diff --git a/src/Microsoft.AspNetCore.Blazor.Browser.JS/Microsoft.AspNetCore.Blazor.Browser.JS.csproj b/src/Microsoft.AspNetCore.Blazor.Browser.JS/Microsoft.AspNetCore.Blazor.Browser.JS.csproj
index 71ad62f790..9b25255af7 100644
--- a/src/Microsoft.AspNetCore.Blazor.Browser.JS/Microsoft.AspNetCore.Blazor.Browser.JS.csproj
+++ b/src/Microsoft.AspNetCore.Blazor.Browser.JS/Microsoft.AspNetCore.Blazor.Browser.JS.csproj
@@ -24,11 +24,11 @@
     <Exec Command="npm install" />
   </Target>
 
-  <Target Name="RunWebpack" AfterTargets="ResolveReferences" Inputs="@(WebpackInputs)" Outputs="dist\blazor.js" DependsOnTargets="EnsureNpmRestored">
+  <Target Name="RunWebpack" AfterTargets="ResolveReferences" Inputs="@(WebpackInputs)" Outputs="dist\blazor.webassembly.js" DependsOnTargets="EnsureNpmRestored">
     <RemoveDir Directories="dist" />
     <Exec Command="npm run build" />
     <ItemGroup>
-      <EmbeddedResource Include="dist\blazor.js" LogicalName="blazor./blazor.js" />
+      <EmbeddedResource Include="dist\blazor.webassembly.js" LogicalName="blazor./blazor.webassembly.js" />
     </ItemGroup>
   </Target>
 </Project>
diff --git a/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Boot.ts b/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Boot.WebAssembly.ts
similarity index 73%
rename from src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Boot.ts
rename to src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Boot.WebAssembly.ts
index a483e8283d..364d896ed1 100644
--- a/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Boot.ts
+++ b/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Boot.WebAssembly.ts
@@ -1,9 +1,20 @@
 import '../../Microsoft.JSInterop/JavaScriptRuntime/src/Microsoft.JSInterop';
-import { platform } from './Environment';
-import { getAssemblyNameFromUrl } from './Platform/Url';
 import './GlobalExports';
+import * as Environment from './Environment';
+import { monoPlatform } from './Platform/Mono/MonoPlatform';
+import { getAssemblyNameFromUrl } from './Platform/Url';
+import { renderBatch } from './Rendering/Renderer';
+import { RenderBatch } from './Rendering/RenderBatch/RenderBatch';
+import { SharedMemoryRenderBatch } from './Rendering/RenderBatch/SharedMemoryRenderBatch';
+import { Pointer } from './Platform/Platform';
 
 async function boot() {
+  // Configure environment for execution under Mono WebAssembly with shared-memory rendering
+  const platform = Environment.setPlatform(monoPlatform);
+  window['Blazor']._internal.renderBatch = (browserRendererId: number, batchAddress: Pointer) => {
+    renderBatch(browserRendererId, new SharedMemoryRenderBatch(batchAddress));
+  };
+
   // Read startup config from the <script> element that's importing this file
   const allScriptElems = document.getElementsByTagName('script');
   const thisScriptElem = (document.currentScript || allScriptElems[allScriptElems.length - 1]) as HTMLScriptElement;
diff --git a/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Environment.ts b/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Environment.ts
index e3774e5f98..4b2ca96a30 100644
--- a/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Environment.ts
+++ b/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Environment.ts
@@ -1,6 +1,11 @@
-// Expose an export called 'platform' of the interface type 'Platform',
+// Expose an export called 'platform' of the interface type 'Platform',
 // so that consumers can be agnostic about which implementation they use.
 // Basic alternative to having an actual DI container.
 import { Platform } from './Platform/Platform';
-import { monoPlatform } from './Platform/Mono/MonoPlatform';
-export const platform: Platform = monoPlatform;
+
+export let platform: Platform;
+
+export function setPlatform(platformInstance: Platform) {
+  platform = platformInstance;
+  return platform;
+}
diff --git a/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/GlobalExports.ts b/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/GlobalExports.ts
index f5e8512200..90d8cf593d 100644
--- a/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/GlobalExports.ts
+++ b/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/GlobalExports.ts
@@ -1,22 +1,17 @@
 import { platform } from './Environment';
 import { navigateTo, internalFunctions as uriHelperInternalFunctions } from './Services/UriHelper';
 import { internalFunctions as httpInternalFunctions } from './Services/Http';
-import { attachRootComponentToElement, renderBatch } from './Rendering/Renderer';
+import { attachRootComponentToElement } from './Rendering/Renderer';
 import { Pointer } from './Platform/Platform';
-import { SharedMemoryRenderBatch } from './Rendering/RenderBatch/SharedMemoryRenderBatch';
 
-if (typeof window !== 'undefined') {
-  // When the library is loaded in a browser via a <script> element, make the
-  // following APIs available in global scope for invocation from JS
-  window['Blazor'] = {
-    platform,
-    navigateTo,
+// Make the following APIs available in global scope for invocation from JS
+window['Blazor'] = {
+  platform,
+  navigateTo,
 
-    _internal: {
-      attachRootComponentToElement,
-      renderBatch: (browserRendererId: number, batchAddress: Pointer) => renderBatch(browserRendererId, new SharedMemoryRenderBatch(batchAddress)),
-      http: httpInternalFunctions,
-      uriHelper: uriHelperInternalFunctions
-    }
-  };
-}
+  _internal: {
+    attachRootComponentToElement,
+    http: httpInternalFunctions,
+    uriHelper: uriHelperInternalFunctions
+  }
+};
diff --git a/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Rendering/BrowserRenderer.ts b/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Rendering/BrowserRenderer.ts
index c0b40db12c..09d13db7b9 100644
--- a/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Rendering/BrowserRenderer.ts
+++ b/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Rendering/BrowserRenderer.ts
@@ -320,13 +320,7 @@ function countDescendantFrames(batch: RenderBatch, frame: RenderTreeFrame): numb
   }
 }
 
