diff --git a/Razor.sln b/Razor.sln
index 8ec09b65d3e..b0a9658f85e 100644
--- a/Razor.sln
+++ b/Razor.sln
@@ -65,6 +65,7 @@ EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "build", "build", "{4CAC99E0-6ECE-4264-96C3-AF4EEE7BC9D1}"
 	ProjectSection(SolutionItems) = preProject
 		.editorconfig = .editorconfig
+		NuGet.config = NuGet.config
 		SpellingExclusions.dic = SpellingExclusions.dic
 		eng\Versions.props = eng\Versions.props
 	EndProjectSection
diff --git a/eng/Version.Details.xml b/eng/Version.Details.xml
index 36f8f312e89..34844be67a9 100644
--- a/eng/Version.Details.xml
+++ b/eng/Version.Details.xml
@@ -10,78 +10,78 @@
       <Sha>2a008ae4f42c0db384db5a4864752b2ff52d720b</Sha>
       <SourceBuild RepoName="source-build-reference-packages" ManagedOnly="true" />
     </Dependency>
-    <Dependency Name="Microsoft.Net.Compilers.Toolset" Version="4.9.0-1.23530.5">
+    <Dependency Name="Microsoft.Net.Compilers.Toolset" Version="4.9.0-3.23613.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>5a41731d6717929d437137c1d0373135b5af88a0</Sha>
+      <Sha>93677976e310e7f910f289e962566485cbabf8f3</Sha>
       <SourceBuild RepoName="roslyn" ManagedOnly="true" />
     </Dependency>
-    <Dependency Name="Microsoft.CommonLanguageServerProtocol.Framework" Version="4.9.0-1.23530.5">
+    <Dependency Name="Microsoft.CommonLanguageServerProtocol.Framework" Version="4.9.0-3.23613.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>5a41731d6717929d437137c1d0373135b5af88a0</Sha>
+      <Sha>93677976e310e7f910f289e962566485cbabf8f3</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.CodeAnalysis.ExternalAccess.Razor" Version="4.9.0-1.23530.5">
+    <Dependency Name="Microsoft.CodeAnalysis.ExternalAccess.Razor" Version="4.9.0-3.23613.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>5a41731d6717929d437137c1d0373135b5af88a0</Sha>
+      <Sha>93677976e310e7f910f289e962566485cbabf8f3</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.CodeAnalysis.Common" Version="4.9.0-1.23530.5">
+    <Dependency Name="Microsoft.CodeAnalysis.Common" Version="4.9.0-3.23613.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>5a41731d6717929d437137c1d0373135b5af88a0</Sha>
+      <Sha>93677976e310e7f910f289e962566485cbabf8f3</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.CodeAnalysis.CSharp" Version="4.9.0-1.23530.5">
+    <Dependency Name="Microsoft.CodeAnalysis.CSharp" Version="4.9.0-3.23613.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>5a41731d6717929d437137c1d0373135b5af88a0</Sha>
+      <Sha>93677976e310e7f910f289e962566485cbabf8f3</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.CodeAnalysis.CSharp.EditorFeatures" Version="4.9.0-1.23530.5">
+    <Dependency Name="Microsoft.CodeAnalysis.CSharp.EditorFeatures" Version="4.9.0-3.23613.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>5a41731d6717929d437137c1d0373135b5af88a0</Sha>
+      <Sha>93677976e310e7f910f289e962566485cbabf8f3</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.CodeAnalysis.CSharp.Features" Version="4.9.0-1.23530.5">
+    <Dependency Name="Microsoft.CodeAnalysis.CSharp.Features" Version="4.9.0-3.23613.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>5a41731d6717929d437137c1d0373135b5af88a0</Sha>
+      <Sha>93677976e310e7f910f289e962566485cbabf8f3</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.9.0-1.23530.5">
+    <Dependency Name="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.9.0-3.23613.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>5a41731d6717929d437137c1d0373135b5af88a0</Sha>
+      <Sha>93677976e310e7f910f289e962566485cbabf8f3</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.CodeAnalysis.EditorFeatures" Version="4.9.0-1.23530.5">
+    <Dependency Name="Microsoft.CodeAnalysis.EditorFeatures" Version="4.9.0-3.23613.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>5a41731d6717929d437137c1d0373135b5af88a0</Sha>
+      <Sha>93677976e310e7f910f289e962566485cbabf8f3</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.CodeAnalysis.EditorFeatures.Common" Version="4.9.0-1.23530.5">
+    <Dependency Name="Microsoft.CodeAnalysis.EditorFeatures.Common" Version="4.9.0-3.23613.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>5a41731d6717929d437137c1d0373135b5af88a0</Sha>
+      <Sha>93677976e310e7f910f289e962566485cbabf8f3</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.CodeAnalysis.EditorFeatures.Text" Version="4.9.0-1.23530.5">
+    <Dependency Name="Microsoft.CodeAnalysis.EditorFeatures.Text" Version="4.9.0-3.23613.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>5a41731d6717929d437137c1d0373135b5af88a0</Sha>
+      <Sha>93677976e310e7f910f289e962566485cbabf8f3</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.CodeAnalysis.EditorFeatures.Wpf" Version="4.9.0-1.23530.5">
+    <Dependency Name="Microsoft.CodeAnalysis.EditorFeatures.Wpf" Version="4.9.0-3.23613.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>5a41731d6717929d437137c1d0373135b5af88a0</Sha>
+      <Sha>93677976e310e7f910f289e962566485cbabf8f3</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.CodeAnalysis.Remote.ServiceHub" Version="4.9.0-1.23530.5">
+    <Dependency Name="Microsoft.CodeAnalysis.Remote.ServiceHub" Version="4.9.0-3.23613.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>5a41731d6717929d437137c1d0373135b5af88a0</Sha>
+      <Sha>93677976e310e7f910f289e962566485cbabf8f3</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.CodeAnalysis.VisualBasic.Workspaces" Version="4.9.0-1.23530.5">
+    <Dependency Name="Microsoft.CodeAnalysis.VisualBasic.Workspaces" Version="4.9.0-3.23613.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>5a41731d6717929d437137c1d0373135b5af88a0</Sha>
+      <Sha>93677976e310e7f910f289e962566485cbabf8f3</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.CodeAnalysis.Workspaces.Common" Version="4.9.0-1.23530.5">
+    <Dependency Name="Microsoft.CodeAnalysis.Workspaces.Common" Version="4.9.0-3.23613.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>5a41731d6717929d437137c1d0373135b5af88a0</Sha>
+      <Sha>93677976e310e7f910f289e962566485cbabf8f3</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.CodeAnalysis.Workspaces.MSBuild" Version="4.9.0-1.23530.5">
+    <Dependency Name="Microsoft.CodeAnalysis.Workspaces.MSBuild" Version="4.9.0-3.23613.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>5a41731d6717929d437137c1d0373135b5af88a0</Sha>
+      <Sha>93677976e310e7f910f289e962566485cbabf8f3</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.VisualStudio.LanguageServices" Version="4.9.0-1.23530.5">
