diff --git a/src/infrastructure/DigitalData.MessagingService.Infrastructure/DependencyInjection.cs b/src/infrastructure/DigitalData.MessagingService.Infrastructure/DependencyInjection.cs
index 8b713f6..7958361 100644
--- a/src/infrastructure/DigitalData.MessagingService.Infrastructure/DependencyInjection.cs
+++ b/src/infrastructure/DigitalData.MessagingService.Infrastructure/DependencyInjection.cs
@@ -29,8 +29,17 @@ public static class DependencyInjection
         IConfiguration configuration)
     {
         // --- External Services ---
+        // OAuth2 token services — provider-specific implementations registered separately,
+        // dispatcher is the single IOAuth2TokenService consumed by all other services.
+        services.AddSingleton<MicrosoftOAuth2TokenService>();
+        services.AddSingleton<GoogleOAuth2TokenService>();
+        services.AddSingleton<IOAuth2TokenService, OAuth2TokenServiceDispatcher>();
+
+        services.AddHttpClient(nameof(GoogleOAuth2TokenService));
+        services.AddHttpClient(nameof(GoogleOAuth2AuthorizationService));
+        services.AddSingleton<IOAuth2AuthorizationService, GoogleOAuth2AuthorizationService>();
+
         // Email Service - SMTP outbound (Limilabs Mail.dll) - OAuth2 aware
-        services.AddSingleton<IOAuth2TokenService, MicrosoftOAuth2TokenService>();
         services.AddSingleton<LimilabsEmailService>();
         services.AddSingleton<IEmailService>(sp => sp.GetRequiredService<LimilabsEmailService>());
 
diff --git a/src/infrastructure/DigitalData.MessagingService.Infrastructure/DigitalData.MessagingService.Infrastructure.csproj b/src/infrastructure/DigitalData.MessagingService.Infrastructure/DigitalData.MessagingService.Infrastructure.csproj
index fabd55c..91eaa7c 100644
--- a/src/infrastructure/DigitalData.MessagingService.Infrastructure/DigitalData.MessagingService.Infrastructure.csproj
+++ b/src/infrastructure/DigitalData.MessagingService.Infrastructure/DigitalData.MessagingService.Infrastructure.csproj
@@ -23,6 +23,7 @@
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
     <PackageReference Include="Microsoft.Extensions.Hosting" Version="10.0.10" />
+    <PackageReference Include="Microsoft.Extensions.Http" Version="8.0.1" />
     <PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="10.0.10" />
     <PackageReference Include="Microsoft.Identity.Client" Version="4.65.0" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" Version="8.0.11" />