-function raiseEvent(event: Event, browserRendererId: number, componentId: number, eventHandlerId: number, eventArgs: EventForDotNet<UIEventArgs>) {
-  if (!raiseEventMethod) {
-    raiseEventMethod = platform.findMethod(
-      'Microsoft.AspNetCore.Blazor.Browser', 'Microsoft.AspNetCore.Blazor.Browser.Rendering', 'BrowserRendererEventDispatcher', 'DispatchEvent'
-    );
-  }
-
+async function raiseEvent(event: Event, browserRendererId: number, componentId: number, eventHandlerId: number, eventArgs: EventForDotNet<UIEventArgs>) {
   const eventDescriptor = {
     browserRendererId,
     componentId,
@@ -334,8 +328,9 @@ function raiseEvent(event: Event, browserRendererId: number, componentId: number
     eventArgsType: eventArgs.type
   };
 
-  platform.callMethod(raiseEventMethod, null, [
-    platform.toDotNetString(JSON.stringify(eventDescriptor)),
-    platform.toDotNetString(JSON.stringify(eventArgs.data))
-  ]);
+  await DotNet.invokeMethodAsync(
+    'Microsoft.AspNetCore.Blazor.Browser',
+    'DispatchEvent',
+    eventDescriptor,
+    JSON.stringify(eventArgs.data));
 }
diff --git a/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Services/UriHelper.ts b/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Services/UriHelper.ts
index 67a42903d0..a427fc36a0 100644
--- a/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Services/UriHelper.ts
+++ b/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Services/UriHelper.ts
@@ -52,19 +52,12 @@ function performInternalNavigation(absoluteInternalHref: string) {
   handleInternalNavigation();
 }
 
-function handleInternalNavigation() {
-  if (!notifyLocationChangedMethod) {
-    notifyLocationChangedMethod = platform.findMethod(
-      'Microsoft.AspNetCore.Blazor.Browser',
-      'Microsoft.AspNetCore.Blazor.Browser.Services',
-      'BrowserUriHelper',
-      'NotifyLocationChanged'
-    );
-  }
-
-  platform.callMethod(notifyLocationChangedMethod, null, [
-    platform.toDotNetString(location.href)
-  ]);
+async function handleInternalNavigation() {
+  await DotNet.invokeMethodAsync(
+    'Microsoft.AspNetCore.Blazor.Browser',
+    'NotifyLocationChanged',
+    location.href
+  );
 }
 
 let testAnchor: HTMLAnchorElement;
diff --git a/src/Microsoft.AspNetCore.Blazor.Browser.JS/webpack.config.js b/src/Microsoft.AspNetCore.Blazor.Browser.JS/webpack.config.js
index 736867e48d..349dd45a41 100644
--- a/src/Microsoft.AspNetCore.Blazor.Browser.JS/webpack.config.js
+++ b/src/Microsoft.AspNetCore.Blazor.Browser.JS/webpack.config.js
@@ -7,6 +7,8 @@ module.exports = {
     module: {
         rules: [{ test: /\.ts?$/, loader: 'ts-loader' }]
     },
-    entry: { 'blazor': './src/Boot.ts' },
+    entry: {
+        'blazor.webassembly': './src/Boot.WebAssembly.ts',
+    },
     output: { path: path.join(__dirname, '/dist'), filename: '[name].js' }
 };
diff --git a/src/Microsoft.AspNetCore.Blazor.Browser/Rendering/BrowserRendererEventDispatcher.cs b/src/Microsoft.AspNetCore.Blazor.Browser/Rendering/BrowserRendererEventDispatcher.cs
index 03339e4ea1..f005c4f96b 100644
--- a/src/Microsoft.AspNetCore.Blazor.Browser/Rendering/BrowserRendererEventDispatcher.cs
+++ b/src/Microsoft.AspNetCore.Blazor.Browser/Rendering/BrowserRendererEventDispatcher.cs
@@ -10,15 +10,26 @@ namespace Microsoft.AspNetCore.Blazor.Browser.Rendering
     /// Provides mechanisms for dispatching events to components in a <see cref="BrowserRenderer"/>.
     /// This is marked 'internal' because it only gets invoked from JS code.
     /// </summary>
-    internal static class BrowserRendererEventDispatcher
+    public static class BrowserRendererEventDispatcher
     {
-        // We receive the information as JSON strings because of current interop limitations:
-        // - Can't pass unboxed value types from JS to .NET (yet all the IDs are ints)
-        // - Can't pass more than 4 args from JS to .NET
-        // This can be simplified in the future when the Mono WASM runtime is enhanced.
-        public static void DispatchEvent(string eventDescriptorJson, string eventArgsJson)
+        // TODO: Fix this for multi-user scenarios. Currently it doesn't stop people from
+        // triggering events for other people by passing an arbitrary browserRendererId.
+        //
+        // Preferred fix: Instead of storing the Renderer instances in a static dictionary
+        // store them within the context of a Circuit. Then we'll only look up the ones
+        // associated with the caller's circuit. This takes care of ensuring they are
+        // released when the circuit is closed too.
+        //
+        // More generally, we must move away from using statics for any per-user state
+        // now that we have multi-user scenarios.
+
+        /// <summary>
+        /// For framework use only.
+        /// </summary>
+        [JSInvokable(nameof(DispatchEvent))]
+        public static void DispatchEvent(
+            BrowserEventDescriptor eventDescriptor, string eventArgsJson)
         {
-            var eventDescriptor = Json.Deserialize<BrowserEventDescriptor>(eventDescriptorJson);
             var eventArgs = ParseEventArgsJson(eventDescriptor.EventArgsType, eventArgsJson);
             var browserRenderer = BrowserRendererRegistry.Find(eventDescriptor.BrowserRendererId);
             browserRenderer.DispatchBrowserEvent(
@@ -60,11 +71,29 @@ namespace Microsoft.AspNetCore.Blazor.Browser.Rendering
             }
         }
 
