diff --git a/API-reference.md b/API-reference.md
index 82530f5..85aadd4 100644
--- a/API-reference.md
+++ b/API-reference.md
@@ -31,5 +31,9 @@
 
 ## EugeneFox.SimpleOTP.DependencyInjection package
 
-> [!NOTE]
-This section is still in development.
+- **SimpleOTP.DependencyInjection**
+	- [IOtpService](./simpleotp.dependencyinjection.iotpservice)
+	- [OtpOptions](./simpleotp.dependencyinjection.otpoptions)
+	- [OtpServiceConfig](./simpleotp.dependencyinjection.otpserviceconfig)
+	- [OtpServiceExtensions](./simpleotp.dependencyinjection.otpserviceextensions)
+	- [ToleranceSpanConfig](./simpleotp.dependencyinjection.tolerancespanconfig)
diff --git a/simpleotp.dependencyinjection.iotpservice.md b/simpleotp.dependencyinjection.iotpservice.md
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@@ -0,0 +1,84 @@
+# IOtpService
+
+Namespace: SimpleOTP.DependencyInjection
+
+Provides methods for generating and validating One-Time Passwords.
+
+```csharp
+public interface IOtpService
+```
+
+Attributes [NullableContextAttribute](https://docs.microsoft.com/en-us/dotnet/api/system.runtime.compilerservices.nullablecontextattribute)
+
+## Methods
+
+### **CreateUri(String, OtpSecret, Int64)**
+
+Creates an OTP URI for specified user and secret.
+
+```csharp
+Uri CreateUri(string username, OtpSecret secret, long counter)
+```
+
+#### Parameters
+
+`username` [String](https://docs.microsoft.com/en-us/dotnet/api/system.string)<br>
+The username of the user.
+
+`secret` OtpSecret<br>
+The secret to use.
+
+`counter` [Int64](https://docs.microsoft.com/en-us/dotnet/api/system.int64)<br>
+(only for HOTP) The counter to use.
+
+#### Returns
+
+Uri<br>
+The generated URI.
+
+### **GenerateCode(OtpSecret, Int64)**
+
+Creates an OTP code for specified user and secret.
+
+```csharp
+OtpCode GenerateCode(OtpSecret secret, long counter)
+```
+
+#### Parameters
+
+`secret` OtpSecret<br>
+The secret to use.
+
+`counter` [Int64](https://docs.microsoft.com/en-us/dotnet/api/system.int64)<br>
+(only for HOTP) The counter to use.
+
+#### Returns
+
+OtpCode<br>
+
+### **ValidateCode(OtpCode, OtpSecret, Int32&, Int64)**
+
+Validates an OTP code for specified user and secret.
+
+```csharp
+bool ValidateCode(OtpCode code, OtpSecret secret, Int32& resyncValue, long counter)
+```
+
+#### Parameters
+
+`code` OtpCode<br>
+The code to validate.
+
+`secret` OtpSecret<br>
+The secret to use.
+
+`resyncValue` [Int32&](https://docs.microsoft.com/en-us/dotnet/api/system.int32&)<br>
+The resync value. Shows how much the code is ahead or behind the current counter value.
+
+`counter` [Int64](https://docs.microsoft.com/en-us/dotnet/api/system.int64)<br>
+(only for HOTP) The counter to use.
+
+#### Returns
+
+[Boolean](https://docs.microsoft.com/en-us/dotnet/api/system.boolean)<br>
+`true` if the code is valid; otherwise, `false`.
diff --git a/simpleotp.dependencyinjection.otpoptions.md b/simpleotp.dependencyinjection.otpoptions.md
new file mode 100644
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+++ b/simpleotp.dependencyinjection.otpoptions.md
@@ -0,0 +1,140 @@
+# OtpOptions
+
+Namespace: SimpleOTP.DependencyInjection
+
+Provides options for the One-Time Password service.