+    <Dependency Name="Microsoft.VisualStudio.LanguageServices" Version="4.9.0-3.23613.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>5a41731d6717929d437137c1d0373135b5af88a0</Sha>
+      <Sha>93677976e310e7f910f289e962566485cbabf8f3</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.CodeAnalysis.Test.Utilities" Version="4.9.0-1.23530.5">
+    <Dependency Name="Microsoft.CodeAnalysis.Test.Utilities" Version="4.9.0-3.23613.4">
       <Uri>https://github.com/dotnet/roslyn</Uri>
-      <Sha>5a41731d6717929d437137c1d0373135b5af88a0</Sha>
+      <Sha>93677976e310e7f910f289e962566485cbabf8f3</Sha>
     </Dependency>
   </ProductDependencies>
   <ToolsetDependencies>
diff --git a/eng/Versions.props b/eng/Versions.props
index dba5bdf3a14..a26cdea7b16 100644
--- a/eng/Versions.props
+++ b/eng/Versions.props
@@ -52,24 +52,24 @@
     <MicrosoftNETCoreBrowserDebugHostTransportPackageVersion>6.0.2-servicing.22064.6</MicrosoftNETCoreBrowserDebugHostTransportPackageVersion>
     <MicrosoftNETCorePlatformsPackageVersion>6.0.1</MicrosoftNETCorePlatformsPackageVersion>
     <MicrosoftSourceBuildIntermediatesourcebuildreferencepackagesPackageVersion>9.0.0-alpha.1.23627.2</MicrosoftSourceBuildIntermediatesourcebuildreferencepackagesPackageVersion>
-    <MicrosoftNetCompilersToolsetPackageVersion>4.9.0-1.23530.5</MicrosoftNetCompilersToolsetPackageVersion>
-    <MicrosoftCommonLanguageServerProtocolFrameworkPackageVersion>4.9.0-1.23530.5</MicrosoftCommonLanguageServerProtocolFrameworkPackageVersion>
-    <MicrosoftCodeAnalysisExternalAccessRazorPackageVersion>4.9.0-1.23530.5</MicrosoftCodeAnalysisExternalAccessRazorPackageVersion>
-    <MicrosoftCodeAnalysisCommonPackageVersion>4.9.0-1.23530.5</MicrosoftCodeAnalysisCommonPackageVersion>
-    <MicrosoftCodeAnalysisCSharpPackageVersion>4.9.0-1.23530.5</MicrosoftCodeAnalysisCSharpPackageVersion>
-    <MicrosoftCodeAnalysisCSharpEditorFeaturesPackageVersion>4.9.0-1.23530.5</MicrosoftCodeAnalysisCSharpEditorFeaturesPackageVersion>
-    <MicrosoftCodeAnalysisCSharpFeaturesPackageVersion>4.9.0-1.23530.5</MicrosoftCodeAnalysisCSharpFeaturesPackageVersion>
-    <MicrosoftCodeAnalysisCSharpWorkspacesPackageVersion>4.9.0-1.23530.5</MicrosoftCodeAnalysisCSharpWorkspacesPackageVersion>
-    <MicrosoftCodeAnalysisEditorFeaturesPackageVersion>4.9.0-1.23530.5</MicrosoftCodeAnalysisEditorFeaturesPackageVersion>
-    <MicrosoftCodeAnalysisEditorFeaturesCommonPackageVersion>4.9.0-1.23530.5</MicrosoftCodeAnalysisEditorFeaturesCommonPackageVersion>
-    <MicrosoftCodeAnalysisEditorFeaturesTextPackageVersion>4.9.0-1.23530.5</MicrosoftCodeAnalysisEditorFeaturesTextPackageVersion>
-    <MicrosoftCodeAnalysisEditorFeaturesWpfPackageVersion>4.9.0-1.23530.5</MicrosoftCodeAnalysisEditorFeaturesWpfPackageVersion>
-    <MicrosoftCodeAnalysisRemoteServiceHubPackageVersion>4.9.0-1.23530.5</MicrosoftCodeAnalysisRemoteServiceHubPackageVersion>
-    <MicrosoftCodeAnalysisTestUtilitiesPackageVersion>4.9.0-1.23530.5</MicrosoftCodeAnalysisTestUtilitiesPackageVersion>
-    <MicrosoftCodeAnalysisVisualBasicWorkspacesPackageVersion>4.9.0-1.23530.5</MicrosoftCodeAnalysisVisualBasicWorkspacesPackageVersion>
-    <MicrosoftCodeAnalysisWorkspacesCommonPackageVersion>4.9.0-1.23530.5</MicrosoftCodeAnalysisWorkspacesCommonPackageVersion>
-    <MicrosoftCodeAnalysisWorkspacesMSBuildPackageVersion>4.9.0-1.23530.5</MicrosoftCodeAnalysisWorkspacesMSBuildPackageVersion>
-    <MicrosoftVisualStudioLanguageServicesPackageVersion>4.9.0-1.23530.5</MicrosoftVisualStudioLanguageServicesPackageVersion>
+    <MicrosoftNetCompilersToolsetPackageVersion>4.9.0-3.23613.4</MicrosoftNetCompilersToolsetPackageVersion>
+    <MicrosoftCommonLanguageServerProtocolFrameworkPackageVersion>4.9.0-3.23613.4</MicrosoftCommonLanguageServerProtocolFrameworkPackageVersion>
+    <MicrosoftCodeAnalysisExternalAccessRazorPackageVersion>4.9.0-3.23613.4</MicrosoftCodeAnalysisExternalAccessRazorPackageVersion>
+    <MicrosoftCodeAnalysisCommonPackageVersion>4.9.0-3.23613.4</MicrosoftCodeAnalysisCommonPackageVersion>
+    <MicrosoftCodeAnalysisCSharpPackageVersion>4.9.0-3.23613.4</MicrosoftCodeAnalysisCSharpPackageVersion>
+    <MicrosoftCodeAnalysisCSharpEditorFeaturesPackageVersion>4.9.0-3.23613.4</MicrosoftCodeAnalysisCSharpEditorFeaturesPackageVersion>
+    <MicrosoftCodeAnalysisCSharpFeaturesPackageVersion>4.9.0-3.23613.4</MicrosoftCodeAnalysisCSharpFeaturesPackageVersion>
+    <MicrosoftCodeAnalysisCSharpWorkspacesPackageVersion>4.9.0-3.23613.4</MicrosoftCodeAnalysisCSharpWorkspacesPackageVersion>
+    <MicrosoftCodeAnalysisEditorFeaturesPackageVersion>4.9.0-3.23613.4</MicrosoftCodeAnalysisEditorFeaturesPackageVersion>
+    <MicrosoftCodeAnalysisEditorFeaturesCommonPackageVersion>4.9.0-3.23613.4</MicrosoftCodeAnalysisEditorFeaturesCommonPackageVersion>
+    <MicrosoftCodeAnalysisEditorFeaturesTextPackageVersion>4.9.0-3.23613.4</MicrosoftCodeAnalysisEditorFeaturesTextPackageVersion>
+    <MicrosoftCodeAnalysisEditorFeaturesWpfPackageVersion>4.9.0-3.23613.4</MicrosoftCodeAnalysisEditorFeaturesWpfPackageVersion>
+    <MicrosoftCodeAnalysisRemoteServiceHubPackageVersion>4.9.0-3.23613.4</MicrosoftCodeAnalysisRemoteServiceHubPackageVersion>
+    <MicrosoftCodeAnalysisTestUtilitiesPackageVersion>4.9.0-3.23613.4</MicrosoftCodeAnalysisTestUtilitiesPackageVersion>
+    <MicrosoftCodeAnalysisVisualBasicWorkspacesPackageVersion>4.9.0-3.23613.4</MicrosoftCodeAnalysisVisualBasicWorkspacesPackageVersion>
+    <MicrosoftCodeAnalysisWorkspacesCommonPackageVersion>4.9.0-3.23613.4</MicrosoftCodeAnalysisWorkspacesCommonPackageVersion>
+    <MicrosoftCodeAnalysisWorkspacesMSBuildPackageVersion>4.9.0-3.23613.4</MicrosoftCodeAnalysisWorkspacesMSBuildPackageVersion>
+    <MicrosoftVisualStudioLanguageServicesPackageVersion>4.9.0-3.23613.4</MicrosoftVisualStudioLanguageServicesPackageVersion>
     <MicrosoftDotNetXliffTasksPackageVersion>1.0.0-beta.23475.1</MicrosoftDotNetXliffTasksPackageVersion>
     <!--
       Exception - Microsoft.Extensions.ObjectPool and System.Collections.Immutable packages are not updated by automation,
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Common/DefaultRemoteTextLoaderFactory.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Common/DefaultRemoteTextLoaderFactory.cs
index 22c28592bcf..8dcebeeb225 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Common/DefaultRemoteTextLoaderFactory.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Common/DefaultRemoteTextLoaderFactory.cs
@@ -2,6 +2,7 @@
 // Licensed under the MIT license. See License.txt in the project root for license information.
 
