diff --git a/pwa.php b/pwa.php
index b1f19d415..1390cec9d 100644
--- a/pwa.php
+++ b/pwa.php
@@ -72,6 +72,7 @@
 require_once PWA_PLUGIN_DIR . '/wp-includes/integrations/class-wp-service-worker-scripts-integration.php';
 require_once PWA_PLUGIN_DIR . '/wp-includes/integrations/class-wp-service-worker-styles-integration.php';
 require_once PWA_PLUGIN_DIR . '/wp-includes/integrations/class-wp-service-worker-fonts-integration.php';
+require_once PWA_PLUGIN_DIR . '/wp-includes/integrations/class-wp-service-worker-admin-assets-integration.php';
 
 /** WordPress Service Worker Functions */
 require_once PWA_PLUGIN_DIR . '/wp-includes/service-workers.php';
diff --git a/tests/test-class-wp-service-workers.php b/tests/test-class-wp-service-workers.php
index fd415ae86..ed485a976 100644
--- a/tests/test-class-wp-service-workers.php
+++ b/tests/test-class-wp-service-workers.php
@@ -64,7 +64,7 @@ public function test_serve_request_front() {
 		add_action( 'wp_admin_service_worker', array( $this, 'register_foo_sw' ) );
 
 		ob_start();
-		wp_service_workers()->serve_request( WP_Service_Workers::SCOPE_FRONT );
+		wp_service_workers()->serve_request();
 		$output = ob_get_clean();
 		$this->assertContains( $this->return_foo_sw(), $output );
 		$this->assertContains( $this->return_bar_sw(), $output );
@@ -87,7 +87,8 @@ public function test_serve_request_admin() {
 		add_action( 'wp_admin_service_worker', array( $this, 'register_foo_sw' ) );
 
 		ob_start();
-		wp_service_workers()->serve_request( WP_Service_Workers::SCOPE_ADMIN );
+		set_current_screen( 'admin-ajax' );
+		wp_service_workers()->serve_request();
 		$output = ob_get_clean();
 
 		$this->assertContains( $this->return_foo_sw(), $output );
@@ -98,17 +99,6 @@ public function test_serve_request_admin() {
 		);
 	}
 
-	/**
-	 * Test serve_request for invalid scope.
-	 *
-	 * @covers WP_Service_Workers::serve_request()
-	 */
-	public function test_serve_request_invalid_scope() {
-		ob_start();
-		wp_service_workers()->serve_request( 'bad' );
-		$this->assertContains( 'invalid_scope_requested', ob_get_clean() );
-	}
-
 	/**
 	 * Test serve_request for bad src callback.
 	 *
@@ -125,7 +115,8 @@ public function test_serve_request_bad_src_callback() {
 		);
 
 		ob_start();
-		wp_service_workers()->serve_request( WP_Service_Workers::SCOPE_ADMIN );
+		set_current_screen( 'admin-ajax' );
+		wp_service_workers()->serve_request();
 		$output = ob_get_clean();
 
 		$this->assertContains( 'Service worker src is invalid', $output );
@@ -147,7 +138,7 @@ public function test_serve_request_bad_src_url() {
 		);
 
 		ob_start();
-		wp_service_workers()->serve_request( WP_Service_Workers::SCOPE_FRONT );
+		wp_service_workers()->serve_request();
 		$output = ob_get_clean();
 
 		$this->assertContains( 'Service worker src is invalid', $output );
diff --git a/wp-includes/class-wp-service-worker-scripts.php b/wp-includes/class-wp-service-worker-scripts.php
index 489e2866f..abfedc90d 100644
--- a/wp-includes/class-wp-service-worker-scripts.php
+++ b/wp-includes/class-wp-service-worker-scripts.php
@@ -13,8 +13,8 @@
  *
  * @see WP_Dependencies
  *
- * @method WP_Service_Worker_Precaching_Routes_Component precaching_routes()
- * @method WP_Service_Worker_Caching_Routes_Component    caching_routes()
+ * @method WP_Service_Worker_Precaching_Routes precaching_routes()
+ * @method WP_Service_Worker_Caching_Routes caching_routes()
  */
 class WP_Service_Worker_Scripts extends WP_Scripts implements WP_Service_Worker_Registry {
 