-        private class BrowserEventDescriptor
+        /// <summary>
+        /// For framework use only.
+        /// </summary>
+        public class BrowserEventDescriptor
         {
+            /// <summary>
+            /// For framework use only.
+            /// </summary>
             public int BrowserRendererId { get; set; }
+
+            /// <summary>
+            /// For framework use only.
+            /// </summary>
             public int ComponentId { get; set; }
+
+            /// <summary>
+            /// For framework use only.
+            /// </summary>
             public int EventHandlerId { get; set; }
+
+            /// <summary>
+            /// For framework use only.
+            /// </summary>
             public string EventArgsType { get; set; }
         }
     }
diff --git a/src/Microsoft.AspNetCore.Blazor.Browser/Services/BrowserUriHelper.cs b/src/Microsoft.AspNetCore.Blazor.Browser/Services/BrowserUriHelper.cs
index 7d952436ab..f06ee193ae 100644
--- a/src/Microsoft.AspNetCore.Blazor.Browser/Services/BrowserUriHelper.cs
+++ b/src/Microsoft.AspNetCore.Blazor.Browser/Services/BrowserUriHelper.cs
@@ -137,7 +137,11 @@ namespace Microsoft.AspNetCore.Blazor.Browser.Services
             }
         }
 
-        private static void NotifyLocationChanged(string newAbsoluteUri)
+        /// <summary>
+        /// For framework use only.
+        /// </summary>
+        [JSInvokable(nameof(NotifyLocationChanged))]
+        public static void NotifyLocationChanged(string newAbsoluteUri)
         {
             _cachedAbsoluteUri = newAbsoluteUri;
             _onLocationChanged?.Invoke(null, newAbsoluteUri);
diff --git a/src/Microsoft.AspNetCore.Blazor.Build/Core/IndexHtmlWriter.cs b/src/Microsoft.AspNetCore.Blazor.Build/Core/IndexHtmlWriter.cs
index e20eee54a0..535484c9fe 100644
--- a/src/Microsoft.AspNetCore.Blazor.Build/Core/IndexHtmlWriter.cs
+++ b/src/Microsoft.AspNetCore.Blazor.Build/Core/IndexHtmlWriter.cs
@@ -219,7 +219,7 @@ namespace Microsoft.AspNetCore.Blazor.Build
 
             var attributesDict = attributes.ToDictionary(x => x.Key, x => x.Value);
             attributesDict.Remove("type");
-            attributesDict["src"] = "_framework/blazor.js";
+            attributesDict["src"] = "_framework/blazor.webassembly.js";
             attributesDict["main"] = assemblyNameWithExtension;
             attributesDict["entrypoint"] = assemblyEntryPoint;
             attributesDict["references"] = referencesAttribute;
diff --git a/src/Microsoft.AspNetCore.Blazor.Build/Microsoft.AspNetCore.Blazor.Build.nuspec b/src/Microsoft.AspNetCore.Blazor.Build/Microsoft.AspNetCore.Blazor.Build.nuspec
index a12754287b..bbac5b9b57 100644
--- a/src/Microsoft.AspNetCore.Blazor.Build/Microsoft.AspNetCore.Blazor.Build.nuspec
+++ b/src/Microsoft.AspNetCore.Blazor.Build/Microsoft.AspNetCore.Blazor.Build.nuspec
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <package xmlns="http://schemas.microsoft.com/packaging/2012/06/nuspec.xsd">
   <metadata>
     <id>Microsoft.AspNetCore.Blazor.Build</id>
@@ -17,6 +17,6 @@
     <file src="$publishdir$\netcoreapp2.1\**\*" target="tools/" />
     <file src="..\mono\dist\optimized\**\*" target="tools\mono"  />
     <file src="..\mono\tools\binaries\illink\**\*.*" target="tools\illink" />
-    <file src="..\Microsoft.AspNetCore.Blazor.Browser.JS\dist\blazor.js" target="tools\blazor\blazor.js" />
+    <file src="..\Microsoft.AspNetCore.Blazor.Browser.JS\dist\blazor.*.js" target="tools\blazor" />
   </files>
 </package>
diff --git a/src/Microsoft.AspNetCore.Blazor.Build/ReferenceFromSource.props b/src/Microsoft.AspNetCore.Blazor.Build/ReferenceFromSource.props
index 10aed56fa6..30f69c8c21 100644
--- a/src/Microsoft.AspNetCore.Blazor.Build/ReferenceFromSource.props
+++ b/src/Microsoft.AspNetCore.Blazor.Build/ReferenceFromSource.props
@@ -16,7 +16,7 @@
     <MonoBaseClassLibraryFacadesPath>$(BlazorMonoRuntimeBasePath)dist/optimized/bcl/Facades/</MonoBaseClassLibraryFacadesPath>
     <MonoAsmjsRuntimePath>$(BlazorMonoRuntimeBasePath)dist/optimized/asmjs/</MonoAsmjsRuntimePath>
     <MonoWasmRuntimePath>$(BlazorMonoRuntimeBasePath)dist/optimized/wasm/</MonoWasmRuntimePath>
-    <BlazorJsPath>$(MSBuildThisFileDirectory)../Microsoft.AspNetCore.Blazor.Browser.JS/dist/blazor.js</BlazorJsPath>
+    <BlazorJsPath>$(MSBuildThisFileDirectory)../Microsoft.AspNetCore.Blazor.Browser.JS/dist/blazor.*.js</BlazorJsPath>
   </PropertyGroup>
 
