diff --git a/examples/getstarted/api/country/models/Country.settings.json b/examples/getstarted/api/country/models/Country.settings.json
index fd54aa3efd..229a51aa23 100755
--- a/examples/getstarted/api/country/models/Country.settings.json
+++ b/examples/getstarted/api/country/models/Country.settings.json
@@ -5,23 +5,39 @@
     "displayName": "Country",
     "singularName": "country",
     "pluralName": "countries",
-    "description": ""
+    "description": "",
+    "name": "Country"
   },
   "options": {
     "draftAndPublish": false,
     "comment": ""
   },
+  "pluginOptions": {
+    "i18n": {
+      "localized": true
+    }
+  },
   "attributes": {
     "name": {
       "type": "string",
       "required": true,
-      "minLength": 3
+      "minLength": 3,
+      "pluginOptions": {
+        "i18n": {
+          "localized": true
+        }
+      }
     },
     "code": {
       "type": "string",
       "maxLength": 3,
       "unique": true,
-      "minLength": 2
+      "minLength": 2,
+      "pluginOptions": {
+        "i18n": {
+          "localized": true
+        }
+      }
     }
   }
 }
diff --git a/examples/getstarted/config/functions/register.js b/examples/getstarted/config/functions/register.js
new file mode 100644
index 0000000000..81a7f05c45
--- /dev/null
+++ b/examples/getstarted/config/functions/register.js
@@ -0,0 +1,10 @@
+'use strict';
+
+/**
+ * An asynchronous register function that runs before
+ * your application is loaded.
+ *
+ * This gives you an opportunity to extend code.
+ */
+
+module.exports = () => {};
diff --git a/packages/core/strapi/lib/Strapi.js b/packages/core/strapi/lib/Strapi.js
index 92968913b1..bd5d5b0f33 100644
--- a/packages/core/strapi/lib/Strapi.js
+++ b/packages/core/strapi/lib/Strapi.js
@@ -165,7 +165,7 @@ class Strapi {
 
   async openAdmin({ isInitialized }) {
     const shouldOpenAdmin =
-      this.config.environment === 'development' &&
+      this.config.get('environment') === 'development' &&
       this.config.get('server.admin.autoOpen', true) !== false;
 
     if (shouldOpenAdmin || !isInitialized) {
@@ -302,7 +302,7 @@ class Strapi {
     await this.db.schema.sync();
 
     this.store = createCoreStore({
-      environment: this.config.environment,
+      environment: this.config.get('environment'),
       db: this.db,
     });
 
diff --git a/packages/core/strapi/lib/core/bootstrap.js b/packages/core/strapi/lib/core/bootstrap.js
index 60807c5e9f..18210109fd 100644
--- a/packages/core/strapi/lib/core/bootstrap.js
+++ b/packages/core/strapi/lib/core/bootstrap.js
@@ -33,9 +33,10 @@ module.exports = function(strapi) {
   const allApisSchemas = Object.values(strapi.api).flatMap(api => Object.values(api.models));
   validateContentTypesUnicity(allApisSchemas);
 
-  // set default services and default controllers
+  // add user's content-types, controller and services
   for (const apiName in strapi.api) {
     const api = strapi.api[apiName];
+    _.defaultsDeep(api, { config: { routes: [] } }); // TODO: remove V4
     for (const modelName in api.models) {
       const model = api.models[modelName];
       model.info.displayName = model.info.displayName || model.info.name;
@@ -45,31 +46,18 @@ module.exports = function(strapi) {
       strapi.container.get('content-types').add(`api::${apiName}`, {
         [modelName]: { schema: model, actions: model.actions, lifecycles: model.lifecycles },
       });
-
       const contentType = strapi.contentType(`api::${apiName}.${modelName}`);
 
       const { service, controller } = createCoreApi({ model: contentType, api, strapi });
+      // TODO: remove V4
       _.set(strapi.api[apiName], ['services', modelName], service);
       _.set(strapi.api[apiName], ['controllers', modelName], controller);
+
+      strapi.container.get('controllers').add(`api::${apiName}`, { [modelName]: controller });
+      strapi.container.get('services').add(`api::${apiName}`, { [modelName]: service });
     }
   }
 
