diff --git a/src/addons/addons.module.ts b/src/addons/addons.module.ts
new file mode 100644
index 000000000..c73da06f0
--- /dev/null
+++ b/src/addons/addons.module.ts
@@ -0,0 +1,24 @@
+// (C) Copyright 2015 Moodle Pty Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { NgModule } from '@angular/core';
+
+import { AddonPrivateFilesInitModule } from './privatefiles/privatefiles-init.module';
+
+@NgModule({
+    imports: [
+        AddonPrivateFilesInitModule,
+    ],
+})
+export class AddonsModule {}
diff --git a/src/app/app.module.ts b/src/app/app.module.ts
index df93cf574..0206d2dde 100644
--- a/src/app/app.module.ts
+++ b/src/app/app.module.ts
@@ -12,65 +12,22 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import { NgModule, Injector } from '@angular/core';
+import { NgModule } from '@angular/core';
 import { BrowserModule } from '@angular/platform-browser';
 import { RouteReuseStrategy } from '@angular/router';
-import { HttpClient, HttpClientModule, HTTP_INTERCEPTORS } from '@angular/common/http';
-
-import { IonicModule, IonicRouteStrategy, Platform } from '@ionic/angular';
-
-import { AppComponent } from './app.component';
-import { AppRoutingModule } from './app-routing.module';
-import { CoreInterceptor } from '@classes/interceptor';
-
-// Import core services.
-import { CoreAppProvider } from '@services/app';
-import { CoreConfigProvider } from '@services/config';
-import { CoreCronDelegate } from '@services/cron';
-import { CoreDbProvider } from '@services/db';
-import { CoreFileHelperProvider } from '@services/file-helper';
-import { CoreFileSessionProvider } from '@services/file-session';
-import { CoreFileProvider, CoreFile } from '@services/file';
-import { CoreFilepoolProvider } from '@services/filepool';
-import { CoreGeolocationProvider } from '@services/geolocation';
-import { CoreGroupsProvider } from '@services/groups';
-import { CoreInitDelegate, CoreInit } from '@services/init';
-import { CoreLangProvider } from '@services/lang';
-import { CoreLocalNotificationsProvider } from '@services/local-notifications';
-import { CorePluginFileDelegate } from '@services/plugin-file.delegate';
-import { CoreSitesProvider, CoreSites } from '@services/sites';
-import { CoreSyncProvider } from '@services/sync';
-import { CoreUpdateManagerProvider, CoreUpdateManager } from '@services/update-manager';
-import { CoreWSProvider } from '@services/ws';
-import { CoreDomUtilsProvider } from '@services/utils/dom';
-import { CoreIframeUtilsProvider } from '@services/utils/iframe';
-import { CoreMimetypeUtilsProvider } from '@services/utils/mimetype';
-import { CoreTextUtilsProvider } from '@services/utils/text';
-import { CoreTimeUtilsProvider } from '@services/utils/time';
-import { CoreUrlUtilsProvider } from '@services/utils/url';
-import { CoreUtilsProvider } from '@services/utils/utils';
-
-// Import init DB functions of core services.
-import { initCoreFilepoolDB } from '@services/filepool.db';
-import { initCoreSitesDB } from '@services/sites.db';
-import { initCoreSyncDB } from '@services/sync.db';
-import { initCoreSearchHistoryDB } from '@features/search/services/search.history.db';
-
-// Import core modules.
-import { CoreEmulatorModule } from '@features/emulator/emulator.module';
-import { CoreLoginModule } from '@features/login/login.module';
-import { CoreCoursesModule } from '@features/courses/courses.module';
-import { CoreSettingsInitModule } from '@features/settings/settings-init.module';
-import { CoreFileUploaderInitModule } from '@features/fileuploader/fileuploader-init.module';
-
-// Import addons init modules.