 using System;
+using System.Composition;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
@@ -11,7 +12,9 @@
 
 namespace Microsoft.AspNetCore.Razor.LanguageServer.Common;
 
-internal class DefaultRemoteTextLoaderFactory : RemoteTextLoaderFactory
+[Export(typeof(RemoteTextLoaderFactory)), Shared]
+[method: ImportingConstructor]
+internal class DefaultRemoteTextLoaderFactory() : RemoteTextLoaderFactory
 {
     public override TextLoader Create(string filePath)
     {
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/ConfigurableLanguageServerFeatureOptions.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/ConfigurableLanguageServerFeatureOptions.cs
index 7517ce5a2e8..37c46402846 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/ConfigurableLanguageServerFeatureOptions.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/ConfigurableLanguageServerFeatureOptions.cs
@@ -23,6 +23,7 @@ internal class ConfigurableLanguageServerFeatureOptions : LanguageServerFeatureO
     private readonly bool? _updateBuffersForClosedDocuments;
     private readonly bool? _includeProjectKeyInGeneratedFilePath;
     private readonly bool? _monitorWorkspaceFolderForConfigurationFiles;
+    private readonly bool? _useRazorCohostServer;
 
     public override bool SupportsFileManipulation => _supportsFileManipulation ?? _defaults.SupportsFileManipulation;
     public override string ProjectConfigurationFileName => _projectConfigurationFileName ?? _defaults.ProjectConfigurationFileName;
@@ -37,6 +38,7 @@ internal class ConfigurableLanguageServerFeatureOptions : LanguageServerFeatureO
     public override bool UpdateBuffersForClosedDocuments => _updateBuffersForClosedDocuments ?? _defaults.UpdateBuffersForClosedDocuments;
     public override bool IncludeProjectKeyInGeneratedFilePath => _includeProjectKeyInGeneratedFilePath ?? _defaults.IncludeProjectKeyInGeneratedFilePath;
     public override bool MonitorWorkspaceFolderForConfigurationFiles => _monitorWorkspaceFolderForConfigurationFiles ?? _defaults.MonitorWorkspaceFolderForConfigurationFiles;
+    public override bool UseRazorCohostServer => _useRazorCohostServer ?? _defaults.UseRazorCohostServer;
 
     public ConfigurableLanguageServerFeatureOptions(string[] args)
     {
@@ -60,6 +62,7 @@ public ConfigurableLanguageServerFeatureOptions(string[] args)
             TryProcessBoolOption(nameof(UpdateBuffersForClosedDocuments), ref _updateBuffersForClosedDocuments, option, args, i);
             TryProcessBoolOption(nameof(IncludeProjectKeyInGeneratedFilePath), ref _includeProjectKeyInGeneratedFilePath, option, args, i);
             TryProcessBoolOption(nameof(MonitorWorkspaceFolderForConfigurationFiles), ref _monitorWorkspaceFolderForConfigurationFiles, option, args, i);
+            TryProcessBoolOption(nameof(UseRazorCohostServer), ref _useRazorCohostServer, option, args, i);
         }
     }
 
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DefaultLanguageServerFeatureOptions.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DefaultLanguageServerFeatureOptions.cs
index b878599916c..1e7817f5c6e 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DefaultLanguageServerFeatureOptions.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DefaultLanguageServerFeatureOptions.cs
@@ -40,4 +40,6 @@ public override bool ReturnCodeActionAndRenamePathsWithPrefixedSlash
     public override bool UsePreciseSemanticTokenRanges => false;
 
     public override bool MonitorWorkspaceFolderForConfigurationFiles => true;
+
+    public override bool UseRazorCohostServer => false;
 }
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DocumentColor/DocumentColorEndpoint.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DocumentColor/DocumentColorEndpoint.cs
index e583ab7ff75..82b4840abf7 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DocumentColor/DocumentColorEndpoint.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DocumentColor/DocumentColorEndpoint.cs
@@ -4,7 +4,6 @@
 using System;
 using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.AspNetCore.Razor.LanguageServer.Common;
 using Microsoft.AspNetCore.Razor.LanguageServer.EndpointContracts;
 using Microsoft.CommonLanguageServerProtocol.Framework;
 using Microsoft.VisualStudio.LanguageServer.Protocol;
@@ -12,52 +11,19 @@
 namespace Microsoft.AspNetCore.Razor.LanguageServer.DocumentColor;
 
 [LanguageServerEndpoint(Methods.TextDocumentDocumentColorName)]
-internal sealed class DocumentColorEndpoint : IRazorRequestHandler<DocumentColorParams, ColorInformation[]>, ICapabilitiesProvider
+internal sealed class DocumentColorEndpoint(IDocumentColorService documentColorService, IClientConnection clientConnection) : IRazorRequestHandler<DocumentColorParams, ColorInformation[]>, ICapabilitiesProvider
 {
-    private readonly IClientConnection _clientConnection;
-
-    public DocumentColorEndpoint(IClientConnection clientConnection)
-    {
-        _clientConnection = clientConnection ?? throw new ArgumentNullException(nameof(clientConnection));
-    }
+    private readonly IDocumentColorService _documentColorService = documentColorService ?? throw new ArgumentNullException(nameof(documentColorService));
+    private readonly IClientConnection _clientConnection = clientConnection ?? throw new ArgumentNullException(nameof(clientConnection));
 
     public bool MutatesSolutionState => false;
 
     public void ApplyCapabilities(VSInternalServerCapabilities serverCapabilities, VSInternalClientCapabilities clientCapabilities)
-    {
-        serverCapabilities.DocumentColorProvider = new DocumentColorOptions();
-    }
+        => _documentColorService.ApplyCapabilities(serverCapabilities, clientCapabilities);
 
     public TextDocumentIdentifier GetTextDocumentIdentifier(DocumentColorParams request)
         => request.TextDocument;
 
-    public async Task<ColorInformation[]> HandleRequestAsync(DocumentColorParams request, RazorRequestContext requestContext, CancellationToken cancellationToken)
-    {
-        // Workaround for Web Tools bug https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1743689 where they sometimes
-        // send requests for filenames that are stale, possibly due to adornment taggers being cached incorrectly (or caching
-        // filenames incorrectly)
-        if (requestContext.DocumentContext is null)
-        {
-            return Array.Empty<ColorInformation>();
-        }
-
-        var delegatedRequest = new DelegatedDocumentColorParams()
-        {
-            HostDocumentVersion = requestContext.GetRequiredDocumentContext().Version,
-            TextDocument = request.TextDocument
-        };
-
-        var documentColors = await _clientConnection.SendRequestAsync<DelegatedDocumentColorParams, ColorInformation[]>(
-            CustomMessageNames.RazorProvideHtmlDocumentColorEndpoint,
-            delegatedRequest,
-            cancellationToken).ConfigureAwait(false);
-
-        if (documentColors is null)
-        {
-            return Array.Empty<ColorInformation>();
-        }
-
-        // HTML and Razor documents have identical mapping locations. Because of this we can return the result as-is.
-        return documentColors;
-    }
+    public Task<ColorInformation[]> HandleRequestAsync(DocumentColorParams request, RazorRequestContext requestContext, CancellationToken cancellationToken)
+        => _documentColorService.GetColorInformationAsync(_clientConnection, request, requestContext.DocumentContext, cancellationToken);
 }
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DocumentColor/DocumentColorService.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DocumentColor/DocumentColorService.cs
new file mode 100644
index 00000000000..127c7d57284
--- /dev/null
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DocumentColor/DocumentColorService.cs
@@ -0,0 +1,50 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using System.Composition;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Razor.LanguageServer.Common;
+using Microsoft.VisualStudio.LanguageServer.Protocol;
+
+namespace Microsoft.AspNetCore.Razor.LanguageServer.DocumentColor;
+
+[Export(typeof(IDocumentColorService)), Shared]
+[method: ImportingConstructor]
+internal sealed class DocumentColorService() : IDocumentColorService
+{
+    public void ApplyCapabilities(VSInternalServerCapabilities serverCapabilities, VSInternalClientCapabilities clientCapabilities)
+    {
+        serverCapabilities.DocumentColorProvider = new DocumentColorOptions();
+    }
+
+    public async Task<ColorInformation[]> GetColorInformationAsync(IClientConnection clientConnection, DocumentColorParams request, VersionedDocumentContext? documentContext, CancellationToken cancellationToken)
+    {
+        // Workaround for Web Tools bug https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1743689 where they sometimes
+        // send requests for filenames that are stale, possibly due to adornment taggers being cached incorrectly (or caching
+        // filenames incorrectly)
+        if (documentContext is null)
+        {
+            return [];
+        }
+
+        var delegatedRequest = new DelegatedDocumentColorParams()
+        {
+            HostDocumentVersion = documentContext.Version,
+            TextDocument = request.TextDocument
+        };
+
+        var documentColors = await clientConnection.SendRequestAsync<DelegatedDocumentColorParams, ColorInformation[]>(
+            CustomMessageNames.RazorProvideHtmlDocumentColorEndpoint,
+            delegatedRequest,
+            cancellationToken).ConfigureAwait(false);
+
+        if (documentColors is null)
+        {
+            return [];
+        }
+
+        // HTML and Razor documents have identical mapping locations. Because of this we can return the result as-is.
+        return documentColors;
+    }
+}
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DocumentColor/IDocumentColorService.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DocumentColor/IDocumentColorService.cs
new file mode 100644
index 00000000000..d4e266509df
--- /dev/null
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DocumentColor/IDocumentColorService.cs
@@ -0,0 +1,13 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.VisualStudio.LanguageServer.Protocol;
+
+namespace Microsoft.AspNetCore.Razor.LanguageServer.DocumentColor;
+
+internal interface IDocumentColorService : ICapabilitiesProvider
+{
+    Task<ColorInformation[]> GetColorInformationAsync(IClientConnection clientConnection, DocumentColorParams request, VersionedDocumentContext? documentContext, CancellationToken cancellationToken);
+}
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DocumentContextFactory.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DocumentContextFactory.cs
index 708feb93271..4381c4bb246 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DocumentContextFactory.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DocumentContextFactory.cs
@@ -2,6 +2,7 @@
 // Licensed under the MIT license. See License.txt in the project root for license information.
 