+
+```csharp
+public class OtpOptions
+```
+
+Inheritance [Object](https://docs.microsoft.com/en-us/dotnet/api/system.object) → [OtpOptions](simpleotp.dependencyinjection.otpoptions)<br>
+Attributes [NullableContextAttribute](https://docs.microsoft.com/en-us/dotnet/api/system.runtime.compilerservices.nullablecontextattribute), [NullableAttribute](https://docs.microsoft.com/en-us/dotnet/api/system.runtime.compilerservices.nullableattribute), [RequiredMemberAttribute](https://docs.microsoft.com/en-us/dotnet/api/system.runtime.compilerservices.requiredmemberattribute)
+
+## Properties
+
+### **Issuer**
+
+The name of the issuer.
+
+```csharp
+public string Issuer { get; set; }
+```
+
+#### Property Value
+
+[String](https://docs.microsoft.com/en-us/dotnet/api/system.string)<br>
+
+### **IssuerDomain**
+
+The issuer domain.
+
+```csharp
+public string IssuerDomain { get; set; }
+```
+
+#### Property Value
+
+[String](https://docs.microsoft.com/en-us/dotnet/api/system.string)<br>
+
+**Remarks:**
+
+IMPORTANT: Using this property will imply adherence to the Apple specification.
+
+### **Algorithm**
+
+The algorithm to use.
+
+```csharp
+public OtpAlgorithm Algorithm { get; set; }
+```
+
+#### Property Value
+
+OtpAlgorithm<br>
+
+### **Digits**
+
+The number of digits in the OTP code.
+
+```csharp
+public int Digits { get; set; }
+```
+
+#### Property Value
+
+[Int32](https://docs.microsoft.com/en-us/dotnet/api/system.int32)<br>
+
+### **Period**
+
+The number of seconds between each OTP code.
+
+```csharp
+public int Period { get; set; }
+```
+
+#### Property Value
+
+[Int32](https://docs.microsoft.com/en-us/dotnet/api/system.int32)<br>
+
+### **Type**
+
+The type of One-Time Password to generate.
+
+```csharp
+public OtpType Type { get; set; }
+```
+
+#### Property Value
+
+OtpType<br>
+
+### **UriFormat**
+
+The format of OTP URIs.
+
+```csharp
+public OtpUriFormat UriFormat { get; set; }
+```
+
+#### Property Value
+
+OtpUriFormat<br>
+
+### **ToleranceSpan**
+
+The tolerance span for the OTP codes validation.
+
+```csharp
+public ToleranceSpan ToleranceSpan { get; set; }
+```
+
+#### Property Value
+
+ToleranceSpan<br>
+
+### **CustomProperties**
+
+Custom properties to place in OTP URIs.
+
+```csharp
+public NameValueCollection CustomProperties { get; }
+```
+
+#### Property Value
+
+NameValueCollection<br>
+
+## Constructors
+
+### **OtpOptions()**
+
+#### Caution
+
+Constructors of types with required members are not supported in this version of your compiler.
+
+---
+
+```csharp
+public OtpOptions()
+```
diff --git a/simpleotp.dependencyinjection.otpserviceconfig.md b/simpleotp.dependencyinjection.otpserviceconfig.md
new file mode 100644
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--- /dev/null
+++ b/simpleotp.dependencyinjection.otpserviceconfig.md
@@ -0,0 +1,146 @@
+# OtpServiceConfig
+
+Namespace: SimpleOTP.DependencyInjection
+
+Configuration for the One-Time Password service.
+
+```csharp
+public class OtpServiceConfig
+```
+
+Inheritance [Object](https://docs.microsoft.com/en-us/dotnet/api/system.object) → [OtpServiceConfig](simpleotp.dependencyinjection.otpserviceconfig)<br>
+Attributes [NullableContextAttribute](https://docs.microsoft.com/en-us/dotnet/api/system.runtime.compilerservices.nullablecontextattribute), [NullableAttribute](https://docs.microsoft.com/en-us/dotnet/api/system.runtime.compilerservices.nullableattribute)
+
+## Properties
+
+### **Issuer**
+
+The name of the issuer.