diff --git a/wp-includes/class-wp-service-workers.php b/wp-includes/class-wp-service-workers.php
index 47c7e78f8..2893d4856 100644
--- a/wp-includes/class-wp-service-workers.php
+++ b/wp-includes/class-wp-service-workers.php
@@ -78,31 +78,19 @@ public function get_registry() {
 	/**
 	 * Get the current scope for the service worker request.
 	 *
-	 * @global WP $wp
-	 *
-	 * @return int Scope. Either SCOPE_FRONT, SCOPE_ADMIN, or if neither then 0.
+	 * @todo We don't really need this. A simple call to is_admin() is all that is required.
+	 * @return int Scope. Either SCOPE_FRONT or SCOPE_ADMIN.
 	 */
 	public function get_current_scope() {
-		global $wp;
-		if ( ! isset( $wp->query_vars[ self::QUERY_VAR ] ) || ! is_numeric( $wp->query_vars[ self::QUERY_VAR ] ) ) {
-			return 0;
-		}
-		$scope = (int) $wp->query_vars[ self::QUERY_VAR ];
-		if ( self::SCOPE_FRONT === $scope ) {
-			return self::SCOPE_FRONT;
-		} elseif ( self::SCOPE_ADMIN === $scope ) {
-			return self::SCOPE_ADMIN;
-		}
-		return 0;
+		return is_admin() ? self::SCOPE_ADMIN : self::SCOPE_FRONT;
 	}
 
 	/**
 	 * Get service worker logic for scope.
 	 *
 	 * @see wp_service_worker_loaded()
-	 * @param int $scope Scope of the Service Worker.
 	 */
-	public function serve_request( $scope ) {
+	public function serve_request() {
 		/*
 		 * Per Workbox <https://developers.google.com/web/tools/workbox/guides/service-worker-checklist#cache-control_of_your_service_worker_file>:
 		 * "Generally, most developers will want to set the Cache-Control header to no-cache,
@@ -114,7 +102,7 @@ public function serve_request( $scope ) {
 
 		@header( 'Content-Type: text/javascript; charset=utf-8' ); // phpcs:ignore Generic.PHP.NoSilencedErrors.Discouraged, WordPress.PHP.NoSilencedErrors.Discouraged
 
-		if ( self::SCOPE_FRONT === $scope ) {
+		if ( ! is_admin() ) {
 			wp_enqueue_scripts();
 
 			/**
@@ -134,7 +122,13 @@ public function serve_request( $scope ) {
 			 * @param WP_Service_Worker_Scripts $scripts Instance to register service worker behavior with.
 			 */
 			do_action( 'wp_front_service_worker', $this->scripts );
-		} elseif ( self::SCOPE_ADMIN === $scope ) {
+		} else {
+			$hook_name = 'service-worker';
+			set_current_screen( $hook_name );
+
+			/** This action is documented in wp-admin/admin-header.php */
+			do_action( 'admin_enqueue_scripts', $hook_name );
+
 			/**
 			 * Fires before serving the wp-admin service worker, when its scripts should be registered, caching routes established, and assets precached.
 			 *
@@ -145,13 +139,7 @@ public function serve_request( $scope ) {
 			do_action( 'wp_admin_service_worker', $this->scripts );
 		}
 
-		if ( self::SCOPE_FRONT !== $scope && self::SCOPE_ADMIN !== $scope ) {
-			status_header( 400 );
-			echo '/* invalid_scope_requested */';
-			return;
-		}
-
-		printf( "/* PWA v%s */\n\n", esc_html( PWA_VERSION ) );
+		printf( "/* PWA v%s-%s */\n\n", esc_html( PWA_VERSION ), is_admin() ? 'admin' : 'front' );
 
 		ob_start();
 		$this->scripts->do_items( array_keys( $this->scripts->registered ) );
diff --git a/wp-includes/components/class-wp-service-worker-error-response-component.php b/wp-includes/components/class-wp-service-worker-error-response-component.php
index 0dfd958cc..f728960c6 100644
--- a/wp-includes/components/class-wp-service-worker-error-response-component.php
+++ b/wp-includes/components/class-wp-service-worker-error-response-component.php
@@ -39,8 +39,7 @@ public function serve( WP_Service_Worker_Scripts $scripts ) {
 		// Ensure the user-specific offline/500 pages are precached, and thet they update when user logs out or switches to another user.
 		$revision .= sprintf( ';user-%d', get_current_user_id() );
 