 using System;
+using System.Composition;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using Microsoft.AspNetCore.Razor.LanguageServer.Extensions;
@@ -16,6 +17,8 @@
 
 namespace Microsoft.AspNetCore.Razor.LanguageServer;
 
+[Export(typeof(IDocumentContextFactory)), Shared]
+[method: ImportingConstructor]
 internal sealed class DocumentContextFactory(
     ProjectSnapshotManagerAccessor projectSnapshotManagerAccessor,
     ISnapshotResolver snapshotResolver,
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DocumentVersionCache.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DocumentVersionCache.cs
index 0d1f45f6eb5..4df912d238b 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DocumentVersionCache.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DocumentVersionCache.cs
@@ -3,13 +3,19 @@
 
 using System;
 using System.Collections.Generic;
+using System.Composition;
 using System.Diagnostics.CodeAnalysis;
 using Microsoft.CodeAnalysis.Razor;
 using Microsoft.CodeAnalysis.Razor.ProjectSystem;
 
 namespace Microsoft.AspNetCore.Razor.LanguageServer;
 
-internal sealed class DocumentVersionCache : IDocumentVersionCache, IProjectSnapshotChangeTrigger
+// TODO: This has to be Shared for MEF to work, but this service was written assuming its lifetime was that of the language
+//       server, so it doesn't clean up after itself well. In the long run, this hopefully won't matter, as we can remove it
+//       but leaving this note here because you never know.
+[Export(typeof(IDocumentVersionCache)), Shared]
+[method: ImportingConstructor]
+internal sealed class DocumentVersionCache() : IDocumentVersionCache, IProjectSnapshotChangeTrigger
 {
     internal const int MaxDocumentTrackingCount = 20;
 
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/ProjectSystem/DefaultRazorProjectService.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/ProjectSystem/DefaultRazorProjectService.cs
index ae898ed7037..7284685e1f0 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/ProjectSystem/DefaultRazorProjectService.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/ProjectSystem/DefaultRazorProjectService.cs
@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Immutable;
+using System.Composition;
 using System.Diagnostics;
 using System.IO;
 using System.Linq;
@@ -23,60 +24,23 @@
 
 namespace Microsoft.AspNetCore.Razor.LanguageServer.ProjectSystem;
 
-internal class DefaultRazorProjectService : RazorProjectService
+[Export(typeof(RazorProjectService)), Shared]
+[method: ImportingConstructor]
+internal class DefaultRazorProjectService(
+    ProjectSnapshotManagerDispatcher projectSnapshotManagerDispatcher,
+    RemoteTextLoaderFactory remoteTextLoaderFactory,
+    ISnapshotResolver snapshotResolver,
+    IDocumentVersionCache documentVersionCache,
+    ProjectSnapshotManagerAccessor projectSnapshotManagerAccessor,
+    IRazorLoggerFactory loggerFactory)
+    : RazorProjectService
 {
-    private readonly ProjectSnapshotManagerAccessor _projectSnapshotManagerAccessor;
-    private readonly ProjectSnapshotManagerDispatcher _projectSnapshotManagerDispatcher;
-    private readonly RemoteTextLoaderFactory _remoteTextLoaderFactory;
-    private readonly ISnapshotResolver _snapshotResolver;
-    private readonly IDocumentVersionCache _documentVersionCache;
-    private readonly ILogger _logger;
-
-    public DefaultRazorProjectService(
-        ProjectSnapshotManagerDispatcher projectSnapshotManagerDispatcher,
-        RemoteTextLoaderFactory remoteTextLoaderFactory,
-        ISnapshotResolver snapshotResolver,
-        IDocumentVersionCache documentVersionCache,
-        ProjectSnapshotManagerAccessor projectSnapshotManagerAccessor,
-        IRazorLoggerFactory loggerFactory)
-    {
-        if (projectSnapshotManagerDispatcher is null)
-        {
-            throw new ArgumentNullException(nameof(projectSnapshotManagerDispatcher));
-        }
-
-        if (remoteTextLoaderFactory is null)
-        {
-            throw new ArgumentNullException(nameof(remoteTextLoaderFactory));
-        }
-
-        if (snapshotResolver is null)
-        {
-            throw new ArgumentNullException(nameof(snapshotResolver));
-        }
-
-        if (documentVersionCache is null)
-        {
-            throw new ArgumentNullException(nameof(documentVersionCache));
-        }
-
-        if (projectSnapshotManagerAccessor is null)
-        {
-            throw new ArgumentNullException(nameof(projectSnapshotManagerAccessor));
-        }
-
-        if (loggerFactory is null)
-        {
-            throw new ArgumentNullException(nameof(loggerFactory));
-        }
-
-        _projectSnapshotManagerDispatcher = projectSnapshotManagerDispatcher;
-        _remoteTextLoaderFactory = remoteTextLoaderFactory;
-        _snapshotResolver = snapshotResolver;
-        _documentVersionCache = documentVersionCache;
-        _projectSnapshotManagerAccessor = projectSnapshotManagerAccessor;
-        _logger = loggerFactory.CreateLogger<DefaultRazorProjectService>();
-    }
+    private readonly ProjectSnapshotManagerAccessor _projectSnapshotManagerAccessor = projectSnapshotManagerAccessor ?? throw new ArgumentNullException(nameof(projectSnapshotManagerAccessor));
+    private readonly ProjectSnapshotManagerDispatcher _projectSnapshotManagerDispatcher = projectSnapshotManagerDispatcher ?? throw new ArgumentNullException(nameof(projectSnapshotManagerDispatcher));
+    private readonly RemoteTextLoaderFactory _remoteTextLoaderFactory = remoteTextLoaderFactory ?? throw new ArgumentNullException(nameof(remoteTextLoaderFactory));
+    private readonly ISnapshotResolver _snapshotResolver = snapshotResolver ?? throw new ArgumentNullException(nameof(snapshotResolver));
+    private readonly IDocumentVersionCache _documentVersionCache = documentVersionCache ?? throw new ArgumentNullException(nameof(documentVersionCache));
+    private readonly ILogger _logger = loggerFactory.CreateLogger<DefaultRazorProjectService>();
 
     public override void AddDocument(string filePath)
     {
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/ProjectSystem/SnapshotResolver.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/ProjectSystem/SnapshotResolver.cs
index ab68db1ad69..9bb2da71cbc 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/ProjectSystem/SnapshotResolver.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/ProjectSystem/SnapshotResolver.cs
@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Composition;
 using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Linq;
@@ -15,7 +16,8 @@
 
 namespace Microsoft.AspNetCore.Razor.LanguageServer.ProjectSystem;
 
-internal class SnapshotResolver : ISnapshotResolver
+[Export(typeof(ISnapshotResolver)), Shared]
+internal sealed class SnapshotResolver : ISnapshotResolver
 {
     private readonly ProjectSnapshotManagerAccessor _projectSnapshotManagerAccessor;
     private readonly ILogger _logger;
@@ -23,10 +25,11 @@ internal class SnapshotResolver : ISnapshotResolver
     // Internal for testing
     internal readonly HostProject MiscellaneousHostProject;
 
+    [ImportingConstructor]
     public SnapshotResolver(ProjectSnapshotManagerAccessor projectSnapshotManagerAccessor, IRazorLoggerFactory loggerFactory)
     {
         _projectSnapshotManagerAccessor = projectSnapshotManagerAccessor ?? throw new ArgumentNullException(nameof(projectSnapshotManagerAccessor));
-        _logger = loggerFactory.CreateLogger<SnapshotResolver>() ?? throw new ArgumentNullException(nameof(loggerFactory));
+        _logger = loggerFactory.CreateLogger<SnapshotResolver>();
 
         var miscellaneousProjectPath = Path.Combine(TempDirectory.Instance.DirectoryPath, "__MISC_RAZOR_PROJECT__");
         var normalizedPath = FilePathNormalizer.Normalize(miscellaneousProjectPath);
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/RazorDocumentMappingService.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/RazorDocumentMappingService.cs
index 975afcf180c..7bf377cbb13 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/RazorDocumentMappingService.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/RazorDocumentMappingService.cs
@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
+using System.Composition;
 using System.Diagnostics;
 using System.Linq;
 using System.Threading;
@@ -22,21 +23,17 @@
 
 namespace Microsoft.AspNetCore.Razor.LanguageServer;
 