   <Import Project="$(MSBuildThisFileDirectory)targets/All.props" />
diff --git a/src/Microsoft.AspNetCore.Blazor.Build/targets/Blazor.MonoRuntime.props b/src/Microsoft.AspNetCore.Blazor.Build/targets/Blazor.MonoRuntime.props
index cf76302e9f..610418d64a 100644
--- a/src/Microsoft.AspNetCore.Blazor.Build/targets/Blazor.MonoRuntime.props
+++ b/src/Microsoft.AspNetCore.Blazor.Build/targets/Blazor.MonoRuntime.props
@@ -6,7 +6,7 @@
     <MonoBaseClassLibraryFacadesPath>$(BlazorMonoRuntimeBasePath)tools/mono/bcl/Facades/</MonoBaseClassLibraryFacadesPath>
     <MonoAsmjsRuntimePath>$(BlazorMonoRuntimeBasePath)tools/mono/asmjs/</MonoAsmjsRuntimePath>
     <MonoWasmRuntimePath>$(BlazorMonoRuntimeBasePath)tools/mono/wasm/</MonoWasmRuntimePath>
-    <BlazorJsPath>$(BlazorMonoRuntimeBasePath)tools/blazor/blazor.js</BlazorJsPath>
+    <BlazorJsPath>$(BlazorMonoRuntimeBasePath)tools/blazor/blazor.*.js</BlazorJsPath>
   </PropertyGroup>
 
