diff --git a/src/StoneRed.NetificationApi/Server/IdentifyUser/IdentifyUserData.cs b/src/StoneRed.NetificationApi/Server/IdentifyUser/IdentifyUserData.cs
index 92fbefa..795cc04 100644
--- a/src/StoneRed.NetificationApi/Server/IdentifyUser/IdentifyUserData.cs
+++ b/src/StoneRed.NetificationApi/Server/IdentifyUser/IdentifyUserData.cs
@@ -1,5 +1,4 @@
-using System.Diagnostics.CodeAnalysis;
-using System.Text.Json.Serialization;
+using System.Text.Json.Serialization;
 
 namespace StoneRed.NetificationApi.Server.IdentifyUser;
 
@@ -8,12 +7,6 @@ namespace StoneRed.NetificationApi.Server.IdentifyUser;
 /// </summary>
 public class IdentifyUserData
 {
-    /// <summary>
-    /// Gets or sets the user ID.
-    /// </summary>
-    [JsonIgnore]
-    public required string UserId { get; set; }
-
     /// <summary>
     /// Gets or sets the email address of the user.
     /// </summary>
@@ -34,21 +27,4 @@ public class IdentifyUserData
     /// Gets or sets the list of web push tokens for the user.
     /// </summary>
     public List<NotificationWebPushToken>? WebPushTokens { get; set; }
-
-    /// <summary>
-    /// Initializes a new instance of the <see cref="IdentifyUserData"/> class with the specified user ID.
-    /// </summary>
-    /// <param name="userId">The user ID.</param>
-    [SetsRequiredMembers]
-    public IdentifyUserData(string userId)
-    {
-        UserId = userId;
-    }
-
-    /// <summary>
-    /// Initializes a new instance of the <see cref="IdentifyUserData"/> class.
-    /// </summary>
-    public IdentifyUserData()
-    {
-    }
 }
\ No newline at end of file
diff --git a/src/StoneRed.NetificationApi/Server/NotificationApiServer.cs b/src/StoneRed.NetificationApi/Server/NotificationApiServer.cs
index 803ac97..34538dd 100644
--- a/src/StoneRed.NetificationApi/Server/NotificationApiServer.cs
+++ b/src/StoneRed.NetificationApi/Server/NotificationApiServer.cs
@@ -76,31 +76,26 @@ public class NotificationApiServer
     /// <summary>
     /// Identifies a user.
     /// </summary>
+    /// <param name="userId">The ID of the user.</param>
     /// <param name="identifyUserData">The data for identifying the user.</param>
     /// <returns>The HTTP response message.</returns>
-    public async Task<HttpResponseMessage> Identify(IdentifyUserData identifyUserData)
+    public async Task<HttpResponseMessage> Identify(string userId, IdentifyUserData identifyUserData)
     {
         string authToken;
 
         if (secureMode)
         {
-            string hashedUserId = UserIdHasher.Hash(identifyUserData.UserId, clientSecret);
-            authToken = Convert.ToBase64String(Encoding.ASCII.GetBytes($"{clientId}:{identifyUserData.UserId}:{hashedUserId}"));
+            string hashedUserId = UserIdHasher.Hash(userId, clientSecret);
+            authToken = Convert.ToBase64String(Encoding.ASCII.GetBytes($"{clientId}:{userId}:{hashedUserId}"));
         }
         else
         {
-            authToken = Convert.ToBase64String(Encoding.ASCII.GetBytes($"{clientId}:{identifyUserData.UserId}"));
+            authToken = Convert.ToBase64String(Encoding.ASCII.GetBytes($"{clientId}:{userId}"));
         }
 
-        var requestData = new
+        HttpRequestMessage request = new(HttpMethod.Post, $"users/{userId}")
         {
-            email = identifyUserData.Email,
-            number = identifyUserData.TelephoneNumber,
-        };
-
-        HttpRequestMessage request = new(HttpMethod.Post, $"users/{identifyUserData.UserId}")
-        {
-            Content = JsonContent.Create(requestData, options: Configuration.JsonSerializerOptions),
+            Content = JsonContent.Create(identifyUserData, options: Configuration.JsonSerializerOptions),
         };
 
         request.Headers.Add("Authorization", $"Basic {authToken}");
@@ -111,10 +106,11 @@ public class NotificationApiServer
     /// <summary>
     /// Sets user preferences.
     /// </summary>
+    /// <param name="userId">The ID of the user.</param>
     /// <param name="setUserPreferencesData">The data for setting user preferences.</param>
     /// <returns>The HTTP response message.</returns>
-    public async Task<HttpResponseMessage> SetUserPreferences(SetUserPreferencesData setUserPreferencesData)
+    public async Task<HttpResponseMessage> SetUserPreferences(string userId, SetUserPreferencesData setUserPreferencesData)
     {
-        return await httpClient.PostAsJsonAsync($"user_preferences/{setUserPreferencesData.UserId}", setUserPreferencesData, Configuration.JsonSerializerOptions);
+        return await httpClient.PostAsJsonAsync($"user_preferences/{userId}", setUserPreferencesData, Configuration.JsonSerializerOptions);
     }
 }
\ No newline at end of file
diff --git a/src/StoneRed.NetificationApi/Server/SetUserPreferences/SetUserPreferencesData.cs b/src/StoneRed.NetificationApi/Server/SetUserPreferences/SetUserPreferencesData.cs
index 5e7be5f..42eb949 100644
--- a/src/StoneRed.NetificationApi/Server/SetUserPreferences/SetUserPreferencesData.cs
+++ b/src/StoneRed.NetificationApi/Server/SetUserPreferences/SetUserPreferencesData.cs
@@ -1,5 +1,4 @@
 using System.Diagnostics.CodeAnalysis;
-using System.Text.Json.Serialization;
 
 namespace StoneRed.NetificationApi.Server.SetUserPreferences;
 
@@ -8,12 +7,6 @@ namespace StoneRed.NetificationApi.Server.SetUserPreferences;
 /// </summary>
 public class SetUserPreferencesData
 {
-    /// <summary>
-    /// Gets or sets the user ID.
-    /// </summary>
-    [JsonIgnore]
-    public required string UserId { get; set; }
-
     /// <summary>
     /// Gets or sets the list of notification preferences.
     /// </summary>
@@ -22,12 +15,10 @@ public class SetUserPreferencesData
     /// <summary>
     /// Initializes a new instance of the <see cref="SetUserPreferencesData"/> class.
     /// </summary>
-    /// <param name="userId">The user ID.</param>
     /// <param name="preferences">The list of notification preferences.</param>
     [SetsRequiredMembers]
-    public SetUserPreferencesData(string userId, List<NotificationPreference> preferences)
+    public SetUserPreferencesData(List<NotificationPreference> preferences)
     {
-        UserId = userId;
         Preferences = preferences;
     }