-import { AddonPrivateFilesInitModule } from '@/addons/privatefiles/privatefiles-init.module';
-
-import { setSingletonsInjector } from '@singletons/core.singletons';
+import { HttpClient, HttpClientModule } from '@angular/common/http';
 
 import { TranslateModule, TranslateLoader } from '@ngx-translate/core';
 import { TranslateHttpLoader } from '@ngx-translate/http-loader';
 
+import { IonicModule, IonicRouteStrategy } from '@ionic/angular';
+
+import { CoreModule } from '@/core/core.module';
+import { AddonsModule } from '@/addons/addons.module';
+
+import { AppComponent } from './app.component';
+import { AppRoutingModule } from './app-routing.module';
+
 // For translate loader. AoT requires an exported function for factories.
 export function createTranslateLoader(http: HttpClient): TranslateHttpLoader {
     return new TranslateHttpLoader(http, './assets/lang/', '.json');
@@ -91,93 +48,12 @@ export function createTranslateLoader(http: HttpClient): TranslateHttpLoader {
             },
         }),
         AppRoutingModule,
-        CoreEmulatorModule,
-        CoreLoginModule,
-        CoreCoursesModule,
-        CoreSettingsInitModule,
-        CoreFileUploaderInitModule,
-        AddonPrivateFilesInitModule,
+        CoreModule,
+        AddonsModule,
     ],
     providers: [
         { provide: RouteReuseStrategy, useClass: IonicRouteStrategy },
-        { provide: HTTP_INTERCEPTORS, useClass: CoreInterceptor, multi: true },
-        CoreAppProvider,
-        CoreConfigProvider,
-        CoreCronDelegate,
-        CoreDbProvider,
-        CoreFileHelperProvider,
-        CoreFileSessionProvider,
-        CoreFileProvider,
-        CoreFilepoolProvider,
-        CoreGeolocationProvider,
-        CoreGroupsProvider,
-        CoreInitDelegate,
-        CoreLangProvider,
-        CoreLocalNotificationsProvider,
-        CorePluginFileDelegate,
-        CoreSitesProvider,
-        CoreSyncProvider,
-        CoreUpdateManagerProvider,
-        CoreWSProvider,
-        CoreDomUtilsProvider,
-        CoreIframeUtilsProvider,
-        CoreMimetypeUtilsProvider,
-        CoreTextUtilsProvider,
-        CoreTimeUtilsProvider,
-        CoreUrlUtilsProvider,
-        CoreUtilsProvider,
     ],
     bootstrap: [AppComponent],
 })
-export class AppModule {
-
-    constructor(injector: Injector, platform: Platform) {
-        // Set the injector.
-        setSingletonsInjector(injector);
-
-        this.initCoreServicesDB();
-
-        // Register a handler for platform ready.
-        CoreInit.instance.registerProcess({
-            name: 'CorePlatformReady',
-            priority: CoreInitDelegate.MAX_RECOMMENDED_PRIORITY + 400,
-            blocking: true,
-            load: async () => {
-                await platform.ready();
-            },
-        });
-
-        // Register the update manager as an init process.
-        CoreInit.instance.registerProcess(CoreUpdateManager.instance);
-
-        // Restore the user's session during the init process.
-        CoreInit.instance.registerProcess({
-            name: 'CoreRestoreSession',
-            priority: CoreInitDelegate.MAX_RECOMMENDED_PRIORITY + 200,
-            blocking: false,
-            load: CoreSites.instance.restoreSession.bind(CoreSites.instance),
-        });
-
-        // Register clear app tmp folder.
-        CoreInit.instance.registerProcess({
-            name: 'CoreClearTmpFolder',
-            priority: CoreInitDelegate.MAX_RECOMMENDED_PRIORITY + 150,
-            blocking: false,
-            load: CoreFile.instance.clearTmpFolder.bind(CoreFile.instance),
-        });
-
-        // Execute the init processes.
-        CoreInit.instance.executeInitProcesses();
-    }
-
-    /**
-     * Init the DB of core services.
-     */
-    protected initCoreServicesDB(): void {
-        initCoreFilepoolDB();
-        initCoreSitesDB();
-        initCoreSyncDB();
-        initCoreSearchHistoryDB();
-    }
-
-}
+export class AppModule {}
diff --git a/src/core/core.module.ts b/src/core/core.module.ts
new file mode 100644
index 000000000..839c48171
--- /dev/null
+++ b/src/core/core.module.ts
@@ -0,0 +1,87 @@
+// (C) Copyright 2015 Moodle Pty Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { HTTP_INTERCEPTORS } from '@angular/common/http';
+import { Injector, NgModule } from '@angular/core';
+
+import { Platform } from '@ionic/angular';
+
+import { CoreFeaturesModule } from './features/features.module';
+import { CoreFile } from './services/file';
+import { CoreInit, CoreInitDelegate } from './services/init';
+import { CoreInterceptor } from './classes/interceptor';
+import { CoreSites, CORE_SITE_SCHEMAS } from './services/sites';
+import { CoreUpdateManager } from './services/update-manager';
+import { setSingletonsInjector } from './singletons/core.singletons';
+import { SITE_SCHEMA as FILEPOOL_SITE_SCHEMA } from './services/filepool-db';
+import { SITE_SCHEMA as SITES_SITE_SCHEMA } from './services/sites-db';
+import { SITE_SCHEMA as SYNC_SITE_SCHEMA } from './services/sync-db';
+
+@NgModule({
+    imports: [
+        CoreFeaturesModule,
+    ],
+    providers: [
+        { provide: HTTP_INTERCEPTORS, useClass: CoreInterceptor, multi: true },
+        {
+            provide: CORE_SITE_SCHEMAS,
+            useValue: [
+                FILEPOOL_SITE_SCHEMA,
+                SITES_SITE_SCHEMA,
+                SYNC_SITE_SCHEMA,
+            ],
+            multi: true,
+        },
+    ],
+})
+export class CoreModule {
+
+    constructor(platform: Platform, injector: Injector) {
+        // Set the injector.