+
+```csharp
+public string Issuer { get; set; }
+```
+
+#### Property Value
+
+[String](https://docs.microsoft.com/en-us/dotnet/api/system.string)<br>
+
+### **IssuerDomain**
+
+The issuer domain.
+
+```csharp
+public string IssuerDomain { get; set; }
+```
+
+#### Property Value
+
+[String](https://docs.microsoft.com/en-us/dotnet/api/system.string)<br>
+
+**Remarks:**
+
+IMPORTANT: Using this property will imply adherence to the Apple specification.
+
+### **Algorithm**
+
+The algorithm to use.
+
+```csharp
+public OtpAlgorithm Algorithm { get; set; }
+```
+
+#### Property Value
+
+OtpAlgorithm<br>
+
+### **Digits**
+
+The number of digits in the OTP code.
+
+```csharp
+public int Digits { get; set; }
+```
+
+#### Property Value
+
+[Int32](https://docs.microsoft.com/en-us/dotnet/api/system.int32)<br>
+
+### **Period**
+
+The number of seconds between each OTP code.
+
+```csharp
+public int Period { get; set; }
+```
+
+#### Property Value
+
+[Int32](https://docs.microsoft.com/en-us/dotnet/api/system.int32)<br>
+
+### **Type**
+
+The type of One-Time Password to generate.
+
+```csharp
+public OtpType Type { get; set; }
+```
+
+#### Property Value
+
+OtpType<br>
+
+### **UriFormat**
+
+The format of OTP URIs.
+
+```csharp
+public OtpUriFormat UriFormat { get; set; }
+```
+
+#### Property Value
+
+OtpUriFormat<br>
+
+### **MinimalUri**
+
+Whether to use minimal URI formatting (only required, or altered properties are included), or full URI formatting.
+
+```csharp
+public bool MinimalUri { get; set; }
+```
+
+#### Property Value
+
+[Boolean](https://docs.microsoft.com/en-us/dotnet/api/system.boolean)<br>
+
+### **ToleranceSpan**
+
+The tolerance span for the OTP codes validation.
+
+```csharp
+public ToleranceSpanConfig ToleranceSpan { get; set; }
+```
+
+#### Property Value
+
+[ToleranceSpanConfig](simpleotp.dependencyinjection.tolerancespanconfig)<br>
+
+### **CustomProperties**
+
+Custom properties to place in OTP URIs.
+
+```csharp
+public Dictionary<string, string> CustomProperties { get; }
+```
+
+#### Property Value
+
+[Dictionary&lt;String, String&gt;](https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.dictionary-2)<br>
+
+## Constructors
+
+### **OtpServiceConfig()**
+
+```csharp
+public OtpServiceConfig()
+```
diff --git a/simpleotp.dependencyinjection.otpserviceextensions.md b/simpleotp.dependencyinjection.otpserviceextensions.md
new file mode 100644
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--- /dev/null
+++ b/simpleotp.dependencyinjection.otpserviceextensions.md
@@ -0,0 +1,104 @@
+# OtpServiceExtensions
+
+Namespace: SimpleOTP.DependencyInjection
+
+Extension methods for the One-Time Password service.
+
+```csharp
+public static class OtpServiceExtensions
+```
+
+Inheritance [Object](https://docs.microsoft.com/en-us/dotnet/api/system.object) → [OtpServiceExtensions](simpleotp.dependencyinjection.otpserviceextensions)<br>
+Attributes [NullableContextAttribute](https://docs.microsoft.com/en-us/dotnet/api/system.runtime.compilerservices.nullablecontextattribute), [NullableAttribute](https://docs.microsoft.com/en-us/dotnet/api/system.runtime.compilerservices.nullableattribute), [ExtensionAttribute](https://docs.microsoft.com/en-us/dotnet/api/system.runtime.compilerservices.extensionattribute)
+
+## Methods
+
+### **AddAuthenticator(IServiceCollection, String)**
+
+Adds the One-Time Password service to the service collection.