-  // Set user's controllers.
-  strapi.controllers = Object.keys(strapi.api || []).reduce((acc, apiName) => {
-    strapi.container.get('controllers').add(`api::${apiName}`, strapi.api[apiName].controllers);
-    for (let controllerName in strapi.api[apiName].controllers) {
-      let controller = strapi.api[apiName].controllers[controllerName];
-      acc[controllerName] = controller;
-    }
-
-    return acc;
-  }, {});
-
-  // Set routes.
-  strapi.config.routes = Object.keys(strapi.api || []).reduce((acc, key) => {
-    return acc.concat(_.get(strapi.api[key], 'config.routes') || {});
-  }, []);
-
   // TODO: delete v3 code
   _.forEach(strapi.plugins, plugin => {
     _.forEach(plugin.middlewares, (middleware, middlewareUID) => {
diff --git a/packages/core/strapi/lib/core/domain/module/index.js b/packages/core/strapi/lib/core/domain/module/index.js
index 9633c468f5..8a3f6560ee 100644
--- a/packages/core/strapi/lib/core/domain/module/index.js
+++ b/packages/core/strapi/lib/core/domain/module/index.js
@@ -2,6 +2,8 @@
 
 const { validateModule } = require('./validation');
 
+const uidToPath = uid => uid.replace('::', '.');
+
 const createModule = (namespace, rawModule, strapi) => {
   try {
     validateModule(rawModule);
@@ -38,9 +40,12 @@ const createModule = (namespace, rawModule, strapi) => {
       strapi.container.get('policies').add(namespace, rawModule.policies);
       strapi.container.get('middlewares').add(namespace, rawModule.middlewares);
       strapi.container.get('controllers').add(namespace, rawModule.controllers);
-      strapi.container.get('config').set(namespace.replace('::', '.'), rawModule.config);
+      strapi.container.get('config').set(uidToPath(namespace), rawModule.config);
     },
     routes: rawModule.routes, // TODO: to remove v3
+    config(path) {
+      return strapi.container.get('config').get(`${uidToPath(namespace)}.${path}`);
+    },
     contentType(ctName) {
       return strapi.container.get('content-types').get(`${namespace}.${ctName}`);
     },
diff --git a/packages/core/strapi/lib/core/registries/controllers.js b/packages/core/strapi/lib/core/registries/controllers.js
index 09ef3b14cc..223c940484 100644
--- a/packages/core/strapi/lib/core/registries/controllers.js
+++ b/packages/core/strapi/lib/core/registries/controllers.js
@@ -3,7 +3,7 @@
 const { pickBy, has } = require('lodash/fp');
 const { addNamespace } = require('../utils');
 
-const policiesRegistry = () => {
+const controllersRegistry = () => {
   const controllers = {};
 
   return {
@@ -24,7 +24,15 @@ const policiesRegistry = () => {
         controllers[uid] = controller;
       }
     },
+    extend(controllerUID, extendFn) {
+      const currentController = this.get(controllerUID);
+      if (!currentController) {
+        throw new Error(`Controller ${controllerUID} doesn't exist`);
+      }
+      const newController = extendFn(currentController);
+      controllers[controllerUID] = newController;
+    },
   };
 };
 
-module.exports = policiesRegistry;
+module.exports = controllersRegistry;
diff --git a/packages/core/strapi/lib/core/registries/services.js b/packages/core/strapi/lib/core/registries/services.js
index 6bc47010db..8e3b480646 100644
--- a/packages/core/strapi/lib/core/registries/services.js
+++ b/packages/core/strapi/lib/core/registries/services.js
@@ -4,7 +4,7 @@ const _ = require('lodash');
 const { pickBy, has } = require('lodash/fp');
 const { addNamespace } = require('../utils');
 
-const contentTypesRegistry = strapi => {
+const servicesRegistry = strapi => {
   const services = {};
   const instanciatedServices = {};
 
@@ -42,4 +42,4 @@ const contentTypesRegistry = strapi => {
   };
 };
 