   <PropertyGroup Label="Blazor build outputs">
diff --git a/src/Microsoft.AspNetCore.Blazor.Server/Circuits/RenderBatchWriter.cs b/src/Microsoft.AspNetCore.Blazor.Server/Circuits/RenderBatchWriter.cs
new file mode 100644
index 0000000000..4554018f65
--- /dev/null
+++ b/src/Microsoft.AspNetCore.Blazor.Server/Circuits/RenderBatchWriter.cs
@@ -0,0 +1,249 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.Blazor.Rendering;
+using Microsoft.AspNetCore.Blazor.RenderTree;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Text;
+
+namespace Microsoft.AspNetCore.Blazor.Server.Circuits
+{
+    // TODO: We should consider *not* having this type of infrastructure in the .Server
+    // project, but instead in some new project called .Remote or similar, since it
+    // would also be used in Electron and possibly WebWorker cases.
+
+    /// <summary>
+    /// Provides a custom binary serializer for <see cref="RenderBatch"/> instances.
+    /// This is designed with both server-side and client-side perf in mind:
+    /// 
+    ///  * Array-like regions always have a fixed size per entry (even if some entry types
+    ///    don't require as much space as others) so the recipient can index directly.
+    ///  * The indices describing where field data starts, where each string value starts,
+    ///    etc., are written *after* that data, so when writing the data we don't have to
+    ///    compute the locations up front or seek back to an earlier point in the stream.
+    ///    The recipient can only process the data after reading it all into a buffer,
+    ///    so it's no disadvantage for the location info to be at the end.
+    ///  * We only serialize the data that the JS side will need. For example, we don't
+    ///    emit frame sequence numbers, or any representation of nonstring attribute
+    ///    values, or component instances, etc.
+    ///    
+    /// We don't have or need a .NET reader for this format. We only read it from JS code.
+    /// </summary>
+    internal class RenderBatchWriter : IDisposable
+    {
+        private readonly List<string> _strings;
+        private readonly BinaryWriter _binaryWriter;
+
+        public RenderBatchWriter(Stream output, bool leaveOpen)
+        {
+            _strings = new List<string>();
+            _binaryWriter = new BinaryWriter(output, Encoding.UTF8, leaveOpen);
+        }
+
+        public void Write(in RenderBatch renderBatch)
+        {
+            var updatedComponentsOffset = Write(renderBatch.UpdatedComponents);
+            var referenceFramesOffset = Write(renderBatch.ReferenceFrames);
+            var disposedComponentIdsOffset = Write(renderBatch.DisposedComponentIDs);
+            var disposedEventHandlerIdsOffset = Write(renderBatch.DisposedEventHandlerIDs);
+            var stringTableOffset = WriteStringTable();
+
+            _binaryWriter.Write(updatedComponentsOffset);
+            _binaryWriter.Write(referenceFramesOffset);
+            _binaryWriter.Write(disposedComponentIdsOffset);
+            _binaryWriter.Write(disposedEventHandlerIdsOffset);
+            _binaryWriter.Write(stringTableOffset);
+        }
+
+        int Write(in ArrayRange<RenderTreeDiff> diffs)
+        {
+            var count = diffs.Count;
+            var diffsIndexes = new int[count];
+            var array = diffs.Array;
+            var baseStream = _binaryWriter.BaseStream;
+            for (var i = 0; i < count; i++)
+            {
+                diffsIndexes[i] = (int)baseStream.Position;
+                Write(array[i]);
+            }
+
+            // Now write out the table of locations
+            var tableStartPos = (int)baseStream.Position;
+            _binaryWriter.Write(count);
+            for (var i = 0; i < count; i++)
+            {
+                _binaryWriter.Write(diffsIndexes[i]);
+            }
+
+            return tableStartPos;
+        }
+
+        void Write(in RenderTreeDiff diff)
+        {
+            _binaryWriter.Write(diff.ComponentId);
+
+            var edits = diff.Edits;
+            _binaryWriter.Write(edits.Count);
+
+            var editsArray = edits.Array;
+            var editsEndIndexExcl = edits.Offset + edits.Count;
+            for (var i = edits.Offset; i < editsEndIndexExcl; i++)
+            {
+                Write(editsArray[i]);
+            }
+        }
+
+        void Write(in RenderTreeEdit edit)
+        {
+            // We want all RenderTreeEdit outputs to be of the same length, so that
+            // the recipient can index into the array directly without walking it.
+            // So we output some value for all properties, even when not applicable
+            // for this specific RenderTreeEditType.
+            _binaryWriter.Write((int)edit.Type);
+            _binaryWriter.Write(edit.SiblingIndex);
+            _binaryWriter.Write(edit.ReferenceFrameIndex);
+            WriteString(edit.RemovedAttributeName);
+        }
+
+        int Write(in ArrayRange<RenderTreeFrame> frames)
+        {
+            var startPos = (int)_binaryWriter.BaseStream.Position;
+
+            var array = frames.Array;
+            var count = frames.Count;
+            _binaryWriter.Write(count);
+            for (var i = 0; i < count; i++)
+            {
+                Write(array[i]);
+            }
+
+            return startPos;
+        }
+
+        void Write(in RenderTreeFrame frame)
+        {
+            _binaryWriter.Write((int)frame.FrameType);
+
+            // We want each frame to take up the same number of bytes, so that the
+            // recipient can index into the array directly instead of having to
+            // walk through it.
+            // Since we can fit every frame type into 3 ints, use that as the
+            // common size. For smaller frames, we add padding to expand it to
+            // 12 bytes (i.e., 3 x 4-byte ints).
+            // The total size then for each frame is 16 bytes (frame type, then
+            // 3 other ints).
+            switch (frame.FrameType)
+            {
+                case RenderTreeFrameType.Attribute:
+                    WriteString(frame.AttributeName);
+                    WriteString(frame.AttributeValue as string);
+                    _binaryWriter.Write(frame.AttributeEventHandlerId);
+                    break;
+                case RenderTreeFrameType.Component:
+                    _binaryWriter.Write(frame.ComponentSubtreeLength);
+                    _binaryWriter.Write(frame.ComponentId);
+                    WritePadding(_binaryWriter, 4);
+                    break;
+                case RenderTreeFrameType.ComponentReferenceCapture:
+                    // The client doesn't need to know about these. But we still have
+                    // to include them in the array otherwise the ReferenceFrameIndex
+                    // values in the edits data would be wrong.
+                    WritePadding(_binaryWriter, 12);
+                    break;
+                case RenderTreeFrameType.Element:
+                    _binaryWriter.Write(frame.ElementSubtreeLength);
+                    WriteString(frame.ElementName);
+                    WritePadding(_binaryWriter, 4);
+                    break;
+                case RenderTreeFrameType.ElementReferenceCapture:
+                    _binaryWriter.Write(frame.ElementReferenceCaptureId);
+                    WritePadding(_binaryWriter, 8);
+                    break;
+                case RenderTreeFrameType.Region:
+                    _binaryWriter.Write(frame.RegionSubtreeLength);
+                    WritePadding(_binaryWriter, 8);
+                    break;
+                case RenderTreeFrameType.Text:
+                    WriteString(frame.TextContent);
+                    WritePadding(_binaryWriter, 8);
+                    break;
+                default:
+                    throw new ArgumentException($"Unsupported frame type: {frame.FrameType}");
+            }
+        }
+
+        int Write(in ArrayRange<int> numbers)
+        {
+            var startPos = (int)_binaryWriter.BaseStream.Position;
+            _binaryWriter.Write(numbers.Count);
+
+            var array = numbers.Array;
+            var count = numbers.Count;
+            for (var index = 0; index < count; index++)
+            {
+                _binaryWriter.Write(array[index]);
+            }
+
+            return startPos;
+        }
+
+        void WriteString(string value)
+        {
+            if (value == null)
+            {
+                _binaryWriter.Write(-1);
+            }
+            else
+            {
+                var stringIndex = _strings.Count;
+                _binaryWriter.Write(stringIndex);
+                _strings.Add(value);
+            }
+        }
+
+        int WriteStringTable()
+        {
+            // Capture the locations of each string
+            var stringsCount = _strings.Count;
+            var locations = new int[stringsCount];
+
+            for (var i = 0; i < stringsCount; i++)
+            {
+                var stringValue = _strings[i];
+                locations[i] = (int)_binaryWriter.BaseStream.Position;
+                _binaryWriter.Write(stringValue);
+            }
+
+            // Now write the locations
+            var locationsStartPos = (int)_binaryWriter.BaseStream.Position;
+            for (var i = 0; i < stringsCount; i++)
+            {
+                _binaryWriter.Write(locations[i]);
+            }
+
+            return locationsStartPos;
+        }
+
+        static void WritePadding(BinaryWriter writer, int numBytes)
+        {
+            while (numBytes >= 4)
+            {
+                writer.Write(0);
+                numBytes -= 4;
+            }
+
+            while (numBytes > 0)
+            {
+                writer.Write((byte)0);
+                numBytes--;
+            }
+        }
+
+        public void Dispose()
+        {
+            _binaryWriter.Dispose();
+        }
+    }
+}
diff --git a/src/Microsoft.AspNetCore.Blazor.Server/Microsoft.AspNetCore.Blazor.Server.csproj b/src/Microsoft.AspNetCore.Blazor.Server/Microsoft.AspNetCore.Blazor.Server.csproj
index ad810fad35..b47e52c0c6 100644
--- a/src/Microsoft.AspNetCore.Blazor.Server/Microsoft.AspNetCore.Blazor.Server.csproj
+++ b/src/Microsoft.AspNetCore.Blazor.Server/Microsoft.AspNetCore.Blazor.Server.csproj
@@ -13,4 +13,8 @@
     <PackageReference Include="Mono.Cecil" Version="0.10.0-beta7" />
   </ItemGroup>
 
+  <ItemGroup>
+    <ProjectReference Include="..\Microsoft.AspNetCore.Blazor\Microsoft.AspNetCore.Blazor.csproj" />
+  </ItemGroup>
+
 </Project>
diff --git a/src/Microsoft.AspNetCore.Blazor/Properties/AssemblyInfo.cs b/src/Microsoft.AspNetCore.Blazor/Properties/AssemblyInfo.cs
index fcbca4b037..536ccefae2 100644
--- a/src/Microsoft.AspNetCore.Blazor/Properties/AssemblyInfo.cs
+++ b/src/Microsoft.AspNetCore.Blazor/Properties/AssemblyInfo.cs
@@ -1,6 +1,7 @@
-using System.Runtime.CompilerServices;
+using System.Runtime.CompilerServices;
 
