diff --git a/Directory.Build.props b/Directory.Build.props
index d755160..6b9ec43 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -12,7 +12,7 @@
   <PropertyGroup>
     <PasswordlessMajorVersion>1</PasswordlessMajorVersion>
     <PasswordlessMinorVersion>0</PasswordlessMinorVersion>
-    <PasswordlessPatchVersion>2</PasswordlessPatchVersion>
+    <PasswordlessPatchVersion>3</PasswordlessPatchVersion>
     <PasswordlessMajorMinorVersion>$(PasswordlessMajorVersion).$(PasswordlessMinorVersion)</PasswordlessMajorMinorVersion>
     <VersionPrefix>$(PasswordlessMajorMinorVersion).$(PasswordlessPatchVersion)</VersionPrefix>
   </PropertyGroup>
diff --git a/src/Sdk/Helpers/PasswordlessSerializerContext.cs b/src/Sdk/Helpers/PasswordlessSerializerContext.cs
index 451122c..f75a51f 100644
--- a/src/Sdk/Helpers/PasswordlessSerializerContext.cs
+++ b/src/Sdk/Helpers/PasswordlessSerializerContext.cs
@@ -7,6 +7,7 @@ namespace Passwordless.Net.Helpers;
 [JsonSourceGenerationOptions(
     PropertyNamingPolicy = JsonKnownNamingPolicy.CamelCase,
     DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull)]
+[JsonSerializable(typeof(AddAliasRequest))]
 [JsonSerializable(typeof(RegisterTokenResponse))]
 [JsonSerializable(typeof(RegisterOptions))]
 [JsonSerializable(typeof(VerifyTokenRequest))] // TODO: Use this with JsonContent.Create
diff --git a/src/Sdk/IPasswordlessClient.cs b/src/Sdk/IPasswordlessClient.cs
index 1683f1e..ef1d6e8 100644
--- a/src/Sdk/IPasswordlessClient.cs
+++ b/src/Sdk/IPasswordlessClient.cs
@@ -7,6 +7,14 @@ namespace Passwordless.Net;
 /// </summary>
 public interface IPasswordlessClient
 {
+    /// <summary>
+    /// Adds one or more aliases to an existing user.
+    /// </summary>
+    /// <param name="request"></param>
+    /// <param name="cancellationToken"></param>
+    /// <returns></returns>
+    Task AddAliasAsync(AddAliasRequest request, CancellationToken cancellationToken = default);
+
     /// <summary>
     /// Creates a <see cref="RegisterTokenResponse" /> which will be used by your frontend to negotiate
     /// the creation of a WebAuth credential.
diff --git a/src/Sdk/Models/AddAliasRequest.cs b/src/Sdk/Models/AddAliasRequest.cs
new file mode 100644
index 0000000..5230f6e
--- /dev/null
+++ b/src/Sdk/Models/AddAliasRequest.cs
@@ -0,0 +1,36 @@
+namespace Passwordless.Net.Models;
+
+public class AddAliasRequest
+{
+    public AddAliasRequest(string userId, string alias, bool hashing = true)
+        : this(userId, hashing)
+    {
+        if (string.IsNullOrWhiteSpace(alias)) throw new ArgumentException($"'{nameof(alias)}' cannot be null, empty or whitespace.");
+        Aliases = new HashSet<string>
+        {
+            alias ?? throw new ArgumentNullException(nameof(alias))
+        };
+    }
+
+    public AddAliasRequest(string userId, HashSet<string> aliases, bool hashing = true)
+        : this(userId, hashing)
+    {
+        if (aliases == null || !aliases.Any()) throw new ArgumentException($"'{nameof(aliases)}' cannot be null or empty.");
+        if (aliases.Any(string.IsNullOrWhiteSpace)) throw new ArgumentException("One of the aliases is null, empty or whitespace");
+        Aliases = aliases;
+    }
+
+    private AddAliasRequest(string userId, bool hashing = true)
+    {
+        UserId = userId ?? throw new ArgumentNullException(nameof(userId));
+        Hashing = hashing;
+    }
+
+    public string UserId { get; }
+    public HashSet<string> Aliases { get; }
+
+    /// <summary>
+    /// If you want your aliases to be available in plain text, set the <see cref="bool"/> false.
+    /// </summary>
+    public bool Hashing { get; } = true;
+}
\ No newline at end of file
diff --git a/src/Sdk/PasswordlessClient.cs b/src/Sdk/PasswordlessClient.cs
index db9048f..e9b354e 100644
--- a/src/Sdk/PasswordlessClient.cs
+++ b/src/Sdk/PasswordlessClient.cs
@@ -1,8 +1,6 @@
 using System.Diagnostics;
-using System.Net.Http;
 using System.Net.Http.Json;
 using System.Text;
-using Passwordless.Net.Helpers;
 using Passwordless.Net.Models;
 using JsonContext = Passwordless.Net.Helpers.PasswordlessSerializerContext;
 
@@ -41,6 +39,16 @@ public PasswordlessClient(HttpClient client)
         _client = client;
     }
 
+    /// <inheritdoc/>
+    public async Task AddAliasAsync(AddAliasRequest request, CancellationToken cancellationToken)
+    {
+        var res = await _client.PostAsJsonAsync("alias",
+            request,
+            JsonContext.Default.AddAliasRequest,
+            cancellationToken);
+        res.EnsureSuccessStatusCode();
+    }
+
     /// <inheritdoc/>
     public async Task<RegisterTokenResponse> CreateRegisterTokenAsync(RegisterOptions registerOptions, CancellationToken cancellationToken = default)
     {