-module.exports = contentTypesRegistry;
+module.exports = servicesRegistry;
diff --git a/packages/core/strapi/lib/middlewares/router/index.js b/packages/core/strapi/lib/middlewares/router/index.js
index e77ca4f9e4..20e82b7d51 100644
--- a/packages/core/strapi/lib/middlewares/router/index.js
+++ b/packages/core/strapi/lib/middlewares/router/index.js
@@ -6,6 +6,7 @@
 
 // Public node modules.
 const _ = require('lodash');
+const { getOr } = require('lodash/fp');
 const Router = require('koa-router');
 const createEndpointComposer = require('./utils/composeEndpoint');
 
@@ -16,7 +17,7 @@ module.exports = strapi => {
     const router = new Router({ prefix: '/admin' });
 
     for (const route of strapi.admin.routes) {
-      composeEndpoint(route, { plugin: 'admin', router });
+      composeEndpoint(route, { pluginName: 'admin', router });
     }
 
     strapi.app.use(router.routes()).use(router.allowedMethods());
@@ -31,7 +32,7 @@ module.exports = strapi => {
       for (const route of plugin.routes || []) {
         const hasPrefix = _.has(route.config, 'prefix');
         composeEndpoint(route, {
-          plugin: pluginName,
+          pluginName,
           router: hasPrefix ? strapi.router : router,
         });
       }
@@ -41,15 +42,19 @@ module.exports = strapi => {
   };
 
   const registerAPIRoutes = () => {
-    strapi.router.prefix(strapi.config.get('middleware.settings.router.prefix', ''));
+    for (const apiName in strapi.api) {
+      const api = strapi.api[apiName];
+      const routes = getOr([], 'config.routes', api);
 
-    for (const route of strapi.config.routes) {
-      composeEndpoint(route, { router: strapi.router });
+      for (const route of routes) {
+        composeEndpoint(route, { apiName, router: strapi.router });
+      }
     }
   };
 
   return {
     initialize() {
+      strapi.router.prefix(strapi.config.get('middleware.settings.router.prefix', ''));
       registerAPIRoutes();
       registerAdminRoutes();
       registerPluginRoutes();
diff --git a/packages/core/strapi/lib/middlewares/router/utils/composeEndpoint.js b/packages/core/strapi/lib/middlewares/router/utils/composeEndpoint.js
index 29ddb83e22..ecf55001b3 100644
--- a/packages/core/strapi/lib/middlewares/router/utils/composeEndpoint.js
+++ b/packages/core/strapi/lib/middlewares/router/utils/composeEndpoint.js
@@ -2,7 +2,7 @@
 
 const _ = require('lodash');
 const compose = require('koa-compose');
-const { yup } = require('@strapi/utils');
+const { yup, policy: policyUtils } = require('@strapi/utils');
 
 const policyOrMiddlewareSchema = yup.lazy(value => {
   if (typeof value === 'string') {
@@ -62,19 +62,19 @@ const validateRouteConfig = routeConfig => {
   }
 };
 
-// Strapi utilities.
-const { finder, policy: policyUtils } = require('@strapi/utils');
-
 module.exports = strapi => {
   const routerChecker = createRouteChecker(strapi);
 
-  return (routeConfig, { plugin, router }) => {
+  return (routeConfig, { pluginName, router, apiName }) => {
     validateRouteConfig(routeConfig);
 
     try {
       const middlewares = resolveMiddlewares(routeConfig);
 
-      const { method, endpoint, policies, action } = routerChecker(routeConfig, plugin);
+      const { method, endpoint, policies, action } = routerChecker(routeConfig, {
+        pluginName,
+        apiName,
+      });
 
       if (_.isUndefined(action) || !_.isFunction(action)) {
         return strapi.log.warn(
@@ -113,7 +113,7 @@ const getMethod = route => _.trim(_.toLower(route.method));
 const getEndpoint = route => _.trim(route.path);
 
 const createRouteChecker = strapi => {
-  return (value, plugin) => {
+  return (value, { pluginName, apiName }) => {
     const method = getMethod(value);
     const endpoint = getEndpoint(value);
 
