorted)));
-        sorted = _.sortBy(services, function (Service) {
-            return sortedObj[Service.prototype.name];
-        });
-        return sorted;
-    };
-    var sortedServices = sortServices(params.services);
-    _.each(sortedServices, function (Service) {
-        var service = new Service(widget);
-        services[service.name] = service;
-    });
+    }
 
     intercept(widget, 'load_action', function (event) {
         mockServer.performRpc('/web/action/load', {