-internal sealed class RazorDocumentMappingService : IRazorDocumentMappingService
-{
-    private readonly FilePathService _documentFilePathService;
-    private readonly IDocumentContextFactory _documentContextFactory;
-    private readonly ILogger _logger;
-
-    public RazorDocumentMappingService(
+[Export(typeof(IRazorDocumentMappingService)), Shared]
+[method: ImportingConstructor]
+internal sealed class RazorDocumentMappingService(
         FilePathService filePathService,
         IDocumentContextFactory documentContextFactory,
         IRazorLoggerFactory loggerFactory)
-    {
-        _documentFilePathService = filePathService ?? throw new ArgumentNullException(nameof(filePathService));
-        _documentContextFactory = documentContextFactory ?? throw new ArgumentNullException(nameof(documentContextFactory));
-        _logger = loggerFactory?.CreateLogger<RazorDocumentMappingService>() ?? throw new ArgumentNullException(nameof(loggerFactory));
-    }
+         : IRazorDocumentMappingService
+{
+    private readonly FilePathService _documentFilePathService = filePathService ?? throw new ArgumentNullException(nameof(filePathService));
+    private readonly IDocumentContextFactory _documentContextFactory = documentContextFactory ?? throw new ArgumentNullException(nameof(documentContextFactory));
+    private readonly ILogger _logger = loggerFactory.CreateLogger<RazorDocumentMappingService>();
 
     public TextEdit[] GetHostDocumentEdits(IRazorGeneratedDocument generatedDocument, TextEdit[] generatedDocumentEdits)
     {
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/RazorLanguageServer.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/RazorLanguageServer.cs
index ab40a466ae9..4c7b4d420ba 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/RazorLanguageServer.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/RazorLanguageServer.cs
@@ -157,13 +157,13 @@ protected override ILspServices ConstructLspServices()
         // Defaults: For when the caller hasn't provided them through the `configure` action.
         services.TryAddSingleton<HostServicesProvider, DefaultHostServicesProvider>();
 
-        AddHandlers(services);
+        AddHandlers(services, featureOptions);
 
         var lspServices = new LspServices(services);
 
         return lspServices;
 
-        static void AddHandlers(IServiceCollection services)
+        static void AddHandlers(IServiceCollection services, LanguageServerFeatureOptions featureOptions)
         {
             // Not calling AddHandler because we want to register this endpoint as an IOnInitialized too
             services.AddSingleton<RazorConfigurationEndpoint>();
@@ -182,7 +182,13 @@ static void AddHandlers(IServiceCollection services)
             services.AddHandler<WrapWithTagEndpoint>();
             services.AddHandler<RazorBreakpointSpanEndpoint>();
             services.AddHandler<RazorProximityExpressionsEndpoint>();
-            services.AddHandlerWithCapabilities<DocumentColorEndpoint>();
+
+            if (!featureOptions.UseRazorCohostServer)
+            {
+                services.AddHandlerWithCapabilities<DocumentColorEndpoint>();
+                services.AddSingleton<IDocumentColorService, DocumentColorService>();
+            }
+
             services.AddHandler<ColorPresentationEndpoint>();
             services.AddHandlerWithCapabilities<FoldingRangeEndpoint>();
             services.AddHandlerWithCapabilities<ValidateBreakpointRangeEndpoint>();
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/Utilities/FilePathNormalizer.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/Utilities/FilePathNormalizer.cs
index 7b11fd7081d..d434e6cd14d 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/Utilities/FilePathNormalizer.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/Utilities/FilePathNormalizer.cs
@@ -3,14 +3,27 @@
 
 using System;
 using System.Buffers;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using Microsoft.CodeAnalysis.Razor;
+using Microsoft.Extensions.Internal;
 
 namespace Microsoft.AspNetCore.Razor.Utilities;
 
 internal static class FilePathNormalizer
 {
+    private static Lazy<IEqualityComparer<string>> _lazyComparer = new Lazy<IEqualityComparer<string>>(() => new FilePathNormalizingComparer());
+    public static IEqualityComparer<string> Comparer => _lazyComparer.Value;
+
+    private class FilePathNormalizingComparer : IEqualityComparer<string>
+    {
+        public bool Equals(string? x, string? y) => FilePathNormalizer.FilePathsEquivalent(x, y);
+
+        public int GetHashCode([DisallowNull] string obj) => FilePathNormalizer.GetHashCode(obj);
+    }
+
     public static string NormalizeDirectory(string? directoryFilePath)
     {
         if (directoryFilePath.IsNullOrEmpty())
@@ -118,6 +131,28 @@ public static bool FilePathsEquivalent(string? filePath1, string? filePath2)
         return normalizedSpan1.Equals(normalizedSpan2, FilePathComparison.Instance);
     }
 
+    public static int GetHashCode(string filePath)
+    {
+        if (filePath.Length == 0)
+        {
+            return filePath.GetHashCode();
+        }
+
+        var filePathSpan = filePath.AsSpanOrDefault();
+
+        using var _ = ArrayPool<char>.Shared.GetPooledArray(filePathSpan.Length, out var array1);
+        var normalizedSpan = NormalizeCoreAndGetSpan(filePathSpan, array1);
+
+        var hashCombiner = HashCodeCombiner.Start();
+
+        foreach (var ch in normalizedSpan)
+        {
+            hashCombiner.Add(ch);
+        }
+
+        return hashCombiner.CombinedHash;
+    }
+
     private static ReadOnlySpan<char> NormalizeCoreAndGetSpan(ReadOnlySpan<char> source, Span<char> destination)
     {
         var (start, length) = NormalizeCore(source, destination);
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/LanguageServerFeatureOptions.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/LanguageServerFeatureOptions.cs
index 9340a7a4450..c1f8327388a 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/LanguageServerFeatureOptions.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/LanguageServerFeatureOptions.cs
@@ -43,4 +43,6 @@ internal abstract class LanguageServerFeatureOptions
     /// razor/monitorProjectConfigurationFilePath notification is sent.
     /// </remarks>
     public abstract bool MonitorWorkspaceFolderForConfigurationFiles { get; }
+
+    public abstract bool UseRazorCohostServer { get; }
 }
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectSnapshot.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectSnapshot.cs
index 9b04777d36f..01ebf44fe96 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectSnapshot.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectSnapshot.cs
@@ -8,6 +8,7 @@
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.PooledObjects;
 using Microsoft.AspNetCore.Razor.ProjectSystem;
+using Microsoft.AspNetCore.Razor.Utilities;
 using Microsoft.CodeAnalysis.CSharp;
 
 namespace Microsoft.CodeAnalysis.Razor.ProjectSystem;
@@ -23,7 +24,7 @@ public ProjectSnapshot(ProjectState state)
         State = state ?? throw new ArgumentNullException(nameof(state));
 
         _lock = new object();
-        _documents = new Dictionary<string, DocumentSnapshot>(FilePathComparer.Instance);
+        _documents = new Dictionary<string, DocumentSnapshot>(FilePathNormalizer.Comparer);
     }
 
     public ProjectKey Key => State.HostProject.Key;
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectState.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectState.cs
index 1a5eae8d6ff..ff0a9dad6a1 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectState.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectState.cs
@@ -9,6 +9,7 @@
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.ProjectSystem;
+using Microsoft.AspNetCore.Razor.Utilities;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.Text;
 
@@ -28,8 +29,8 @@ internal class ProjectState
         ProjectDifference.DocumentAdded |
         ProjectDifference.DocumentRemoved;
 
-    private static readonly ImmutableDictionary<string, DocumentState> s_emptyDocuments = ImmutableDictionary.Create<string, DocumentState>(FilePathComparer.Instance);
-    private static readonly ImmutableDictionary<string, ImmutableArray<string>> s_emptyImportsToRelatedDocuments = ImmutableDictionary.Create<string, ImmutableArray<string>>(FilePathComparer.Instance);
+    private static readonly ImmutableDictionary<string, DocumentState> s_emptyDocuments = ImmutableDictionary.Create<string, DocumentState>(FilePathNormalizer.Comparer);
+    private static readonly ImmutableDictionary<string, ImmutableArray<string>> s_emptyImportsToRelatedDocuments = ImmutableDictionary.Create<string, ImmutableArray<string>>(FilePathNormalizer.Comparer);
     private readonly object _lock;
 
     private readonly ProjectSnapshotProjectEngineFactory _projectEngineFactory;
@@ -357,7 +358,7 @@ public ProjectState WithHostProject(HostProject hostProject)
             return this;
         }
 
-        var documents = Documents.ToImmutableDictionary(kvp => kvp.Key, kvp => kvp.Value.WithConfigurationChange(), FilePathComparer.Instance);
+        var documents = Documents.ToImmutableDictionary(kvp => kvp.Key, kvp => kvp.Value.WithConfigurationChange(), FilePathNormalizer.Comparer);
 