-		$current_scope = wp_service_workers()->get_current_scope();
-		if ( WP_Service_Workers::SCOPE_FRONT === $current_scope ) {
+		if ( ! is_admin() ) {
 			$offline_error_template_file  = pwa_locate_template( array( 'offline.php', 'error.php' ) );
 			$offline_error_precache_entry = array(
 				'url'      => add_query_arg( 'wp_error_template', 'offline', home_url( '/' ) ),
@@ -117,7 +116,7 @@ public function serve( WP_Service_Worker_Scripts $scripts ) {
 		}
 
 		$blacklist_patterns = array();
-		if ( WP_Service_Workers::SCOPE_FRONT === $current_scope ) {
+		if ( ! is_admin() ) {
 			$blacklist_patterns[] = '^' . preg_quote( untrailingslashit( wp_parse_url( admin_url(), PHP_URL_PATH ) ), '/' ) . '($|\?.*|/.*)';
 		}
 
diff --git a/wp-includes/components/class-wp-service-worker-precaching-routes.php b/wp-includes/components/class-wp-service-worker-precaching-routes.php
index fa6deb343..dc5e24387 100644
--- a/wp-includes/components/class-wp-service-worker-precaching-routes.php
+++ b/wp-includes/components/class-wp-service-worker-precaching-routes.php
@@ -45,6 +45,29 @@ public function register( $url, $args = array() ) {
 		);
 	}
 
+	/**
+	 * Register Emoji script.
+	 *
+	 * Short-circuit if SCRIPT_DEBUG (hence file not built) or print_emoji_detection_script has been removed.
+	 *
+	 * @since 0.2
+	 *
+	 * @return bool Whether emoji script was registered.
+	 */
+	public function register_emoji_script() {
+		if ( SCRIPT_DEBUG || false === has_action( is_admin() ? 'admin_print_scripts' : 'wp_head', 'print_emoji_detection_script' ) ) {
+			return false;
+		}
+
+		$this->register(
+			includes_url( 'js/wp-emoji-release.min.js' ),
+			array(
+				'revision' => get_bloginfo( 'version' ),
+			)
+		);
+		return true;
+	}
+
 	/**
 	 * Gets all registered routes.
 	 *
diff --git a/wp-includes/default-filters.php b/wp-includes/default-filters.php
index 824fc5bdb..d89a1d04a 100644
--- a/wp-includes/default-filters.php
+++ b/wp-includes/default-filters.php
@@ -13,8 +13,12 @@
 }
 
 add_action( 'parse_query', 'wp_service_worker_loaded' );
+add_action( 'wp_ajax_wp_service_worker', 'wp_ajax_wp_service_worker' );
+add_action( 'wp_ajax_nopriv_wp_service_worker', 'wp_ajax_wp_service_worker' );
 add_action( 'parse_query', 'wp_hide_admin_bar_offline' );
 