+        setSingletonsInjector(injector);
+
+        // Register a handler for platform ready.
+        CoreInit.instance.registerProcess({
+            name: 'CorePlatformReady',
+            priority: CoreInitDelegate.MAX_RECOMMENDED_PRIORITY + 400,
+            blocking: true,
+            load: async () => {
+                await platform.ready();
+            },
+        });
+
+        // Register the update manager as an init process.
+        CoreInit.instance.registerProcess(CoreUpdateManager.instance);
+
+        // Restore the user's session during the init process.
+        CoreInit.instance.registerProcess({
+            name: 'CoreRestoreSession',
+            priority: CoreInitDelegate.MAX_RECOMMENDED_PRIORITY + 200,
+            blocking: false,
+            load: CoreSites.instance.restoreSession.bind(CoreSites.instance),
+        });
+
+        // Register clear app tmp folder.
+        CoreInit.instance.registerProcess({
+            name: 'CoreClearTmpFolder',
+            priority: CoreInitDelegate.MAX_RECOMMENDED_PRIORITY + 150,
+            blocking: false,
+            load: CoreFile.instance.clearTmpFolder.bind(CoreFile.instance),
+        });
+
+        // Execute the init processes.
+        CoreInit.instance.executeInitProcesses();
+    }
+
+}
diff --git a/src/core/features/features.module.ts b/src/core/features/features.module.ts
new file mode 100644
index 000000000..ff3633baf
--- /dev/null
+++ b/src/core/features/features.module.ts
@@ -0,0 +1,32 @@
+// (C) Copyright 2015 Moodle Pty Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { NgModule } from '@angular/core';
+
+import { CoreCoursesModule } from './courses/courses.module';
+import { CoreEmulatorModule } from './emulator/emulator.module';
+import { CoreFileUploaderInitModule } from './fileuploader/fileuploader-init.module';
+import { CoreLoginModule } from './login/login.module';
+import { CoreSettingsInitModule } from './settings/settings-init.module';
+
+@NgModule({
+    imports: [
+        CoreEmulatorModule,
+        CoreLoginModule,
+        CoreCoursesModule,
+        CoreSettingsInitModule,
+        CoreFileUploaderInitModule,
+    ],
+})
+export class CoreFeaturesModule {}
diff --git a/src/core/features/search/components/search-box/search-box.ts b/src/core/features/search/components/search-box/search-box.ts
index 23ab9a6ee..dd2048831 100644
--- a/src/core/features/search/components/search-box/search-box.ts
+++ b/src/core/features/search/components/search-box/search-box.ts
@@ -19,7 +19,7 @@ import { CoreDomUtils } from '@services/utils/dom';
 import { CoreUtils } from '@services/utils/utils';
 import { CoreSearchHistory } from '../../services/search-history';
 import { Translate } from '@singletons/core.singletons';
-import { CoreSearchHistoryDBRecord } from '../../services/search.history.db';
+import { CoreSearchHistoryDBRecord } from '../../services/search-history-db';
 
 /**
  * Component to display a "search box".
diff --git a/src/core/features/search/search.module.ts b/src/core/features/search/search.module.ts
index 4557cc77a..a59da3976 100644
--- a/src/core/features/search/search.module.ts
+++ b/src/core/features/search/search.module.ts
@@ -13,7 +13,11 @@
 // limitations under the License.