@@ -123,16 +123,15 @@ const createRouteChecker = strapi => {
 
     let controller;
 
-    if (plugin) {
-      if (plugin === 'admin') {
+    if (pluginName) {
+      if (pluginName === 'admin') {
         controller = strapi.admin.controllers[controllerKey];
       } else {
-        controller = strapi.plugin(plugin).controller(controllerKey);
+        controller = strapi.plugin(pluginName).controller(controllerKey);
       }
     } else {
-      controller = strapi.controllers[controllerKey];
+      controller = strapi.container.get('controllers').get(`api::${apiName}.${controllerKey}`);
     }
-
     if (!_.isFunction(controller[actionName])) {
       strapi.stopWithError(
         `Error creating endpoint ${method} ${endpoint}: handler not found "${controllerKey}.${actionName}"`
@@ -141,13 +140,6 @@ const createRouteChecker = strapi => {
 
     const action = controller[actionName].bind(controller);
 
-    // Retrieve the API's name where the controller is located
-    // to access to the right validators
-    const currentApiName = finder(
-      strapi.plugin(plugin) || strapi.api || strapi.admin,
-      controllerKey
-    );
-
     const { bodyPolicy } = policyUtils;
 
     const globalPolicy = policyUtils.globalPolicy({
@@ -155,13 +147,13 @@ const createRouteChecker = strapi => {
       action: actionName,
       method,
       endpoint,
-      plugin,
+      plugin: pluginName,
     });
 
     const policyOption = _.get(value, 'config.policies', []);
 
     const routePolicies = policyOption.map(policyConfig => {
-      return policyUtils.get(policyConfig, plugin, currentApiName);
+      return policyUtils.get(policyConfig, { pluginName, apiName });
     });
 
     // Init policies array.
diff --git a/packages/core/utils/lib/finder.js b/packages/core/utils/lib/finder.js
deleted file mode 100644
index bb005cdf23..0000000000
--- a/packages/core/utils/lib/finder.js
+++ /dev/null
@@ -1,29 +0,0 @@
-'use strict';
-
-/**
- * Module dependencies
- */
-
-const _ = require('lodash');
-
-/**
- * Find controller's location
- */
-
-module.exports = (api, controller) => {
-  if (!_.isObject(api)) {
-    throw new Error('Should be an object');
-  }
-  if (_.isString(controller)) {
-    controller = controller.toLowerCase();
-  } else {
-    throw new Error('Should be an object or a string');
-  }
-
-  const where = _.findKey(api, o => {
-    return _.get(o, `controllers.${controller}`);
-  });
-
-  // Return the API's name where the controller is located
-  return where;
-};
diff --git a/packages/core/utils/lib/index.js b/packages/core/utils/lib/index.js
index d6d38554bd..0eaeb93576 100644
--- a/packages/core/utils/lib/index.js
+++ b/packages/core/utils/lib/index.js
@@ -12,7 +12,6 @@ const {
 const parseMultipartData = require('./parse-multipart');
 const sanitizeEntity = require('./sanitize-entity');
 const parseType = require('./parse-type');
-const finder = require('./finder');
 const policy = require('./policy');
 const templateConfiguration = require('./template-configuration');
 const { yup, formatYupErrors } = require('./validators');
@@ -40,7 +39,6 @@ const providerFactory = require('./provider-factory');
 module.exports = {
   yup,
   formatYupErrors,
-  finder,
   policy,
   templateConfiguration,
   convertRestQueryParams,
diff --git a/packages/core/utils/lib/policy.js b/packages/core/utils/lib/policy.js
index 37e19ec65b..615c09399f 100644
--- a/packages/core/utils/lib/policy.js
+++ b/packages/core/utils/lib/policy.js
@@ -38,7 +38,7 @@ const resolvePolicy = policyName => {
   return resolver ? resolveHandler(resolver.get)(policyName) : undefined;
 };
 