 add_action( 'wp_head', 'wp_add_error_template_no_robots' );
 add_action( 'error_head', 'wp_add_error_template_no_robots' );
 add_action( 'wp_default_service_workers', 'wp_default_service_workers' );
+
+add_action( 'admin_init', 'wp_disable_script_concatenation' );
diff --git a/wp-includes/integrations/class-wp-service-worker-admin-assets-integration.php b/wp-includes/integrations/class-wp-service-worker-admin-assets-integration.php
new file mode 100644
index 000000000..cf6335c17
--- /dev/null
+++ b/wp-includes/integrations/class-wp-service-worker-admin-assets-integration.php
@@ -0,0 +1,148 @@
+<?php
+/**
+ * WP_Service_Worker_Admin_Assets_Integration class.
+ *
+ * @package PWA
+ */
+
+/**
+ * Class representing the admin assets service worker integration.
+ *
+ * @since 0.2
+ */
+class WP_Service_Worker_Admin_Assets_Integration extends WP_Service_Worker_Base_Integration {
+
+	/**
+	 * Registers the integration functionality.
+	 *
+	 * @since 0.2
+	 *
+	 * @param WP_Service_Worker_Scripts $scripts Instance to register service worker behavior with.
+	 */
+	public function register( WP_Service_Worker_Scripts $scripts ) {
+		if ( ! function_exists( 'list_files' ) ) {
+			require_once ABSPATH . 'wp-admin/includes/file.php';
+		}
+
+		$admin_dir    = ABSPATH . 'wp-admin/';
+		$admin_images = list_files( $admin_dir . 'images/' );
+		$inc_images   = list_files( ABSPATH . WPINC . '/images/' );
+
+		// @todo This should not enqueue TinyMCE if rich editing is disabled?
+		$this->flag_admin_assets_with_precache( wp_scripts()->registered );
+		$this->flag_admin_assets_with_precache( wp_styles()->registered );
+
+		$routes = array_merge(
+			$this->get_routes_from_file_list( $admin_images, 'wp-admin' ),
+			$this->get_routes_from_file_list( $inc_images, 'wp-includes' ),
+			$this->get_woff_file_list(),
+			$this->get_tinymce_file_list()
+		);
+
+		foreach ( $routes as $options ) {
+			if ( isset( $options['url'] ) ) {
+				$url = $options['url'];
+				unset( $options['url'] );
+				$scripts->precaching_routes()->register( $url, $options );
+			}
+		}
+	}
+
+	/**
+	 * Defines the scope of this integration by setting `$this->scope`.
+	 *
+	 * @since 0.2
+	 */
+	protected function define_scope() {
+		$this->scope = WP_Service_Workers::SCOPE_ADMIN;
+	}
+
+	/**
+	 * Flags admin assets with precache.
+	 *
+	 * @param _WP_Dependency[] $dependencies Array of _WP_Dependency objects.
+	 * @return array Array of routes.
+	 */
+	protected function flag_admin_assets_with_precache( $dependencies ) {
+		$routes = array();
+		foreach ( $dependencies as $handle => $params ) {
+
+			// Only precache scripts from wp-admin and wp-includes (and Gutenberg).
+			if ( preg_match( '#/(wp-admin|wp-includes|wp-content/plugins/gutenberg)/#', $params->src ) ) {
+				$params->add_data( 'precache', true );
+			}
+		}
+		return $routes;
+	}
+
+	/**
+	 * Get static list of .woff files to precache.
+	 *
+	 * @todo These should be also available to the frontend. So this should go into WP_Service_Worker_Precaching_Routes.
+	 * @return array
+	 */
+	protected function get_woff_file_list() {
+		return array(
+			array(
+				'revision' => get_bloginfo( 'version' ),
+				'url'      => '/wp-includes/fonts/dashicons.woff',
+			),
+			array(
+				'revision' => get_bloginfo( 'version' ),
+				'url'      => '/wp-includes/js/tinymce/skins/lightgray/fonts/tinymce-small.woff',
+			),
+			array(
+				'revision' => get_bloginfo( 'version' ),
+				'url'      => '/wp-includes/js/tinymce/skins/lightgray/fonts/tinymce.woff',
+			),
+		);
+	}
+
+	/**
+	 * Get list of TinyMCE files for precaching.
+	 *
+	 * @return array Routes.
+	 */
+	protected function get_tinymce_file_list() {
+		global $tinymce_version;
+		$tinymce_routes = array();
+		$tinymce_files  = list_files( ABSPATH . WPINC . '/js/tinymce/' );
+
+		foreach ( $tinymce_files as $tinymce_file ) {
+			$basename = basename( $tinymce_file );
+			if ( preg_match( '#\.min\.(css|js)$#', $tinymce_file ) ) {
+				$url = includes_url( preg_replace( '/.*' . WPINC . '/', '', $tinymce_file ) );
+
+				$tinymce_routes[] = array(
+					'url'      => $url,
+					'revision' => $tinymce_version,
+				);
+			}
+		}
+		return $tinymce_routes;
+	}
+
+	/**
+	 * Get routes from file paths list.
+	 *
+	 * @param array  $list List of file paths.
+	 * @param string $folder Folder -- either 'wp-admin' or 'wp-includes'.
+	 * @return array List of routes.
+	 */
+	protected function get_routes_from_file_list( $list, $folder ) {
+		$routes = array();
+		foreach ( $list as $filename ) {
+			$ext = pathinfo( $filename, PATHINFO_EXTENSION );
+			if ( ! in_array( $ext, array( 'png', 'gif', 'svg' ), true ) ) {
+				continue;
+			}
+
+			$routes[] = array(
+				'url'      => strstr( $filename, '/' . $folder ),
+				'revision' => get_bloginfo( 'version' ),
+			);
+		}
+
+		return $routes;
+	}
+}
diff --git a/wp-includes/integrations/class-wp-service-worker-base-integration.php b/wp-includes/integrations/class-wp-service-worker-base-integration.php
index 4513c5f9b..f4adc5f27 100644
--- a/wp-includes/integrations/class-wp-service-worker-base-integration.php
+++ b/wp-includes/integrations/class-wp-service-worker-base-integration.php
@@ -77,4 +77,27 @@ protected function get_attachment_image_urls( $attachment_id, $image_size ) {
 