 
 import { NgModule } from '@angular/core';
+
+import { CORE_SITE_SCHEMAS } from '@services/sites';
+
 import { CoreSearchComponentsModule } from './components/components.module';
+import { SITE_SCHEMA } from './services/search-history-db';
 
 @NgModule({
     declarations: [
@@ -23,6 +27,7 @@ import { CoreSearchComponentsModule } from './components/components.module';
     ],
     providers: [
         CoreSearchComponentsModule,
+        { provide: CORE_SITE_SCHEMAS, useValue: [SITE_SCHEMA], multi: true },
     ],
 })
 export class CoreSearchModule {}
diff --git a/src/core/features/search/services/search.history.db.ts b/src/core/features/search/services/search-history-db.ts
similarity index 90%
rename from src/core/features/search/services/search.history.db.ts
rename to src/core/features/search/services/search-history-db.ts
index abc79d8c9..19a1e8819 100644
--- a/src/core/features/search/services/search.history.db.ts
+++ b/src/core/features/search/services/search-history-db.ts
@@ -12,13 +12,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import { CoreSiteSchema, registerSiteSchema } from '@services/sites';
+import { CoreSiteSchema } from '@services/sites';
 
 /**
  * Database variables for CoreSearchHistory service.
  */
 export const SEARCH_HISTORY_TABLE_NAME = 'seach_history';
-const SITE_SCHEMA: CoreSiteSchema = {
+export const SITE_SCHEMA: CoreSiteSchema = {
     name: 'CoreSearchHistoryProvider',
     version: 1,
     tables: [
@@ -60,7 +60,3 @@ export type CoreSearchHistoryDBRecord = {
     searchedtext: string; // Text of the performed search.
     times: number; // Times search has been performed (if previously in history).
 };
-
-export const initCoreSearchHistoryDB = (): void => {
-    registerSiteSchema(SITE_SCHEMA);
-};
diff --git a/src/core/features/search/services/search-history.ts b/src/core/features/search/services/search-history.ts
index 9ed2afaa4..7aa98df67 100644
--- a/src/core/features/search/services/search-history.ts
+++ b/src/core/features/search/services/search-history.ts
@@ -16,7 +16,7 @@ import { Injectable } from '@angular/core';
 
 import { CoreSites } from '@services/sites';
 import { SQLiteDB } from '@classes/sqlitedb';
-import { CoreSearchHistoryDBRecord, SEARCH_HISTORY_TABLE_NAME } from './search.history.db';
+import { CoreSearchHistoryDBRecord, SEARCH_HISTORY_TABLE_NAME } from './search-history-db';
 import { makeSingleton } from '@singletons/core.singletons';
 
 /**
diff --git a/src/core/services/app.ts b/src/core/services/app.ts
index 8ced91397..a09eea202 100644
--- a/src/core/services/app.ts
+++ b/src/core/services/app.ts
@@ -40,7 +40,7 @@ import { DBNAME, SCHEMA_VERSIONS_TABLE_NAME, SCHEMA_VERSIONS_TABLE_SCHEMA, Schem
  * }
  * ```
  */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreAppProvider {
 
     protected db: SQLiteDB;
diff --git a/src/core/services/config.ts b/src/core/services/config.ts
index 9cdf15782..ed7d54f73 100644
--- a/src/core/services/config.ts
+++ b/src/core/services/config.ts
@@ -23,7 +23,7 @@ import { CONFIG_TABLE_NAME, APP_SCHEMA, ConfigDBEntry } from '@services/config.d
  * Factory to provide access to dynamic and permanent config and settings.
  * It should not be abused into a temporary storage.
  */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreConfigProvider {
 
     protected appDB: SQLiteDB;
diff --git a/src/core/services/cron.ts b/src/core/services/cron.ts
index e7c6e2fc7..a96fec9cb 100644
--- a/src/core/services/cron.ts
+++ b/src/core/services/cron.ts
@@ -28,7 +28,7 @@ import { APP_SCHEMA, CRON_TABLE_NAME, CronDBEntry } from '@services/cron.db';
 /*
  * Service to handle cron processes. The registered processes will be executed every certain time.
 */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreCronDelegate {
 
     // Constants.
diff --git a/src/core/services/db.ts b/src/core/services/db.ts
index ce0979c67..c02b1a416 100644
--- a/src/core/services/db.ts
+++ b/src/core/services/db.ts
@@ -21,7 +21,7 @@ import { makeSingleton, SQLite, Platform } from '@singletons/core.singletons';
 /**
  * This service allows interacting with the local database to store and retrieve data.