-const searchLocalPolicy = (policy, plugin, apiName) => {
+const searchLocalPolicy = (policy, { pluginName, apiName }) => {
   let [absoluteApiName, policyName] = policy.split('.');
   let absoluteApi = _.get(strapi.api, absoluteApiName);
   const resolver = policyResolvers.find(({ name }) => name === 'plugin');
@@ -47,9 +47,9 @@ const searchLocalPolicy = (policy, plugin, apiName) => {
     return resolveHandler(getPolicyIn(absoluteApi, policyName));
   }
 
-  const pluginPolicy = `${PLUGIN_PREFIX}${plugin}.${policy}`;
+  const pluginPolicy = `${PLUGIN_PREFIX}${pluginName}.${policy}`;
 
-  if (plugin && resolver.exists(pluginPolicy)) {
+  if (pluginName && resolver.exists(pluginPolicy)) {
     return resolveHandler(resolver.get(pluginPolicy));
   }
 
@@ -137,7 +137,7 @@ const policyResolvers = [
   },
 ];
 
-const get = (policy, plugin, apiName) => {
+const get = (policy, { pluginName, apiName }) => {
   if (typeof policy === 'function') {
     return policy;
   }
@@ -150,7 +150,7 @@ const get = (policy, plugin, apiName) => {
     return _.isPlainObject(policy) ? resolvedPolicy(args) : resolvedPolicy;
   }
 
-  const localPolicy = searchLocalPolicy(policy, plugin, apiName);
+  const localPolicy = searchLocalPolicy(policy, { pluginName, apiName });
 
   if (localPolicy !== undefined) {
     return localPolicy;
diff --git a/packages/plugins/i18n/server/services/core-api.js b/packages/plugins/i18n/server/services/core-api.js
index 7acfa86f63..b618fd0580 100644
--- a/packages/plugins/i18n/server/services/core-api.js
+++ b/packages/plugins/i18n/server/services/core-api.js
@@ -199,21 +199,12 @@ const addCreateLocalizationAction = contentType => {
 
   const localizationRoute = createLocalizationRoute(contentType);
 
-  strapi.config.routes.push(localizationRoute);
+  strapi.api[apiName].config.routes.push(localizationRoute);
 
-  // TODO: to replace with:
-  // strapi.controllers.extends(`api::${apiName}.${modelName}`, (contr) => ({
-  //   ...controller,
-  //   createLocalization = createLocalizationHandler(contentType),
-  // }));
-  // OR
-  // strapi.api(apiName).controllers.extends(modelName, (contr) => ({
-  //   ...controller,
-  //   createLocalization = createLocalizationHandler(contentType),
-  // }));
-
-  const controller = strapi.container.get('controllers').get(`api::${apiName}.${modelName}`);
-  controller.createLocalization = createLocalizationHandler(contentType);
+  strapi.container.get('controllers').extend(`api::${apiName}.${modelName}`, controller => ({
+    ...controller,
+    createLocalization: createLocalizationHandler(contentType),
+  }));
 };
 
 const mergeCustomizer = (dest, src) => {
diff --git a/packages/plugins/users-permissions/server/middlewares/users-permissions.js b/packages/plugins/users-permissions/server/middlewares/users-permissions.js
index e43b173bc3..aaf5e4ddcc 100644
--- a/packages/plugins/users-permissions/server/middlewares/users-permissions.js
+++ b/packages/plugins/users-permissions/server/middlewares/users-permissions.js
@@ -1,6 +1,7 @@
 'use strict';
 
 const _ = require('lodash');
+const { getOr } = require('lodash/fp');
 
 module.exports = {
   defaults: { 'users-permissions': { enabled: true } },
@@ -16,10 +17,13 @@ module.exports = {
         }
       });
 
-      _.forEach(strapi.config.routes, value => {
-        if (_.get(value.config, 'policies')) {
-          value.config.policies.unshift('plugin::users-permissions.permissions');
-        }
+      _.forEach(strapi.api, api => {
+        const routes = getOr([], 'config.routes', api);
+        _.forEach(routes, route => {
+          if (_.get(route.config, 'policies')) {
+            route.config.policies.unshift('plugin::users-permissions.permissions');
+          }
+        });
       });
 
       if (strapi.plugins) {