 		return array();
 	}
+
+	/**
+	 * Determines whether a URL is for a local file.
+	 *
+	 * @since 0.2
+	 *
+	 * @param string $url URL.
+	 * @return bool Whether local.
+	 */
+	protected function is_local_file_url( $url ) {
+		$re_proto = '#^\w+(?://)#';
+		$url      = preg_replace( $re_proto, '', $url );
+		$home_url = preg_replace( $re_proto, '', home_url( '/' ) );
+		$site_url = preg_replace( $re_proto, '', site_url( '/' ) );
+
+		return (
+			'/' === substr( $url, 0, 1 )
+			||
+			substr( $url, 0, strlen( $home_url ) ) === $home_url
+			||
+			substr( $url, 0, strlen( $site_url ) ) === $site_url
+		);
+	}
 }
diff --git a/wp-includes/integrations/class-wp-service-worker-scripts-integration.php b/wp-includes/integrations/class-wp-service-worker-scripts-integration.php
index bbc6c1fde..51c763f83 100644
--- a/wp-includes/integrations/class-wp-service-worker-scripts-integration.php
+++ b/wp-includes/integrations/class-wp-service-worker-scripts-integration.php
@@ -73,10 +73,13 @@ public function register( WP_Service_Worker_Scripts $scripts ) {
 			/** This filter is documented in wp-includes/class.wp-scripts.php */
 			$url = apply_filters( 'script_loader_src', $url, $handle );
 
-			if ( $url ) {
+			if ( $url && $this->is_local_file_url( $url ) ) {
 				$scripts->precaching_routes()->register( $url, $revision );
 			}
 		}
+
+		$scripts->precaching_routes()->register_emoji_script();
+
 		wp_scripts()->to_do = $original_to_do; // Restore original scripts to do.
 	}
 
diff --git a/wp-includes/integrations/class-wp-service-worker-styles-integration.php b/wp-includes/integrations/class-wp-service-worker-styles-integration.php
index 8a6bc921f..f4f4d8fc9 100644
--- a/wp-includes/integrations/class-wp-service-worker-styles-integration.php
+++ b/wp-includes/integrations/class-wp-service-worker-styles-integration.php
@@ -73,7 +73,7 @@ public function register( WP_Service_Worker_Scripts $scripts ) {
 			/** This filter is documented in wp-includes/class.wp-styles.php */
 			$url = apply_filters( 'style_loader_src', $url, $handle );
 
-			if ( $url ) {
+			if ( $url && $this->is_local_file_url( $url ) ) {
 				$scripts->precaching_routes()->register( $url, $revision );
 			}
 		}
diff --git a/wp-includes/js/service-worker-precaching.js b/wp-includes/js/service-worker-precaching.js
index 934b5029c..93aadc2e0 100644
--- a/wp-includes/js/service-worker-precaching.js
+++ b/wp-includes/js/service-worker-precaching.js
@@ -8,6 +8,7 @@
 	wp.serviceWorker.precaching.addRoute( {
 		ignoreUrlParametersMatching: [
 			/^utm_/,
+			/^wp-mce-/,
 			/^ver$/
 		]
 		// @todo Add urlManipulation which allows for the list of ignoreUrlParametersMatching to be supplied with each entry.
diff --git a/wp-includes/service-workers.php b/wp-includes/service-workers.php
index 320e49605..4a0f231f3 100644
--- a/wp-includes/service-workers.php
+++ b/wp-includes/service-workers.php
@@ -91,10 +91,17 @@ function wp_get_service_worker_url( $scope = WP_Service_Workers::SCOPE_FRONT ) {
 		$scope = WP_Service_Workers::SCOPE_FRONT;
 	}
 