         // If the host project has changed then we need to recompute the imports map
         var importsToRelatedDocuments = s_emptyImportsToRelatedDocuments;
@@ -385,7 +386,7 @@ public ProjectState WithProjectWorkspaceState(ProjectWorkspaceState projectWorks
         }
 
         var difference = ProjectDifference.ProjectWorkspaceStateChanged;
-        var documents = Documents.ToImmutableDictionary(kvp => kvp.Key, kvp => kvp.Value.WithProjectWorkspaceStateChange(), FilePathComparer.Instance);
+        var documents = Documents.ToImmutableDictionary(kvp => kvp.Key, kvp => kvp.Value.WithProjectWorkspaceStateChange(), FilePathNormalizer.Comparer);
         var state = new ProjectState(this, difference, HostProject, projectWorkspaceState, documents, ImportsToRelatedDocuments);
         return state;
     }
@@ -441,7 +442,7 @@ public List<string> GetImportDocumentTargetPaths(HostDocument hostDocument)
         {
             var itemTargetPath = importItem.FilePath.Replace('/', '\\').TrimStart('\\');
 
-            if (FilePathComparer.Instance.Equals(itemTargetPath, hostDocument.TargetPath))
+            if (FilePathNormalizer.Comparer.Equals(itemTargetPath, hostDocument.TargetPath))
             {
                 // We've normalized the original importItem.FilePath into the HostDocument.TargetPath. For instance, if the HostDocument.TargetPath
                 // was '/_Imports.razor' it'd be normalized down into '_Imports.razor'. The purpose of this method is to get the associated document
diff --git a/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/CohostDocumentColorEndpoint.cs b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/CohostDocumentColorEndpoint.cs
new file mode 100644
index 00000000000..b3e8a48e0a7
--- /dev/null
+++ b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/CohostDocumentColorEndpoint.cs
@@ -0,0 +1,59 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using System.Composition;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Razor.LanguageServer;
+using Microsoft.AspNetCore.Razor.LanguageServer.DocumentColor;
+using Microsoft.CodeAnalysis.ExternalAccess.Razor.Cohost;
+using Microsoft.CodeAnalysis.Razor.Logging;
+using Microsoft.CommonLanguageServerProtocol.Framework;
+using Microsoft.Extensions.Logging;
+using Microsoft.VisualStudio.LanguageServer.Protocol;
+using Microsoft.VisualStudio.LanguageServerClient.Razor.Extensions;
+
+namespace Microsoft.VisualStudio.LanguageServerClient.Razor.Cohost;
+
+[LanguageServerEndpoint(Methods.TextDocumentDocumentColorName)]
+[ExportRazorStatelessLspService(typeof(CohostDocumentColorEndpoint))]
+[Export(typeof(ICapabilitiesProvider))]
+[method: ImportingConstructor]
+internal sealed class CohostDocumentColorEndpoint(
+    IDocumentColorService documentColorService,
+    IDocumentContextFactory documentContextFactory,
+    IRazorLoggerFactory loggerFactory)
+    : AbstractRazorCohostDocumentRequestHandler<DocumentColorParams, ColorInformation[]>, ICapabilitiesProvider
+{
+    private readonly IDocumentColorService _documentColorService = documentColorService;
+    private readonly IDocumentContextFactory _documentContextFactory = documentContextFactory;
+    private readonly ILogger _logger = loggerFactory.CreateLogger<CohostDocumentColorEndpoint>();
+
+    protected override bool MutatesSolutionState => false;
+    protected override bool RequiresLSPSolution => true;
+
+    protected override RazorTextDocumentIdentifier? GetRazorTextDocumentIdentifier(DocumentColorParams request)
+        => request.TextDocument.ToRazorTextDocumentIdentifier();
+
+    public void ApplyCapabilities(VSInternalServerCapabilities serverCapabilities, VSInternalClientCapabilities clientCapabilities)
+        => _documentColorService.ApplyCapabilities(serverCapabilities, clientCapabilities);
+
+    protected override Task<ColorInformation[]> HandleRequestAsync(DocumentColorParams request, RazorCohostRequestContext context, CancellationToken cancellationToken)
+    {
+        // TODO: Create document context from request.TextDocument, by looking at request.Solution instead of our project snapshots
+        var documentContext = _documentContextFactory.TryCreateForOpenDocument(request.TextDocument);
+
+        _logger.LogDebug("[Cohost] Received document color request for {requestPath} and got document {documentPath}", request.TextDocument.Uri, documentContext?.FilePath);
+
+        // TODO: We can't MEF import IRazorCohostClientLanguageServerManager in the constructor. We can make this work
+        //       by having it implement a base class, RazorClientConnectionBase or something, that in turn implements
+        //       AbstractRazorLspService (defined in Roslyn) and then move everything from importing IClientConnection
+        //       to importing the new base class, so we can continue to share services.
+        //
+        //       Until then we have to get the service from the request context.
+        var clientLanguageServerManager = context.GetRequiredService<IRazorCohostClientLanguageServerManager>();
+        var clientConnection = new RazorCohostClientConnection(clientLanguageServerManager);
+
+        return _documentColorService.GetColorInformationAsync(clientConnection, request, documentContext, cancellationToken);
+    }
+}
diff --git a/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/DidChangeHandler.cs b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/DidChangeHandler.cs
new file mode 100644
index 00000000000..d6bf9d299b5
--- /dev/null
+++ b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/DidChangeHandler.cs
@@ -0,0 +1,28 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using System;
+using System.Composition;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Razor.LanguageServer.ProjectSystem;
+using Microsoft.CodeAnalysis.ExternalAccess.Razor.Cohost;
+using Microsoft.CodeAnalysis.Razor;
+using Microsoft.CodeAnalysis.Text;
+
+namespace Microsoft.VisualStudio.LanguageServerClient.Razor.Cohost;
+
+[Export(typeof(IRazorCohostDidChangeHandler)), Shared]
+[method: ImportingConstructor]
+internal class DidChangeHandler(ProjectSnapshotManagerDispatcher projectSnapshotManagerDispatcher, RazorProjectService razorProjectService) : IRazorCohostDidChangeHandler
+{
+    private readonly ProjectSnapshotManagerDispatcher _projectSnapshotManagerDispatcher = projectSnapshotManagerDispatcher;
+    private readonly RazorProjectService _razorProjectService = razorProjectService;
+
+    public Task HandleAsync(Uri uri, int version, SourceText sourceText, CancellationToken cancellationToken)
+    {
+        return _projectSnapshotManagerDispatcher.RunOnDispatcherThreadAsync(
+            () => _razorProjectService.UpdateDocument(uri.GetAbsoluteOrUNCPath(), sourceText, version),
+            cancellationToken);
+    }
+}
diff --git a/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/DidCloseHandler.cs b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/DidCloseHandler.cs
new file mode 100644
index 00000000000..f5a8a45f526
--- /dev/null
+++ b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/DidCloseHandler.cs
@@ -0,0 +1,27 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using System;
+using System.Composition;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Razor.LanguageServer.ProjectSystem;
+using Microsoft.CodeAnalysis.ExternalAccess.Razor.Cohost;
+using Microsoft.CodeAnalysis.Razor;
+
+namespace Microsoft.VisualStudio.LanguageServerClient.Razor.Cohost;
+
+[Export(typeof(IRazorCohostDidCloseHandler)), Shared]
+[method: ImportingConstructor]
+internal class DidCloseHandler(ProjectSnapshotManagerDispatcher projectSnapshotManagerDispatcher, RazorProjectService razorProjectService) : IRazorCohostDidCloseHandler
+{
+    private readonly ProjectSnapshotManagerDispatcher _projectSnapshotManagerDispatcher = projectSnapshotManagerDispatcher;
+    private readonly RazorProjectService _razorProjectService = razorProjectService;
+
+    public Task HandleAsync(Uri uri, CancellationToken cancellationToken)
+    {
+        return _projectSnapshotManagerDispatcher.RunOnDispatcherThreadAsync(
+            () => _razorProjectService.CloseDocument(uri.GetAbsoluteOrUNCPath()),
+            cancellationToken);
+    }
+}
diff --git a/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/DidOpenHandler.cs b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/DidOpenHandler.cs
new file mode 100644
index 00000000000..f69c4b0bae0
--- /dev/null
+++ b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/DidOpenHandler.cs
@@ -0,0 +1,28 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using System;
+using System.Composition;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Razor.LanguageServer.ProjectSystem;
+using Microsoft.CodeAnalysis.ExternalAccess.Razor.Cohost;
+using Microsoft.CodeAnalysis.Razor;
+using Microsoft.CodeAnalysis.Text;
+
+namespace Microsoft.VisualStudio.LanguageServerClient.Razor.Cohost;
+
+[Export(typeof(IRazorCohostDidOpenHandler)), Shared]
+[method: ImportingConstructor]
+internal class DidOpenHandler(ProjectSnapshotManagerDispatcher projectSnapshotManagerDispatcher, RazorProjectService razorProjectService) : IRazorCohostDidOpenHandler
+{
+    private readonly ProjectSnapshotManagerDispatcher _projectSnapshotManagerDispatcher = projectSnapshotManagerDispatcher;
+    private readonly RazorProjectService _razorProjectService = razorProjectService;
+
+    public Task HandleAsync(Uri uri, int version, SourceText sourceText, CancellationToken cancellationToken)
+    {
+        return _projectSnapshotManagerDispatcher.RunOnDispatcherThreadAsync(
+            () => _razorProjectService.OpenDocument(uri.GetAbsoluteOrUNCPath(), sourceText, version),
+            cancellationToken);
+    }
+}
diff --git a/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/RazorCohostCapabilitiesProvider.cs b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/RazorCohostCapabilitiesProvider.cs
new file mode 100644
index 00000000000..9e486174fc9
--- /dev/null
+++ b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/RazorCohostCapabilitiesProvider.cs
@@ -0,0 +1,33 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition;
+using Microsoft.AspNetCore.Razor.LanguageServer;
+using Microsoft.CodeAnalysis.ExternalAccess.Razor.Cohost;
+using Microsoft.VisualStudio.LanguageServer.Protocol;
+using Newtonsoft.Json;
+
+namespace Microsoft.VisualStudio.LanguageServerClient.Razor.Cohost;
+
+[Export(typeof(IRazorCohostCapabilitiesProvider)), System.Composition.Shared]
+[method: ImportingConstructor]
+internal class RazorCohostCapabilitiesProvider([ImportMany(typeof(ICapabilitiesProvider))] IEnumerable<Lazy<ICapabilitiesProvider>> cohostCapabilitiesProviders) : IRazorCohostCapabilitiesProvider
+{
+    private readonly IEnumerable<Lazy<ICapabilitiesProvider>> _cohostCapabilitiesProviders = cohostCapabilitiesProviders;
+
+    public string GetCapabilities(string clientCapabilities)
+    {
+        var clientCapabilitiesObject = JsonConvert.DeserializeObject<VSInternalClientCapabilities>(clientCapabilities) ?? new();
+
+        var serverCapabilities = new VSInternalServerCapabilities();
+
+        foreach (var provider in _cohostCapabilitiesProviders)
+        {
+            provider.Value.ApplyCapabilities(serverCapabilities, clientCapabilitiesObject);
+        }
+
+        return JsonConvert.SerializeObject(serverCapabilities);
+    }
+}
diff --git a/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/RazorCohostClientNotifierService.cs b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/RazorCohostClientNotifierService.cs
new file mode 100644
index 00000000000..330cc204020
--- /dev/null
+++ b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/RazorCohostClientNotifierService.cs
@@ -0,0 +1,23 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Razor.LanguageServer;
+using Microsoft.CodeAnalysis.ExternalAccess.Razor.Cohost;
+
+namespace Microsoft.VisualStudio.LanguageServerClient.Razor.Cohost;
+
+internal sealed class RazorCohostClientConnection(IRazorCohostClientLanguageServerManager clientNotifier) : IClientConnection
+{
+    private readonly IRazorCohostClientLanguageServerManager _clientNotifier = clientNotifier;
+
+    public Task SendNotificationAsync<TParams>(string method, TParams @params, CancellationToken cancellationToken)
+        => _clientNotifier.SendNotificationAsync<TParams>(method, @params, cancellationToken).AsTask();
+
+    public Task SendNotificationAsync(string method, CancellationToken cancellationToken)
+        => _clientNotifier.SendNotificationAsync(method, cancellationToken).AsTask();
+
+    public Task<TResponse> SendRequestAsync<TParams, TResponse>(string method, TParams @params, CancellationToken cancellationToken)
+        => _clientNotifier.SendRequestAsync<TParams, TResponse>(method, @params, cancellationToken);
+}
diff --git a/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/RazorCohostLanguageClientActivationService.cs b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/RazorCohostLanguageClientActivationService.cs
new file mode 100644
index 00000000000..aabaee16957
--- /dev/null
+++ b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/RazorCohostLanguageClientActivationService.cs
@@ -0,0 +1,20 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using System.Composition;
+using Microsoft.CodeAnalysis.ExternalAccess.Razor.Cohost;
+using Microsoft.CodeAnalysis.Razor.Workspaces;
+
+namespace Microsoft.VisualStudio.LanguageServerClient.Razor.Cohost;
+
+[Export(typeof(IRazorCohostLanguageClientActivationService)), Shared]
+[method: ImportingConstructor]
+internal class RazorCohostLanguageClientActivationService(LanguageServerFeatureOptions languageServerFeatureOptions) : IRazorCohostLanguageClientActivationService
+{
+    private readonly LanguageServerFeatureOptions _languageServerFeatureOptions = languageServerFeatureOptions;
+
+    public bool ShouldActivateCohostServer()
+    {
+        return _languageServerFeatureOptions.UseRazorCohostServer;
+    }
+}
diff --git a/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Extensions/TextDocumentExtensions.cs b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Extensions/TextDocumentExtensions.cs
index 5fbfd30aa15..56f0f120914 100644
--- a/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Extensions/TextDocumentExtensions.cs
+++ b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Extensions/TextDocumentExtensions.cs
@@ -2,9 +2,11 @@
 // Licensed under the MIT license. See License.txt in the project root for license information.
 