  */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreDbProvider {
 
     protected dbInstances: {[name: string]: SQLiteDB} = {};
diff --git a/src/core/services/file-helper.ts b/src/core/services/file-helper.ts
index da28831c8..e9b68c725 100644
--- a/src/core/services/file-helper.ts
+++ b/src/core/services/file-helper.ts
@@ -30,7 +30,7 @@ import { makeSingleton, Translate } from '@singletons/core.singletons';
 /**
  * Provider to provide some helper functions regarding files and packages.
  */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreFileHelperProvider {
 
     /**
diff --git a/src/core/services/file-session.ts b/src/core/services/file-session.ts
index 9cbdeadc9..c9e9fc661 100644
--- a/src/core/services/file-session.ts
+++ b/src/core/services/file-session.ts
@@ -26,7 +26,7 @@ import { makeSingleton } from '@singletons/core.singletons';
  * Every component can provide a File area identifier to indentify every file list on the session.
  * This value can be the activity id or a mix of name and numbers.
  */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreFileSessionProvider {
 
     protected files: {[siteId: string]: {[component: string]: {[id: string]: (CoreWSExternalFile | FileEntry)[]}}} = {};
diff --git a/src/core/services/file.ts b/src/core/services/file.ts
index f760f2d2f..2e9704fa0 100644
--- a/src/core/services/file.ts
+++ b/src/core/services/file.ts
@@ -66,7 +66,7 @@ export const enum CoreFileFormat {
 /**
  * Factory to interact with the file system.
  */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreFileProvider {
 
     // Formats to read a file.
diff --git a/src/core/services/filepool.db.ts b/src/core/services/filepool-db.ts
similarity index 98%
rename from src/core/services/filepool.db.ts
rename to src/core/services/filepool-db.ts
index 42c8a15b0..710584800 100644
--- a/src/core/services/filepool.db.ts
+++ b/src/core/services/filepool-db.ts
@@ -13,7 +13,7 @@
 // limitations under the License.
 
 import { CoreAppSchema } from '@services/app';
-import { CoreSiteSchema, registerSiteSchema } from '@services/sites';
+import { CoreSiteSchema } from '@services/sites';
 
 /**
  * Database variables for CoreFilepool service.
@@ -361,7 +361,3 @@ export type CoreFilepoolLinksRecord = {
     component: string; // Component name.
     componentId: number | string; // Component Id.
 };
-
-export const initCoreFilepoolDB = (): void => {
-    registerSiteSchema(SITE_SCHEMA);
-};
diff --git a/src/core/services/filepool.ts b/src/core/services/filepool.ts
index 0318b7f28..279d14239 100644
--- a/src/core/services/filepool.ts
+++ b/src/core/services/filepool.ts
@@ -46,7 +46,7 @@ import {
     CoreFilepoolPackageEntry,
     CoreFilepoolQueueEntry,
     CoreFilepoolQueueDBEntry,
-} from '@services/filepool.db';
+} from '@services/filepool-db';
 
 /*
  * Factory for handling downloading files and retrieve downloaded files.
@@ -57,7 +57,7 @@ import {
  * The two main goals of this is to keep the content available offline, and improve the user experience by caching
  * the content locally.
  */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreFilepoolProvider {
 
     // Constants.
diff --git a/src/core/services/geolocation.ts b/src/core/services/geolocation.ts
index 110b368e8..05214b1f2 100644
--- a/src/core/services/geolocation.ts
+++ b/src/core/services/geolocation.ts
@@ -19,7 +19,7 @@ import { CoreApp } from '@services/app';
 import { CoreError } from '@classes/errors/error';
 import { Geolocation, Diagnostic, makeSingleton } from '@singletons/core.singletons';
 
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreGeolocationProvider {
 
     /**
diff --git a/src/core/services/groups.ts b/src/core/services/groups.ts
index 3eb041db4..b82596a84 100644
--- a/src/core/services/groups.ts
+++ b/src/core/services/groups.ts
@@ -24,7 +24,7 @@ import { CoreCourseBase } from '@/types/global';
 /*
  * Service to handle groups.
 */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreGroupsProvider {
 
     // Group mode constants.
diff --git a/src/core/services/init.ts b/src/core/services/init.ts
index 5a8e042bd..feb39b7a3 100644
--- a/src/core/services/init.ts
+++ b/src/core/services/init.ts
@@ -48,7 +48,7 @@ export type CoreInitHandler = {
 /*
  * Provider for initialisation mechanisms.