+
+```csharp
+public static IServiceCollection AddAuthenticator(IServiceCollection services, string issuerName)
+```
+
+#### Parameters
+
+`services` IServiceCollection<br>
+The service collection.
+
+`issuerName` [String](https://docs.microsoft.com/en-us/dotnet/api/system.string)<br>
+The issuer/application/service name.
+
+#### Returns
+
+IServiceCollection<br>
+A reference to this instance after the operation has completed.
+
+### **AddAuthenticator(IServiceCollection, String, Action&lt;OtpOptions&gt;)**
+
+Adds the One-Time Password service to the service collection.
+
+```csharp
+public static IServiceCollection AddAuthenticator(IServiceCollection services, string issuerName, Action<OtpOptions> configure)
+```
+
+#### Parameters
+
+`services` IServiceCollection<br>
+The service collection.
+
+`issuerName` [String](https://docs.microsoft.com/en-us/dotnet/api/system.string)<br>
+The issuer/application/service name.
+
+`configure` [Action&lt;OtpOptions&gt;](https://docs.microsoft.com/en-us/dotnet/api/system.action-1)<br>
+The configuration for the One-Time Password service.
+
+#### Returns
+
+IServiceCollection<br>
+A reference to this instance after the operation has completed.
+
+### **AddAuthenticator(IServiceCollection, IConfiguration)**
+
+Adds the One-Time Password service to the service collection.
+
+```csharp
+public static IServiceCollection AddAuthenticator(IServiceCollection services, IConfiguration configuration)
+```
+
+#### Parameters
+
+`services` IServiceCollection<br>
+The service collection.
+
+`configuration` IConfiguration<br>
+The configuration for the One-Time Password service.
+
+#### Returns
+
+IServiceCollection<br>
+A reference to this instance after the operation has completed.
+
+### **AddAuthenticator(IServiceCollection, IConfiguration, Action&lt;OtpOptions&gt;)**
+
+Adds the One-Time Password service to the service collection.
+
+```csharp
+public static IServiceCollection AddAuthenticator(IServiceCollection services, IConfiguration configuration, Action<OtpOptions> configure)
+```
+
+#### Parameters
+
+`services` IServiceCollection<br>
+The service collection.
+
+`configuration` IConfiguration<br>
+The configuration for the One-Time Password service.
+
+`configure` [Action&lt;OtpOptions&gt;](https://docs.microsoft.com/en-us/dotnet/api/system.action-1)<br>
+The configuration for the One-Time Password service.
+
+#### Returns
+
+IServiceCollection<br>
+A reference to this instance after the operation has completed.
diff --git a/simpleotp.dependencyinjection.tolerancespanconfig.md b/simpleotp.dependencyinjection.tolerancespanconfig.md
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--- /dev/null
+++ b/simpleotp.dependencyinjection.tolerancespanconfig.md
@@ -0,0 +1,45 @@
+# ToleranceSpanConfig
+
+Namespace: SimpleOTP.DependencyInjection
+
+Configuration for the tolerance span.
+
+```csharp
+public class ToleranceSpanConfig
+```
+
+Inheritance [Object](https://docs.microsoft.com/en-us/dotnet/api/system.object) → [ToleranceSpanConfig](simpleotp.dependencyinjection.tolerancespanconfig)
+
+## Properties
+
+### **Behind**
+
+The number of periods/counter values behind the current value.
+
+```csharp
+public int Behind { get; set; }
+```
+
+#### Property Value
+
+[Int32](https://docs.microsoft.com/en-us/dotnet/api/system.int32)<br>
+
+### **Ahead**
+
+The number of periods/counter values ahead of the current value.
+
+```csharp
+public int Ahead { get; set; }
+```
+
+#### Property Value
+
+[Int32](https://docs.microsoft.com/en-us/dotnet/api/system.int32)<br>
+
+## Constructors
+
+### **ToleranceSpanConfig()**
+
+```csharp
+public ToleranceSpanConfig()
+```