 using System;
+using Microsoft.CodeAnalysis.ExternalAccess.Razor.Cohost;
 using Microsoft.VisualStudio.LanguageServer.Protocol;
 
 namespace Microsoft.VisualStudio.LanguageServerClient.Razor.Extensions;
+
 internal static class TextDocumentExtensions
 {
     /// <summary>
@@ -15,4 +17,7 @@ public static TextDocumentIdentifier WithUri(this TextDocumentIdentifier textDoc
         textDocumentIdentifier.Uri = uri;
         return textDocumentIdentifier;
     }
+
+    public static RazorTextDocumentIdentifier ToRazorTextDocumentIdentifier(this TextDocumentIdentifier textDocumentIdentifier)
+        => new RazorTextDocumentIdentifier(textDocumentIdentifier.Uri, (textDocumentIdentifier as VSTextDocumentIdentifier)?.ProjectContext?.Id);
 }
diff --git a/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Microsoft.VisualStudio.LanguageServerClient.Razor.csproj b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Microsoft.VisualStudio.LanguageServerClient.Razor.csproj
index 93c84fe78f0..c8e19089f11 100644
--- a/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Microsoft.VisualStudio.LanguageServerClient.Razor.csproj
+++ b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Microsoft.VisualStudio.LanguageServerClient.Razor.csproj
@@ -27,6 +27,8 @@
     <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="$(MicrosoftExtensionsPackageVersion)" />
     <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="$(MicrosoftExtensionsPackageVersion)" />
 
+    <PackageReference Include="Microsoft.CodeAnalysis.ExternalAccess.Razor" Version="$(MicrosoftCodeAnalysisExternalAccessRazorPackageVersion)" />
+
     <!--
       Pinning packages to avoid misaligned reference CI failures.
       CI builds here: https://github.com/dotnet/razor-tooling/issues/4327
diff --git a/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/RazorCustomMessageTarget.cs b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/RazorCustomMessageTarget.cs
index d00a8225630..f2d0980454b 100644
--- a/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/RazorCustomMessageTarget.cs
+++ b/src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/RazorCustomMessageTarget.cs
@@ -10,6 +10,7 @@
 using Microsoft.AspNetCore.Razor.LanguageServer.Extensions;
 using Microsoft.AspNetCore.Razor.LanguageServer.Protocol;
 using Microsoft.AspNetCore.Razor.Telemetry;
+using Microsoft.CodeAnalysis.ExternalAccess.Razor.Cohost;
 using Microsoft.CodeAnalysis.Razor.Logging;
 using Microsoft.CodeAnalysis.Razor.ProjectSystem;
 using Microsoft.CodeAnalysis.Razor.Workspaces;
@@ -24,8 +25,9 @@
 
 namespace Microsoft.VisualStudio.LanguageServerClient.Razor;
 
