@@ -122,6 +122,19 @@ Tip: In the [API reference section](api) of this doc site, deprecated APIs are i
 | --- | ----------- | --------------------- | ----- |
 | [`preserveQueryParams`](api/router/NavigationExtras#preserveQueryParams) | [`queryParamsHandling`](api/router/NavigationExtras#queryParamsHandling) | v4 | none |
 
+{@a platform-webworker}
+### @angular/platform-webworker
+
+| API | Replacement | Deprecation announced | Notes |
+| --- | ----------- | --------------------- | ----- |
+| [All entry points](api/platform-webworker) | none | v8 | See [platform-webworker](#webworker-apps). |
+
+{@a platform-webworker-dynamic}
+### @angular/platform-webworker-dynamic
+
+| API | Replacement | Deprecation announced | Notes |
+| --- | ----------- | --------------------- | ----- |
+| [All entry points](api/platform-webworker-dynamic) | none | v8 | See [platform-webworker](#webworker-apps). |
 
 {@a upgrade}
 ### @angular/upgrade
@@ -380,6 +393,21 @@ Instead, use web workers primarily for offloading CPU intensive, but functionall
 
 
 
+{@a webworker-apps}
+### platform-webworker Angular applications
+
+
+platform-webworker has been around since the initial release of Angular version 2. It began as an experiment to leverage Angular's rendering architecture and try something different: to run an entire web application in a web worker.
+
+We've learned a lot from this experiment, and have come to the conclusion that pushing entire applications to run in a web worker is not a recipe for success for most applications. This is due to a number of unresolved issues, including:
+
+* Poor or non-existent support for web worker APIs in web crawlers/indexers.
+* Poor support in build and bundling tooling.
+
+As a result, as of Angular version 8, we are deprecating the `platform-webworker` APIs in Angular. This consists of both NPM packages, `@angular/platform-webworker` and `@angular/platform-webworker-dynamic`.
+
+Going forward, we will focus our efforts related to web workers around their primary use case of offloading CPU-intensive but not critical work.
+
 {@a removed}
 ## Removed APIs
 
 
@@ -16,6 +16,7 @@ export {VERSION} from './version';
 
 /**
  * @publicApi
+ * @deprecated platform-webworker is deprecated in Angular and will be removed in version 10
  */
 export const platformWorkerAppDynamic =
     createPlatformFactory(platformCoreDynamic, 'workerAppDynamic', [
 
@@ -16,5 +16,6 @@ import {Version} from '@angular/core';
 
 /**
  * @publicApi
+ * @deprecated platform-webworker is deprecated in Angular and will be removed in version 10
  */
 export const VERSION = new Version('0.0.0-PLACEHOLDER');
@@ -24,6 +24,7 @@ export {platformWorkerUi} from './worker_render';
  * Bootstraps the worker ui.
  *
  * @publicApi
+ * @deprecated platform-webworker is deprecated in Angular and will be removed in version 10
  */
 export function bootstrapWorkerUi(
     workerScriptUri: string, customProviders: StaticProvider[] = []): Promise<PlatformRef> {
 
@@ -16,5 +16,6 @@ import {Version} from '@angular/core';
 
 /**
  * @publicApi
+ * @deprecated platform-webworker is deprecated in Angular and will be removed in version 10
  */
 export const VERSION = new Version('0.0.0-PLACEHOLDER');
@@ -12,6 +12,7 @@ import {Serializer, SerializerTypes} from './serializer';
 
 /**
  * @publicApi
+ * @deprecated platform-webworker is deprecated in Angular and will be removed in version 10
  */
 @Injectable()
 export class ClientMessageBrokerFactory {
@@ -39,6 +40,7 @@ interface PromiseCompleter {
 
 /**
  * @publicApi
+ * @deprecated platform-webworker is deprecated in Angular and will be removed in version 10
  */
 export class ClientMessageBroker {
   private _pending = new Map<string, PromiseCompleter>();
 
@@ -17,6 +17,7 @@ import {EventEmitter, NgZone} from '@angular/core';
  * by the corresponding MessageBusSource.
  *
  * @publicApi
+ * @deprecated platform-webworker is deprecated in Angular and will be removed in version 10
  */
 export abstract class MessageBus implements MessageBusSource, MessageBusSink {
   /**
 
@@ -12,6 +12,7 @@ import {RenderStore} from './render_store';
 
 /**
  * @publicApi
+ * @deprecated platform-webworker is deprecated in Angular and will be removed in version 10
  */
 export const enum SerializerTypes {
   // RendererType2
 
@@ -13,6 +13,7 @@ import {Serializer, SerializerTypes} from '../shared/serializer';
 
 /**
  * @publicApi
+ * @deprecated platform-webworker is deprecated in Angular and will be removed in version 10
  */
 @Injectable()
 export class ServiceMessageBrokerFactory {
@@ -40,6 +41,7 @@ export class ServiceMessageBrokerFactory {
  * If that method returns a promise, the UIMessageBroker returns the result to the worker.
  *
  * @publicApi
+ * @deprecated platform-webworker is deprecated in Angular and will be removed in version 10
  */
 export class ServiceMessageBroker {
   private _sink: EventEmitter<any>;
@@ -91,6 +93,7 @@ export class ServiceMessageBroker {
 
 /**
  * @publicApi
+ * @deprecated platform-webworker is deprecated in Angular and will be removed in version 10
  */
 export interface ReceivedMessage {
   method: string;
 
@@ -22,6 +22,7 @@ import {MessageBasedPlatformLocation} from './platform_location';
  * A list of {@link Provider}s. To use the router in a Worker enabled application you must
  * include these providers when setting up the render thread.
  * @publicApi
+ * @deprecated platform-webworker is deprecated in Angular and will be removed in version 10
  */
 export const WORKER_UI_LOCATION_PROVIDERS = <StaticProvider[]>[
   {provide: MessageBasedPlatformLocation, deps: [ServiceMessageBrokerFactory,
Original file line number	Diff line number	Diff line change
`@@ -24,6 +24,7 @@ export {platformWorkerUi} from './worker_render';`
`24`	`24`	`* Bootstraps the worker ui.`
`25`	`25`	`*`
`26`	`26`	`* @publicApi`
	`27`	`+ * @deprecated platform-webworker is deprecated in Angular and will be removed in version 10`
`27`	`28`	`*/`
`28`	`29`	`export function bootstrapWorkerUi(`
`29`	`30`	`workerScriptUri: string, customProviders: StaticProvider[] = []): Promise<PlatformRef> {`
Original file line number	Diff line number	Diff line change
`@@ -17,6 +17,7 @@ import {EventEmitter, NgZone} from '@angular/core';`
`17`	`17`	`* by the corresponding MessageBusSource.`
`18`	`18`	`*`
`19`	`19`	`* @publicApi`
	`20`	`+ * @deprecated platform-webworker is deprecated in Angular and will be removed in version 10`
`20`	`21`	`*/`
`21`	`22`	`export abstract class MessageBus implements MessageBusSource, MessageBusSink {`
`22`	`23`	`/**`