  */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreInitDelegate {
 
     static readonly DEFAULT_PRIORITY = 100; // Default priority for init processes.
diff --git a/src/core/services/lang.ts b/src/core/services/lang.ts
index 571d4df81..e1e0d6879 100644
--- a/src/core/services/lang.ts
+++ b/src/core/services/lang.ts
@@ -25,7 +25,7 @@ import * as moment from 'moment';
 /*
  * Service to handle language features, like changing the current language.
 */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreLangProvider {
 
     protected fallbackLanguage = 'en'; // Always use English as fallback language since it contains all strings.
diff --git a/src/core/services/local-notifications.ts b/src/core/services/local-notifications.ts
index c20ca3217..353affdee 100644
--- a/src/core/services/local-notifications.ts
+++ b/src/core/services/local-notifications.ts
@@ -39,7 +39,7 @@ import {
 /**
  * Service to handle local notifications.
  */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreLocalNotificationsProvider {
 
     protected logger: CoreLogger;
diff --git a/src/core/services/plugin-file.delegate.ts b/src/core/services/plugin-file.delegate.ts
index 3c46e0ab6..cfd57613b 100644
--- a/src/core/services/plugin-file.delegate.ts
+++ b/src/core/services/plugin-file.delegate.ts
@@ -24,7 +24,7 @@ import { makeSingleton } from '@singletons/core.singletons';
 /**
  * Delegate to register pluginfile information handlers.
  */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CorePluginFileDelegate extends CoreDelegate<CorePluginFileHandler> {
 
     protected handlerNameProperty = 'component';
diff --git a/src/core/services/sites.db.ts b/src/core/services/sites-db.ts
similarity index 97%
rename from src/core/services/sites.db.ts
rename to src/core/services/sites-db.ts
index 83c6e8027..a6eea9464 100644
--- a/src/core/services/sites.db.ts
+++ b/src/core/services/sites-db.ts
@@ -13,7 +13,7 @@
 // limitations under the License.
 
 import { CoreAppSchema } from '@services/app';
-import { CoreSiteSchema, registerSiteSchema } from '@services/sites';
+import { CoreSiteSchema } from '@services/sites';
 import { SQLiteDB, SQLiteDBTableSchema } from '@classes/sqlitedb';
 import { CoreSite } from '@classes/site';
 
@@ -227,7 +227,3 @@ export type SchemaVersionsDBEntry = {
     name: string;
     version: number;
 };
-
-export const initCoreSitesDB = (): void => {
-    registerSiteSchema(SITE_SCHEMA);
-};
diff --git a/src/core/services/sites.ts b/src/core/services/sites.ts
index d60e0d026..3d8d52de2 100644
--- a/src/core/services/sites.ts
+++ b/src/core/services/sites.ts
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import { Injectable } from '@angular/core';
+import { Inject, Injectable, InjectionToken, Optional } from '@angular/core';
 import { Md5 } from 'ts-md5/dist/md5';
 import { timeout } from 'rxjs/operators';
 
@@ -47,25 +47,17 @@ import {
     SiteDBEntry,
     CurrentSiteDBEntry,
     SchemaVersionsDBEntry,
-} from '@services/sites.db';
+} from '@services/sites-db';
+import { CoreArray } from '../singletons/array';
 
-
-// Schemas for site tables. Other providers can add schemas in here using the registerSiteSchema function.
-const siteSchemas: { [name: string]: CoreRegisteredSiteSchema } = {};
-export const registerSiteSchema = (schema: CoreSiteSchema): void => {
-    siteSchemas[schema.name] = schema;
-};
+export const CORE_SITE_SCHEMAS = new InjectionToken('CORE_SITE_SCHEMAS');
 
 /*
  * Service to manage and interact with sites.
  * It allows creating tables in the databases of all sites. Each service or component should be responsible of creating
- * their own database tables. Example:
- *
- * import { registerSiteSchema } from '@services/sites';
- *
- * registerSiteSchema(tableSchema);
+ * their own database tables calling the registerCoreSiteSchema method.
 */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreSitesProvider {
 
     // Constants to validate a site version.