 [assembly: InternalsVisibleTo("Microsoft.AspNetCore.Blazor.Test")]
 [assembly: InternalsVisibleTo("Microsoft.AspNetCore.Blazor.Browser.Test")]
 [assembly: InternalsVisibleTo("Microsoft.AspNetCore.Blazor.Build.Test")]
 [assembly: InternalsVisibleTo("Microsoft.AspNetCore.Blazor.Performance")]
+[assembly: InternalsVisibleTo("Microsoft.AspNetCore.Blazor.Server.Test")]
diff --git a/test/Microsoft.AspNetCore.Blazor.Build.Test/IndexHtmlWriterTest.cs b/test/Microsoft.AspNetCore.Blazor.Build.Test/IndexHtmlWriterTest.cs
index e3ad517e12..d3cd45c9d8 100644
--- a/test/Microsoft.AspNetCore.Blazor.Build.Test/IndexHtmlWriterTest.cs
+++ b/test/Microsoft.AspNetCore.Blazor.Build.Test/IndexHtmlWriterTest.cs
@@ -1,4 +1,4 @@
-// Copyright (c) .NET Foundation. All rights reserved.
+// Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using AngleSharp.Parser.Html;
@@ -47,7 +47,7 @@ namespace Microsoft.AspNetCore.Blazor.Build.Test
             var linkElems = parsedHtml.Body.QuerySelectorAll("link");
             var scriptElem = scriptElems[0];
             Assert.False(scriptElem.HasChildNodes);
-            Assert.Equal("_framework/blazor.js", scriptElem.GetAttribute("src"));
+            Assert.Equal("_framework/blazor.webassembly.js", scriptElem.GetAttribute("src"));
             Assert.Equal("MyApp.Entrypoint.dll", scriptElem.GetAttribute("main"));
             Assert.Equal("MyNamespace.MyType::MyMethod", scriptElem.GetAttribute("entrypoint"));
             Assert.Equal("System.Abc.dll,MyApp.ClassLib.dll", scriptElem.GetAttribute("references"));
diff --git a/test/Microsoft.AspnetCore.Blazor.Server.Test/Circuits/CircuitSynchronizationContextTest.cs b/test/Microsoft.AspnetCore.Blazor.Server.Test/Circuits/CircuitSynchronizationContextTest.cs
index ff9352c9aa..74623f5507 100644
--- a/test/Microsoft.AspnetCore.Blazor.Server.Test/Circuits/CircuitSynchronizationContextTest.cs
+++ b/test/Microsoft.AspnetCore.Blazor.Server.Test/Circuits/CircuitSynchronizationContextTest.cs
@@ -9,7 +9,7 @@ using System.Threading.Tasks;
 using Microsoft.AspNetCore.Blazor.Server.Circuits;
 using Xunit;
 
