diff --git a/README.md b/README.md
index c8625f9..0a4d06b 100644
--- a/README.md
+++ b/README.md
@@ -17,31 +17,28 @@ For use outside of ASP.NET Core, see the
 [configuration](source/VMelnalksnis.NordigenDotNet.DependencyInjection/ServiceCollectionExtensions.cs).
 
 1. Add configuration (for optional values see [options](source/VMelnalksnis.NordigenDotNet/NordigenOptions.cs))
+   ```yaml
+   "Nordigen": {
+       "SecretId": "",
+       "SecretKey": ""
+   }
+   ```
 
-```yaml
-"Nordigen": {
-    "SecretId": "",
-    "SecretKey": ""
-}
-```
-
-2. Register required services
-
-```csharp
-// Only registers services from NordigenDotNet
-services.AddNordigenDotNet(Configuration);
-// Also registers the IDateTimeZoneProvider, which is required
-serviceCollection.AddNordigenDotNet(Configuration, SystemClock.Instance, DateTimeZoneProviders.Tzdb);
-```
+2. Register required services (see [tests](tests/VMelnalksnis.NordigenDotNet.DependencyInjection.Tests/ServiceCollectionExtensionsTests.cs))
+   ```csharp
+   serviceCollection
+       .AddSingleton<IClock>(SystemClock.Instance)
+       .AddSingleton(DateTimeZoneProviders.Tzdb)
+       .AddNordigenDotNet(configuration);
+   ```
 
 3. (Optional) Configure retries
    with [Polly](https://github.com/App-vNext/Polly) ([NuGet package](https://www.nuget.org/packages/Microsoft.Extensions.Http.Polly))
-
-```csharp
-services
-	.AddNordigenDotNet(Configuration, SystemClock.Instance, DateTimeZoneProviders.Tzdb)
-	.AddPolicyHandler(...);
-```
+   ```csharp
+   serviceCollection
+       .AddNordigenDotNet(configuration)
+       .AddPolicyHandler(...);
+   ```
 
 4. Use `INordigenClient` to access all endpoints, or one of the specific clients defined in `INordigenClient`
 
diff --git a/source/VMelnalksnis.NordigenDotNet.DependencyInjection/ServiceCollectionExtensions.cs b/source/VMelnalksnis.NordigenDotNet.DependencyInjection/ServiceCollectionExtensions.cs
index baaeefd..86cafe6 100644
--- a/source/VMelnalksnis.NordigenDotNet.DependencyInjection/ServiceCollectionExtensions.cs
+++ b/source/VMelnalksnis.NordigenDotNet.DependencyInjection/ServiceCollectionExtensions.cs
@@ -12,11 +12,8 @@ using JetBrains.Annotations;
 
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Extensions.DependencyInjection.Extensions;
 using Microsoft.Extensions.Options;
 
-using NodaTime;
-
 using VMelnalksnis.NordigenDotNet.Accounts;
 using VMelnalksnis.NordigenDotNet.Agreements;
 using VMelnalksnis.NordigenDotNet.Institutions;
@@ -39,23 +36,6 @@ public static class ServiceCollectionExtensions
 		_userAgent = new(assemblyShortName, assemblyName.Version?.ToString());
 	}
 
-	/// <summary>Adds all required services for <see cref="INordigenClient"/>.</summary>
-	/// <param name="serviceCollection">The service collection in which to register the services.</param>
-	/// <param name="configuration">The configuration to which to bind options models.</param>
-	/// <param name="clock">Clock for accessing the current time.</param>
-	/// <param name="dateTimeZoneProvider">Time zone provider for date and time serialization.</param>
-	/// <returns>The <see cref="IHttpClientBuilder"/> for the <see cref="HttpClient"/> used by <see cref="INordigenClient"/>.</returns>
-	public static IHttpClientBuilder AddNordigenDotNet(
-		this IServiceCollection serviceCollection,
-		IConfiguration configuration,
-		IClock clock,
-		IDateTimeZoneProvider dateTimeZoneProvider)
-	{
-		serviceCollection.TryAddSingleton(clock);
-		serviceCollection.TryAddSingleton(dateTimeZoneProvider);
-		return serviceCollection.AddNordigenDotNet(configuration);
-	}
-
 	/// <summary>Adds all required services for <see cref="INordigenClient"/>, excluding external dependencies.</summary>
 	/// <param name="serviceCollection">The service collection in which to register the services.</param>
 	/// <param name="configuration">The configuration to which to bind options models.</param>
diff --git a/tests/VMelnalksnis.NordigenDotNet.DependencyInjection.Tests/ServiceCollectionExtensionsTests.cs b/tests/VMelnalksnis.NordigenDotNet.DependencyInjection.Tests/ServiceCollectionExtensionsTests.cs
index 70fb37e..49128be 100644
--- a/tests/VMelnalksnis.NordigenDotNet.DependencyInjection.Tests/ServiceCollectionExtensionsTests.cs
+++ b/tests/VMelnalksnis.NordigenDotNet.DependencyInjection.Tests/ServiceCollectionExtensionsTests.cs
@@ -27,7 +27,10 @@ public sealed class ServiceCollectionExtensionsTests
 
 		var serviceCollection = new ServiceCollection();
 
-		serviceCollection.AddNordigenDotNet(configuration, SystemClock.Instance, DateTimeZoneProviders.Tzdb);
+		serviceCollection
+			.AddSingleton<IClock>(SystemClock.Instance)
+			.AddSingleton(DateTimeZoneProviders.Tzdb)
+			.AddNordigenDotNet(configuration);
 
 		var serviceProvider = serviceCollection.BuildServiceProvider();
 		var nordigenClient = serviceProvider.GetRequiredService<INordigenClient>();
diff --git a/tests/VMelnalksnis.NordigenDotNet.Tests.Integration/ServiceProviderFixture.cs b/tests/VMelnalksnis.NordigenDotNet.Tests.Integration/ServiceProviderFixture.cs
index f133a5e..758d93b 100644
--- a/tests/VMelnalksnis.NordigenDotNet.Tests.Integration/ServiceProviderFixture.cs
+++ b/tests/VMelnalksnis.NordigenDotNet.Tests.Integration/ServiceProviderFixture.cs
@@ -40,7 +40,12 @@ public sealed class ServiceProviderFixture
 			.Build();
 
 		var serviceCollection = new ServiceCollection();
-		serviceCollection.AddNordigenDotNet(configuration, Clock, DateTimeZoneProviders.Tzdb);
+
+		serviceCollection
+			.AddSingleton<IClock>(Clock)
+			.AddSingleton(DateTimeZoneProviders.Tzdb)
+			.AddNordigenDotNet(configuration);
+
 		serviceCollection.AddLogging(builder =>
 		{
 			var logger = new LoggerConfiguration()