@@ -84,11 +76,19 @@ export class CoreSitesProvider {
     protected appDB: SQLiteDB;
     protected dbReady: Promise<void>; // Promise resolved when the app DB is initialized.
     protected siteSchemasMigration: { [siteId: string]: Promise<void> } = {};
+    protected siteSchemas: { [name: string]: CoreRegisteredSiteSchema } = {};
     protected pluginsSiteSchemas: { [name: string]: CoreRegisteredSiteSchema } = {};
 
-    constructor() {
+    constructor(@Optional() @Inject(CORE_SITE_SCHEMAS) siteSchemas: CoreSiteSchema[][] = []) {
         this.logger = CoreLogger.getInstance('CoreSitesProvider');
+        this.siteSchemas = CoreArray.flatten(siteSchemas).reduce(
+            (siteSchemas, schema) => {
+                siteSchemas[schema.name] = schema;
 
+                return siteSchemas;
+            },
+            this.siteSchemas,
+        );
         this.appDB = CoreApp.instance.getDB();
         this.dbReady = CoreApp.instance.createTablesFromSchema(APP_SCHEMA).catch(() => {
             // Ignore errors.
@@ -1446,7 +1446,7 @@ export class CoreSitesProvider {
     /**
      * Register a site schema in current site.
      * This function is meant for site plugins to create DB tables in current site. Tables created from within the app
-     * whould use the registerSiteSchema function exported in this same file.
+     * should use the registerCoreSiteSchema method instead.
      *
      * @param schema The schema to register.
      * @return Promise resolved when done.
@@ -1489,7 +1489,7 @@ export class CoreSitesProvider {
 
         // First create tables not registerd with name/version.
         const promise = site.getDb().createTableFromSchema(SCHEMA_VERSIONS_TABLE_SCHEMA)
-            .then(() => this.applySiteSchemas(site, siteSchemas));
+            .then(() => this.applySiteSchemas(site, this.siteSchemas));
 
         this.siteSchemasMigration[site.id] = promise;
 
@@ -1602,7 +1602,7 @@ export class CoreSitesProvider {
      */
     getSiteTableSchemasToClear(site: CoreSite): string[] {
         let reset: string[] = [];
-        const schemas = Object.values(siteSchemas).concat(Object.values(this.pluginsSiteSchemas));
+        const schemas = Object.values(this.siteSchemas).concat(Object.values(this.pluginsSiteSchemas));
 
         schemas.forEach((schema) => {
             if (schema.canBeCleared && (!schema.siteId || site.getId() == schema.siteId)) {
diff --git a/src/core/services/sync.db.ts b/src/core/services/sync-db.ts
similarity index 88%
rename from src/core/services/sync.db.ts
rename to src/core/services/sync-db.ts
index 47d5dc900..c30db03c2 100644
--- a/src/core/services/sync.db.ts
+++ b/src/core/services/sync-db.ts
@@ -12,13 +12,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import { CoreSiteSchema, registerSiteSchema } from '@services/sites';
+import { CoreSiteSchema } from '@services/sites';
 
 /**
  * Database variables for CoreSync service.
  */
 export const SYNC_TABLE_NAME = 'sync';
-const SITE_SCHEMA: CoreSiteSchema = {
+export const SITE_SCHEMA: CoreSiteSchema = {
     name: 'CoreSyncProvider',
     version: 1,
     tables: [
@@ -55,7 +55,3 @@ export type CoreSyncRecord = {
     time: number;
     warnings: string;
 };
-
-export const initCoreSyncDB = (): void => {
-    registerSiteSchema(SITE_SCHEMA);
-};
diff --git a/src/core/services/sync.ts b/src/core/services/sync.ts
index 16383a6f7..2b7f4a32e 100644
--- a/src/core/services/sync.ts
+++ b/src/core/services/sync.ts
@@ -16,12 +16,12 @@ import { Injectable } from '@angular/core';
 import { CoreEvents } from '@singletons/events';
 import { CoreSites } from '@services/sites';
 import { makeSingleton } from '@singletons/core.singletons';
-import { SYNC_TABLE_NAME, CoreSyncRecord } from '@services/sync.db';
+import { SYNC_TABLE_NAME, CoreSyncRecord } from '@services/sync-db';
 
 /*
  * Service that provides some features regarding synchronization.
 */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreSyncProvider {
 
     // Store blocked sync objects.
diff --git a/src/core/services/update-manager.ts b/src/core/services/update-manager.ts
index 4c8eca8d9..78ee29cdd 100644
--- a/src/core/services/update-manager.ts
+++ b/src/core/services/update-manager.ts
@@ -27,7 +27,7 @@ const VERSION_APPLIED = 'version_applied';
  *
  * This service handles processes that need to be run when updating the app, like migrate Ionic 1 database data to Ionic 3.