+[Export(typeof(IRazorCustomMessageTarget))]
 [Export(typeof(RazorCustomMessageTarget))]
-internal partial class RazorCustomMessageTarget
+internal partial class RazorCustomMessageTarget : IRazorCustomMessageTarget
 {
     private readonly TrackingLSPDocumentManager _documentManager;
     private readonly JoinableTaskFactory _joinableTaskFactory;
diff --git a/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/VisualStudioWindowsLanguageServerFeatureOptions.cs b/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/VisualStudioWindowsLanguageServerFeatureOptions.cs
index 71255a86de4..952c44cfa35 100644
--- a/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/VisualStudioWindowsLanguageServerFeatureOptions.cs
+++ b/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/VisualStudioWindowsLanguageServerFeatureOptions.cs
@@ -15,11 +15,13 @@ internal class VisualStudioWindowsLanguageServerFeatureOptions : LanguageServerF
     private const string ShowAllCSharpCodeActionsFeatureFlag = "Razor.LSP.ShowAllCSharpCodeActions";
     private const string IncludeProjectKeyInGeneratedFilePathFeatureFlag = "Razor.LSP.IncludeProjectKeyInGeneratedFilePath";
     private const string UsePreciseSemanticTokenRangesFeatureFlag = "Razor.LSP.UsePreciseSemanticTokenRanges";
+    private const string UseRazorCohostServerFeatureFlag = "Razor.LSP.UseRazorCohostServer";
 
     private readonly LSPEditorFeatureDetector _lspEditorFeatureDetector;
     private readonly Lazy<bool> _showAllCSharpCodeActions;
     private readonly Lazy<bool> _includeProjectKeyInGeneratedFilePath;
     private readonly Lazy<bool> _usePreciseSemanticTokenRanges;
+    private readonly Lazy<bool> _useRazorCohostServer;
 
     [ImportingConstructor]
     public VisualStudioWindowsLanguageServerFeatureOptions(LSPEditorFeatureDetector lspEditorFeatureDetector)
@@ -51,6 +53,13 @@ public VisualStudioWindowsLanguageServerFeatureOptions(LSPEditorFeatureDetector
             var usePreciseSemanticTokenRanges = featureFlags.IsFeatureEnabled(UsePreciseSemanticTokenRangesFeatureFlag, defaultValue: false);
             return usePreciseSemanticTokenRanges;
         });
+
+        _useRazorCohostServer = new Lazy<bool>(() =>
+        {
+            var featureFlags = (IVsFeatureFlags)AsyncPackage.GetGlobalService(typeof(SVsFeatureFlags));
+            var useRazorCohostServer = featureFlags.IsFeatureEnabled(UseRazorCohostServerFeatureFlag, defaultValue: false);
+            return useRazorCohostServer;
+        });
     }
 
     // We don't currently support file creation operations on VS Codespaces or VS Liveshare
@@ -82,4 +91,6 @@ public VisualStudioWindowsLanguageServerFeatureOptions(LSPEditorFeatureDetector
     public override bool UsePreciseSemanticTokenRanges => _usePreciseSemanticTokenRanges.Value;
 
     public override bool MonitorWorkspaceFolderForConfigurationFiles => false;
+
+    public override bool UseRazorCohostServer => _useRazorCohostServer.Value;
 }
diff --git a/src/Razor/src/Microsoft.VisualStudio.RazorExtension/Microsoft.VisualStudio.RazorExtension.Custom.pkgdef b/src/Razor/src/Microsoft.VisualStudio.RazorExtension/Microsoft.VisualStudio.RazorExtension.Custom.pkgdef
index eb4f0e03f98..46cecf5c420 100644
--- a/src/Razor/src/Microsoft.VisualStudio.RazorExtension/Microsoft.VisualStudio.RazorExtension.Custom.pkgdef
+++ b/src/Razor/src/Microsoft.VisualStudio.RazorExtension/Microsoft.VisualStudio.RazorExtension.Custom.pkgdef
@@ -62,3 +62,9 @@
 "Title"="Use precise semantic token ranges when requesting semantic token information on Razor files (requires restart)"
 "PreviewPaneChannels"="*"
 "VisibleToInternalUsersOnlyChannels"="*"
+
+[$RootKey$\FeatureFlags\Razor\LSP\UseRazorCohostServer]
+"Description"="Uses the Razor language server that is cohosted in Roslyn to provide some Razor tooling functionality."
+"Value"=dword:00000000
+"Title"="Use Roslyn Cohost server for Razor (requires restart)"
+"PreviewPaneChannels"="IntPreview,int.main"
\ No newline at end of file
diff --git a/src/Razor/src/Microsoft.VisualStudio.RazorExtension/source.extension.vsixmanifest b/src/Razor/src/Microsoft.VisualStudio.RazorExtension/source.extension.vsixmanifest
index 7be499eaae6..bb183cdee0f 100644
--- a/src/Razor/src/Microsoft.VisualStudio.RazorExtension/source.extension.vsixmanifest
+++ b/src/Razor/src/Microsoft.VisualStudio.RazorExtension/source.extension.vsixmanifest
@@ -50,6 +50,7 @@
     <Asset Type="Microsoft.VisualStudio.Assembly" Path="System.Runtime.CompilerServices.Unsafe.dll" />
     <Asset Type="Microsoft.VisualStudio.Assembly" Path="System.Threading.Channels.dll" />
     <Asset Type="Microsoft.VisualStudio.Assembly" Path="Microsoft.AspNetCore.Razor.LanguageServer.dll" />
+    <Asset Type="Microsoft.VisualStudio.MefComponent" Path="Microsoft.AspNetCore.Razor.LanguageServer.dll" />
     <Asset Type="Microsoft.VisualStudio.Assembly" Path="Microsoft.AspNetCore.Razor.LanguageSupport.dll" />
     <Asset Type="Microsoft.VisualStudio.Assembly" Path="Microsoft.AspNetCore.Razor.LanguageServer.Protocol.dll" />
     <Asset Type="Microsoft.VisualStudio.MefComponent" Path="Microsoft.CodeAnalysis.Razor.Compiler.Language.dll" />
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CodeActionEndToEndTest.NetFx.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CodeActionEndToEndTest.NetFx.cs
index 525472d5f3c..502ce7c7f3a 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CodeActionEndToEndTest.NetFx.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CodeActionEndToEndTest.NetFx.cs
@@ -140,7 +140,7 @@ void M(string[] args)
         await ValidateCodeActionAsync(input, expected, RazorPredefinedCodeRefactoringProviderNames.IntroduceVariable);
     }
 
-    [Fact]
+    [Fact(Skip = "https://github.com/dotnet/roslyn/issues/71335")]
     public async Task Handle_IntroduceLocal_All()
     {
         var input = """
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/Workspaces/TestLanguageServerFeatureOptions.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/Workspaces/TestLanguageServerFeatureOptions.cs
index 686d390ed3e..ac07721dbe4 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/Workspaces/TestLanguageServerFeatureOptions.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/Workspaces/TestLanguageServerFeatureOptions.cs
@@ -45,4 +45,6 @@ public TestLanguageServerFeatureOptions(
     public override bool IncludeProjectKeyInGeneratedFilePath => _includeProjectKeyInGeneratedFilePath;
 
     public override bool MonitorWorkspaceFolderForConfigurationFiles => _monitorWorkspaceFolderForConfigurationFiles;
+
+    public override bool UseRazorCohostServer => throw new System.NotImplementedException();
 }
diff --git a/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/ProjectSystem/FallbackWindowsRazorProjectHostTest.cs b/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/ProjectSystem/FallbackWindowsRazorProjectHostTest.cs
index 6ed4e81eee9..0a46be9aa54 100644
--- a/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/ProjectSystem/FallbackWindowsRazorProjectHostTest.cs
+++ b/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/ProjectSystem/FallbackWindowsRazorProjectHostTest.cs
@@ -7,6 +7,7 @@
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Diagnostics.CodeAnalysis;
+using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Test.Common.Editor;
@@ -387,9 +388,9 @@ public async Task OnProjectChanged_ReadsProperties_InitializesProject()
         Assert.Same(FallbackRazorConfiguration.MVC_2_0, snapshot.Configuration);
 
         Assert.Collection(
-            snapshot.DocumentFilePaths,
-            filePath => Assert.Equal("C:\\Path\\Index.cshtml", filePath),
-            filePath => Assert.Equal("C:\\Path\\About.cshtml", filePath));
+            snapshot.DocumentFilePaths.OrderBy(d => d),
+            filePath => Assert.Equal("C:\\Path\\About.cshtml", filePath),
+            filePath => Assert.Equal("C:\\Path\\Index.cshtml", filePath));
 
         await Task.Run(async () => await host.DisposeAsync());
         Assert.Empty(_projectManager.GetProjects());