diff --git a/Security/Common/Domain/User.cs b/Security/Common/Domain/User.cs
index bc8bf46..2dafb97 100644
--- a/Security/Common/Domain/User.cs
+++ b/Security/Common/Domain/User.cs
@@ -8,7 +8,7 @@ public enum TwoFactorAuthenticator
 
 public class User
 {
-    public required int Id { get; set; }
+    public required string Id { get; set; }
     public required string Username { get; set; }
     public required string Email { get; set; }
     public required string PasswordHash { get; set; }
diff --git a/Security/Services/AuthService.cs b/Security/Services/AuthService.cs
index 8b542d6..93bd37a 100644
--- a/Security/Services/AuthService.cs
+++ b/Security/Services/AuthService.cs
@@ -131,13 +131,13 @@ public class AuthService(ICacheService cache, IAccessToken accessTokenService, I
 
         if (user.TwoFactorAuthenticator == TwoFactorAuthenticator.None)
         {
-            await GenerateAuthTokensAsync(cookieOptions, context, requestContext, user.Id.ToString(), cancellation);
+            await GenerateAuthTokensAsync(cookieOptions, context, requestContext, user.Id, cancellation);
             return TwoFactorAuthenticator.None;
         }
 
         var firstAuthToken = new FirstAuthToken(requestContext)
         {
-            UserId = user.Id.ToString(),
+            UserId = user.Id,
             Secret = user.SecondFactorToken,
             TwoFactorAuthenticator = user.TwoFactorAuthenticator
         };