  */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreUpdateManagerProvider implements CoreInitHandler {
 
     // Data for init delegate.
diff --git a/src/core/services/utils/dom.ts b/src/core/services/utils/dom.ts
index eb6ac5042..0e7473e1f 100644
--- a/src/core/services/utils/dom.ts
+++ b/src/core/services/utils/dom.ts
@@ -38,7 +38,7 @@ import { CoreLogger } from '@singletons/logger';
 /*
  * "Utils" service with helper functions for UI, DOM elements and HTML code.
  */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreDomUtilsProvider {
 
     protected readonly INSTANCE_ID_ATTR_NAME = 'core-instance-id';
diff --git a/src/core/services/utils/iframe.ts b/src/core/services/utils/iframe.ts
index b6e09d003..3f0541a4e 100644
--- a/src/core/services/utils/iframe.ts
+++ b/src/core/services/utils/iframe.ts
@@ -42,7 +42,7 @@ type CoreFrameElement = (HTMLIFrameElement | HTMLFrameElement | HTMLObjectElemen
 /*
  * "Utils" service with helper functions for iframes, embed and similar.
  */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreIframeUtilsProvider {
 
     static readonly FRAME_TAGS = ['iframe', 'frame', 'object', 'embed'];
diff --git a/src/core/services/utils/mimetype.ts b/src/core/services/utils/mimetype.ts
index bbf1219c4..4f400f8c5 100644
--- a/src/core/services/utils/mimetype.ts
+++ b/src/core/services/utils/mimetype.ts
@@ -44,7 +44,7 @@ const EXTENSION_REGEX = /^[a-z0-9]+$/;
 /*
  * "Utils" service with helper functions for mimetypes and extensions.
  */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreMimetypeUtilsProvider {
 
     protected logger: CoreLogger;
diff --git a/src/core/services/utils/text.ts b/src/core/services/utils/text.ts
index dcaf3c00f..a5a81301d 100644
--- a/src/core/services/utils/text.ts
+++ b/src/core/services/utils/text.ts
@@ -37,7 +37,7 @@ export type CoreTextErrorObject = {
 /*
  * "Utils" service with helper functions for text.
 */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreTextUtilsProvider {
 
     // List of regular expressions to convert the old nomenclature to new nomenclature for disabled features.
diff --git a/src/core/services/utils/time.ts b/src/core/services/utils/time.ts
index 0cdbfba45..345e10008 100644
--- a/src/core/services/utils/time.ts
+++ b/src/core/services/utils/time.ts
@@ -21,7 +21,7 @@ import { makeSingleton, Translate } from '@singletons/core.singletons';
 /*
  * "Utils" service with helper functions for date and time.
 */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreTimeUtilsProvider {
 
     protected static readonly FORMAT_REPLACEMENTS = { // To convert PHP strf format to Moment format.
diff --git a/src/core/services/utils/url.ts b/src/core/services/utils/url.ts
index 4f0917d0c..fb5489abe 100644
--- a/src/core/services/utils/url.ts
+++ b/src/core/services/utils/url.ts
@@ -23,7 +23,7 @@ import { CoreUrl } from '@singletons/url';
 /*
  * "Utils" service with helper functions for URLs.
  */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreUrlUtilsProvider {
 
     /**
diff --git a/src/core/services/utils/utils.ts b/src/core/services/utils/utils.ts
index 676f9855a..be7c87793 100644
--- a/src/core/services/utils/utils.ts
+++ b/src/core/services/utils/utils.ts
@@ -36,7 +36,7 @@ type TreeNode<T> = T & { children: TreeNode<T>[] };
 /*
  * "Utils" service with helper functions.
  */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreUtilsProvider {
 
     protected readonly DONT_CLONE = ['[object FileEntry]', '[object DirectoryEntry]', '[object DOMFileSystem]'];
diff --git a/src/core/services/ws.ts b/src/core/services/ws.ts
index 9e0d211eb..cd7b37868 100644
--- a/src/core/services/ws.ts
+++ b/src/core/services/ws.ts
@@ -40,7 +40,7 @@ import { CoreAjaxWSError } from '@classes/errors/ajaxwserror';
 /**
  * This service allows performing WS calls and download/upload files.
  */
-@Injectable()
+@Injectable({ providedIn: 'root' })
 export class CoreWSProvider {
 
     protected logger: CoreLogger;