-	return add_query_arg(
-		array( WP_Service_Workers::QUERY_VAR => $scope ),
-		home_url( '/', 'https' )
-	);
+	if ( WP_Service_Workers::SCOPE_FRONT === $scope ) {
+		return add_query_arg(
+			array( WP_Service_Workers::QUERY_VAR => $scope ),
+			home_url( '/', 'https' )
+		);
+	} else {
+		return add_query_arg(
+			array( 'action' => WP_Service_Workers::QUERY_VAR ),
+			admin_url( 'admin-ajax.php' )
+		);
+	}
 }
 
 /**
@@ -131,7 +138,9 @@ function wp_print_service_workers() {
 					navigator.serviceWorker.register(
 						<?php echo wp_json_encode( wp_get_service_worker_url( $name ) ); ?>,
 						<?php echo wp_json_encode( compact( 'scope' ) ); ?>
-					);
+					).then( function() {
+						document.cookie = 'wordpress_sw_installed=1; path=/; expires=Fri, 31 Dec 9999 23:59:59 GMT; secure; samesite=strict';
+					} );
 				<?php } ?>
 			} );
 		}
@@ -170,19 +179,33 @@ function wp_print_service_worker_error_details_script( $callback ) {
 }
 
 /**
- * If it's a service worker script page, display that.
+ * Serve the service worker for the frontend if requested.
  *
  * @since 0.1
  * @see rest_api_loaded()
+ * @see wp_ajax_wp_service_worker()
  */
 function wp_service_worker_loaded() {
-	$scope = wp_service_workers()->get_current_scope();
-	if ( 0 !== $scope ) {
-		wp_service_workers()->serve_request( $scope );
+	global $wp;
+	if ( isset( $wp->query_vars[ WP_Service_Workers::QUERY_VAR ] ) ) {
+		wp_service_workers()->serve_request();
 		exit;
 	}
 }
 
+/**
+ * Serve admin service worker.
+ *
+ * This will be moved to wp-admin/includes/admin-actions.php
+ *
+ * @since 0.2
+ * @see wp_service_worker_loaded()
+ */
+function wp_ajax_wp_service_worker() {
+	wp_service_workers()->serve_request();
+	exit;
+}
+
 /**
  * JSON-encodes with pretty printing.
  *
@@ -217,6 +240,10 @@ function wp_default_service_workers( $scripts ) {
 		'wp-fonts'             => new WP_Service_Worker_Fonts_Integration(),
 	);
 
+	if ( ! SCRIPT_DEBUG ) {
+		$integrations['wp-admin-assets'] = new WP_Service_Worker_Admin_Assets_Integration();
+	}
+
 	/**
 	 * Filters the service worker integrations to initialize.
 	 *
@@ -270,3 +297,24 @@ function wp_default_service_workers( $scripts ) {
 		}
 	}
 }
+
+/**
+ * Disables concatenating scripts to leverage caching the assets via Service Worker instead.
+ */
+function wp_disable_script_concatenation() {
+	global $concatenate_scripts;
+
+	/*
+	 * This cookie is set when the service worker registers successfully, avoiding unnecessary result
+	 * for browsers that don't support service workers. Note that concatenation only applies in the admin,
+	 * for authenticated users without full-page caching.
+	*/
+	if ( isset( $_COOKIE['wordpress_sw_installed'] ) ) {
+		$concatenate_scripts = false; // WPCS: Override OK.
+	}
+
+	// @todo This is just here for debugging purposes.
+	if ( isset( $_GET['wp_concatenate_scripts'] ) ) { // WPCS: csrf ok.
+		$concatenate_scripts = rest_sanitize_boolean( $_GET['wp_concatenate_scripts'] ); // WPCS: csrf ok, override ok.
+	}
+}