-namespace Microsoft.AspnetCore.Blazor.Server
+namespace Microsoft.AspNetCore.Blazor.Server
 {
     public class CircuitSynchronizationContextTest
     {
diff --git a/test/Microsoft.AspnetCore.Blazor.Server.Test/Circuits/RenderBatchWriterTest.cs b/test/Microsoft.AspnetCore.Blazor.Server.Test/Circuits/RenderBatchWriterTest.cs
new file mode 100644
index 0000000000..370c6542b0
--- /dev/null
+++ b/test/Microsoft.AspnetCore.Blazor.Server.Test/Circuits/RenderBatchWriterTest.cs
@@ -0,0 +1,311 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.Blazor.Components;
+using Microsoft.AspNetCore.Blazor.Rendering;
+using Microsoft.AspNetCore.Blazor.RenderTree;
+using Microsoft.AspNetCore.Blazor.Server.Circuits;
+using System;
+using System.IO;
+using System.Text;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Blazor.Server
+{
+    public class RenderBatchWriterTest
+    {
+        static object NullStringMarker = new object();
+
+        [Fact]
+        public void CanSerializeEmptyRenderBatch()
+        {
+            // Arrange/Act
+            var bytes = Serialize(new RenderBatch());
+
+            // Assert
+            AssertBinaryContents(bytes, /* startIndex */ 0,
+                0,  // Length of UpdatedComponents
+                0,  // Length of ReferenceFrames
+                0,  // Length of DisposedComponentIds
+                0,  // Length of DisposedEventHandlerIds
+
+                0,  // Index of UpdatedComponents
+                4,  // Index of ReferenceFrames
+                8,  // Index of DisposedComponentIds
+                12, // Index of DisposedEventHandlerIds
+                16  // Index of Strings
+            );
+            Assert.Equal(36, bytes.Length); // No other data
+        }
+
+        [Fact]
+        public void CanIncludeDisposedComponentIds()
+        {
+            // Arrange/Act
+            var bytes = Serialize(new RenderBatch(
+                default,
+                default,
+                new ArrayRange<int>(new[] { 123, int.MaxValue, int.MinValue, 456 }, 3), // Only use first 3 to show that param is respected
+                default));
+
+            // Assert
+            AssertBinaryContents(bytes, /* startIndex */ 0,
+                0,  // Length of UpdatedComponents
+                0,  // Length of ReferenceFrames                
+                3, 123, int.MaxValue, int.MinValue, // DisposedComponentIds as length-prefixed array
+                0,  // Length of DisposedEventHandlerIds
+
+                0,  // Index of UpdatedComponents
+                4,  // Index of ReferenceFrames
+                8,  // Index of DisposedComponentIds
+                24, // Index of DisposedEventHandlerIds
+                28  // Index of strings
+            );
+            Assert.Equal(48, bytes.Length); // No other data
+        }
+
+        [Fact]
+        public void CanIncludeDisposedEventHandlerIds()
+        {
+            // Arrange/Act
+            var bytes = Serialize(new RenderBatch(
+                new ArrayRange<RenderTreeDiff>(),
+                new ArrayRange<RenderTreeFrame>(),
+                new ArrayRange<int>(),
+                new ArrayRange<int>(new[] { 123, int.MaxValue, int.MinValue, 456 }, 3) // Only use first 3 to show that param is respected
+                ));
+
+            // Assert
+            AssertBinaryContents(bytes, /* startIndex */ 0,
+                0,  // Length of UpdatedComponents
+                0,  // Length of ReferenceFrames
+                0,  // Length of DisposedComponentIds
+                3, 123, int.MaxValue, int.MinValue, // DisposedEventHandlerIds as length-prefixed array
+
+                0,  // Index of UpdatedComponents
+                4,  // Index of ReferenceFrames
+                8,  // Index of DisposedComponentIds
+                12, // Index of DisposedEventHandlerIds
+                28  // Index of strings
+            );
+            Assert.Equal(48, bytes.Length); // No other data
+        }
+
+        [Fact]
+        public void CanIncludeUpdatedComponentsWithEmptyEdits()
+        {
+            // Arrange/Act
+            var bytes = Serialize(new RenderBatch(
+                new ArrayRange<RenderTreeDiff>(new[]
+                {
+                    new RenderTreeDiff(123, default),
+                    new RenderTreeDiff(int.MaxValue, default),
+                }, 2),
+                default,
+                default,
+                default));
+
+            // Assert
+            AssertBinaryContents(bytes, /* startIndex */ 0,
+                // UpdatedComponents[0]
+                123, // ComponentId
+                0,   // Edits length
+
+                // UpdatedComponents[1]
+                int.MaxValue, // ComponentId
+                0,   // Edits length
+
+                2,   // Length of UpdatedComponents
+                0,   // Index of UpdatedComponents[0]
+                8,   // Index of UpdatedComponents[1]
+                
+                0,   // Length of ReferenceFrames
+                0,   // Length of DisposedComponentIds
+                0,   // Length of DisposedEventHandlerIds
+
+                16,  // Index of UpdatedComponents
+                28,  // Index of ReferenceFrames
+                32,  // Index of DisposedComponentIds
+                36,  // Index of DisposedEventHandlerIds
+                40   // Index of strings
+            );
+            Assert.Equal(60, bytes.Length); // No other data
+        }
+
+        [Fact]
+        public void CanIncludeEdits()
+        {
+            // Arrange/Act
+            var edits = new[]
+            {
+                default, // Skipped (because offset=1 below)
+                RenderTreeEdit.PrependFrame(456, 789),
+                RenderTreeEdit.RemoveFrame(101),
+                RenderTreeEdit.SetAttribute(102, 103),
+                RenderTreeEdit.RemoveAttribute(104, "Some removed attribute"),
+                RenderTreeEdit.UpdateText(105, 106),
+                RenderTreeEdit.StepIn(107),
+                RenderTreeEdit.StepOut(),
+            };
+            var bytes = Serialize(new RenderBatch(
+                new ArrayRange<RenderTreeDiff>(new[]
+                {
+                    new RenderTreeDiff(123, new ArraySegment<RenderTreeEdit>(
+                        edits, 1, edits.Length - 1)) // Skip first to show offset is respected
+                }, 1),
+                default,
+                default,
+                default));
+
+            // Assert
+            var diffsStartIndex = ReadInt(bytes, bytes.Length - 20);
+            AssertBinaryContents(bytes, diffsStartIndex,
+                1,  // Number of diffs
+                0); // Index of diffs[0]
+
+            AssertBinaryContents(bytes, 0,
+                123, // Component ID for diff 0
+                7,  // diff[0].Edits.Count
+                RenderTreeEditType.PrependFrame, 456, 789, NullStringMarker,
+                RenderTreeEditType.RemoveFrame, 101, 0, NullStringMarker,
+                RenderTreeEditType.SetAttribute, 102, 103, NullStringMarker,
+                RenderTreeEditType.RemoveAttribute, 104, 0, "Some removed attribute",
+                RenderTreeEditType.UpdateText, 105, 106, NullStringMarker,
+                RenderTreeEditType.StepIn, 107, 0, NullStringMarker,
+                RenderTreeEditType.StepOut, 0, 0, NullStringMarker
+            );
+        }
+
+        [Fact]
+        public void CanIncludeReferenceFrames()
+        {
+            // Arrange/Act
+            var bytes = Serialize(new RenderBatch(
+                default,
+                new ArrayRange<RenderTreeFrame>(new[] {
+                    RenderTreeFrame.Attribute(123, "Attribute with string value", "String value"),
+                    RenderTreeFrame.Attribute(124, "Attribute with nonstring value", 1),
+                    RenderTreeFrame.Attribute(125, "Attribute with delegate value", new Action(() => { }))
+                        .WithAttributeEventHandlerId(789),
+                    RenderTreeFrame.ChildComponent(126, typeof(object))
+                        .WithComponentSubtreeLength(5678)
+                        .WithComponentInstance(2000, new FakeComponent()),
+                    RenderTreeFrame.ComponentReferenceCapture(127, value => { }, 1001),
+                    RenderTreeFrame.Element(128, "Some element")
+                        .WithElementSubtreeLength(1234),
+                    RenderTreeFrame.ElementReferenceCapture(129, value => { })
+                        .WithElementReferenceCaptureId(12121),
+                    RenderTreeFrame.Region(130)
+                        .WithRegionSubtreeLength(1234),
+                    RenderTreeFrame.Text(131, "Some text"),
+                }, 9),
+                default,
+                default));
+
+            // Assert
+            var referenceFramesStartIndex = ReadInt(bytes, bytes.Length - 16);
+            AssertBinaryContents(bytes, referenceFramesStartIndex,
+                9, // Number of frames
+                RenderTreeFrameType.Attribute, "Attribute with string value", "String value", 0,
+                RenderTreeFrameType.Attribute, "Attribute with nonstring value", NullStringMarker, 0,
+                RenderTreeFrameType.Attribute, "Attribute with delegate value", NullStringMarker, 789,
+                RenderTreeFrameType.Component, 5678, 2000, 0,
+                RenderTreeFrameType.ComponentReferenceCapture, 0, 0, 0,
+                RenderTreeFrameType.Element, 1234, "Some element", 0,
+                RenderTreeFrameType.ElementReferenceCapture, 12121, 0, 0,
+                RenderTreeFrameType.Region, 1234, 0, 0,
+                RenderTreeFrameType.Text, "Some text", 0, 0
+            );
+        }
+
+        private Span<byte> Serialize(RenderBatch renderBatch)
+        {
+            using (var ms = new MemoryStream())
+            using (var writer = new RenderBatchWriter(ms, leaveOpen: false))
+            {
+                writer.Write(renderBatch);
+                return new Span<byte>(ms.ToArray(), 0, (int)ms.Length);
+            }
+        }
+
+        static void AssertBinaryContents(Span<byte> data, int startIndex, params object[] entries)
+        {
+            var bytes = data.ToArray();
+
+            // The string table position is given by the final int
+            var stringTableStartPosition = BitConverter.ToInt32(bytes, bytes.Length - 4);
+
+            using (var ms = new MemoryStream(bytes))
+            using (var reader = new BinaryReader(ms))
+            {
+                ms.Seek(startIndex, SeekOrigin.Begin);
+
+                foreach (var expectedEntryIterationVar in entries)
+                {
+                    // Assume enums are represented as ints
+                    var expectedEntry = expectedEntryIterationVar.GetType().IsEnum
+                        ? (int)expectedEntryIterationVar
+                        : expectedEntryIterationVar;
+
+                    if (expectedEntry is int expectedInt)
+                    {
+                        Assert.Equal(expectedInt, reader.ReadInt32());
+                    }
+                    else if (expectedEntry is string || expectedEntry == NullStringMarker)
+                    {
+                        // For strings, we have to look up the value in the table of strings
+                        // that appears at the end of the serialized data
+                        var indexIntoStringTable = reader.ReadInt32();
+                        var expectedString = expectedEntry as string;
+                        if (expectedString == null)
+                        {
+                            Assert.Equal(-1, indexIntoStringTable);
+                        }
+                        else
+                        {
+                            // The string table entries are all length-prefixed UTF8 blobs
+                            var tableEntryPos = BitConverter.ToInt32(bytes, stringTableStartPosition + 4 * indexIntoStringTable);
+                            var length = (int)ReadUnsignedLEB128(bytes, tableEntryPos, out var numLEB128Bytes);
+                            var value = Encoding.UTF8.GetString(bytes, tableEntryPos + numLEB128Bytes, length);
+                            Assert.Equal(expectedString, value);
+                        }
+                    }
+                    else
+                    {
+                        throw new InvalidOperationException($"Unsupported type: {expectedEntry.GetType().FullName}");
+                    }
+                }
+            }
+        }
+
+        static int ReadInt(Span<byte> bytes, int startOffset)
+            => BitConverter.ToInt32(bytes.Slice(startOffset, 4).ToArray(), 0);
+
+        public static uint ReadUnsignedLEB128(byte[] bytes, int startOffset, out int numBytesRead)
+        {
+            var result = (uint)0;
+            var shift = 0;
+            var currentByte = (byte)128;
+            numBytesRead = 0;
+
+            for (var count = 0; count < 4 && currentByte >= 128; count++)
+            {
+                currentByte = bytes[startOffset + count];
+                result += (uint)(currentByte & 0x7f) << shift;
+                shift += 7;
+                numBytesRead++;
+            }
+            
+            return result;
+        }
+
+        class FakeComponent : IComponent
+        {
+            public void Init(RenderHandle renderHandle)
+                => throw new NotImplementedException();
+
+            public void SetParameters(ParameterCollection parameters)
+                => throw new NotImplementedException();
+        }
+    }
+}
diff --git a/test/testapps/BasicTestApp/Program.cs b/test/testapps/BasicTestApp/Program.cs
index 054a9cf0a3..ab5fa9ba07 100644
--- a/test/testapps/BasicTestApp/Program.cs
+++ b/test/testapps/BasicTestApp/Program.cs
@@ -22,6 +22,7 @@ namespace BasicTestApp
             JSRuntime.Current.InvokeAsync<object>("testReady");
         }
 
+        [JSInvokable(nameof(MountTestComponent))]
         public static void MountTestComponent(string componentTypeName)
         {
             var componentType = Type.GetType(componentTypeName);
diff --git a/test/testapps/BasicTestApp/wwwroot/index.html b/test/testapps/BasicTestApp/wwwroot/index.html
index 005b8d277b..576ba709b1 100644
--- a/test/testapps/BasicTestApp/wwwroot/index.html
+++ b/test/testapps/BasicTestApp/wwwroot/index.html
@@ -62,8 +62,7 @@
     // The Xunit test code calls this when setting up tests for specific components
     function mountTestComponent(typeName) {
       document.getElementById('source-info').innerHTML = '<code><tt>' + typeName.replace(/\./g, '/') + '.cshtml</code></strong>';
-      var method = Blazor.platform.findMethod('BasicTestApp', 'BasicTestApp', 'Program', 'MountTestComponent');
-      Blazor.platform.callMethod(method, null, [Blazor.platform.toDotNetString(typeName)]);
+      DotNet.invokeMethodAsync('BasicTestApp', 'MountTestComponent', typeName);
     }
 
     // Used by ElementRefComponent