diff --git a/src/Bluesky.NET/ApiClients/BlueskyApiClient.Actor.cs b/src/Bluesky.NET/ApiClients/BlueskyApiClient.Actor.cs
index 83b8cc6..005bfc0 100644
--- a/src/Bluesky.NET/ApiClients/BlueskyApiClient.Actor.cs
+++ b/src/Bluesky.NET/ApiClients/BlueskyApiClient.Actor.cs
@@ -17,7 +17,7 @@ partial class BlueskyApiClient
 {
     public async Task<Author?> GetAuthorAsync(string accessToken, string identifier)
     {
-        var timelineUrl = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.ProfilePath}?actor={identifier}";
+        var timelineUrl = $"{_baseUrl}/{UrlConstants.ProfilePath}?actor={identifier}";
         HttpRequestMessage message = new(HttpMethod.Get, timelineUrl);
         message.Headers.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
 
@@ -56,7 +56,7 @@ public async Task<Result<FeedResponse>> GetSuggestedPeopleAsync(
             count = 100;
         }
 
-        var url = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.SuggestedPeoplePath}?limit={count}";
+        var url = $"{_baseUrl}/{UrlConstants.SuggestedPeoplePath}?limit={count}";
         if (cursor is { Length: > 0 })
         {
             url += $"&cursor={cursor}";
@@ -78,7 +78,7 @@ public async Task<bool> FollowActorAsync(
         string subjectDid,
         CancellationToken ct)
     {
-        var url = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.CreateRecordPath}";
+        var url = $"{_baseUrl}/{UrlConstants.CreateRecordPath}";
 
         FollowRecordBody body = new()
         {
diff --git a/src/Bluesky.NET/ApiClients/BlueskyApiClient.Blob.cs b/src/Bluesky.NET/ApiClients/BlueskyApiClient.Blob.cs
index 1600441..e509f1c 100644
--- a/src/Bluesky.NET/ApiClients/BlueskyApiClient.Blob.cs
+++ b/src/Bluesky.NET/ApiClients/BlueskyApiClient.Blob.cs
@@ -14,7 +14,7 @@ partial class BlueskyApiClient
 {
     public async Task<Blob?> UploadBlobAsync(string accessToken, byte[] blob, string mimeType)
     {
-        var url = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.UploadBlobPath}";
+        var url = $"{_baseUrl}/{UrlConstants.UploadBlobPath}";
 
         HttpRequestMessage message = new(HttpMethod.Post, url)
         {
diff --git a/src/Bluesky.NET/ApiClients/BlueskyApiClient.FeedGenerators.cs b/src/Bluesky.NET/ApiClients/BlueskyApiClient.FeedGenerators.cs
index 26d94d0..e9810ac 100644
--- a/src/Bluesky.NET/ApiClients/BlueskyApiClient.FeedGenerators.cs
+++ b/src/Bluesky.NET/ApiClients/BlueskyApiClient.FeedGenerators.cs
@@ -26,7 +26,7 @@ public async Task<Result<IReadOnlyList<FeedGenerator>>> GetFeedGeneratorsAsync(
 
         string combined = string.Join("&", feedParameters);
 
-        var url = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.FeedGeneratorsPath}?{combined}";
+        var url = $"{_baseUrl}/{UrlConstants.FeedGeneratorsPath}?{combined}";
         HttpRequestMessage message = new(HttpMethod.Get, url);
         message.Headers.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
 
@@ -46,7 +46,7 @@ public async Task<Result<FeedResponse>> GetSuggestedFeedGeneratorsAsync(
         CancellationToken ct,
         string? cursor = null)
     {
-        var url = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.SuggestedFeedsPath}";
+        var url = $"{_baseUrl}/{UrlConstants.SuggestedFeedsPath}";
         if (cursor is { Length: > 0 })
         {
             url += $"?cursor={cursor}";
diff --git a/src/Bluesky.NET/ApiClients/BlueskyApiClient.Feeds.cs b/src/Bluesky.NET/ApiClients/BlueskyApiClient.Feeds.cs
index 5e9f506..88d8661 100644
--- a/src/Bluesky.NET/ApiClients/BlueskyApiClient.Feeds.cs
+++ b/src/Bluesky.NET/ApiClients/BlueskyApiClient.Feeds.cs
@@ -24,7 +24,7 @@ public async Task<Result<FeedResponse>> GetFeedAsync(
     {
         ct.ThrowIfCancellationRequested();
 
-        var url = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.FeedPath}?feed={atUri}";
+        var url = $"{_baseUrl}/{UrlConstants.FeedPath}?feed={atUri}";
         if (cursor is { Length: > 0 } cursorParameter)
         {
             url += $"&cursor={cursorParameter}";
@@ -45,7 +45,7 @@ public async Task<Result<FeedResponse>> GetFeedAsync(
 
     public async Task<FeedResponse> GetTimelineAsync(string accesstoken, string? cursor = null)
     {
-        var timelineUrl = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.TimelinePath}";
+        var timelineUrl = $"{_baseUrl}/{UrlConstants.TimelinePath}";
         if (cursor is { Length: > 0 } cursorParameter)
         {
             timelineUrl += $"?cursor={cursorParameter}";
@@ -74,7 +74,7 @@ public async Task<FeedResponse> GetTimelineAsync(string accesstoken, string? cur
 
     public async Task<IReadOnlyList<FeedItem>> GetAuthorFeedAsync(string accesstoken, string handle)
     {
-        var feedUrl = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.AuthorFeedPath}?actor={handle}";
+        var feedUrl = $"{_baseUrl}/{UrlConstants.AuthorFeedPath}?actor={handle}";
         HttpRequestMessage message = new(HttpMethod.Get, feedUrl);
         message.Headers.Authorization = new AuthenticationHeaderValue("Bearer", accesstoken);
 
diff --git a/src/Bluesky.NET/ApiClients/BlueskyApiClient.Notifications.cs b/src/Bluesky.NET/ApiClients/BlueskyApiClient.Notifications.cs
index 5840b84..09af1d7 100644
--- a/src/Bluesky.NET/ApiClients/BlueskyApiClient.Notifications.cs
+++ b/src/Bluesky.NET/ApiClients/BlueskyApiClient.Notifications.cs
@@ -16,7 +16,7 @@ partial class BlueskyApiClient
 {
     public async Task<IReadOnlyList<Notification>> GetNotificationsAsync(string accessToken)
     {
-        var url = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.NotificationsPath}";
+        var url = $"{_baseUrl}/{UrlConstants.NotificationsPath}";
         HttpRequestMessage message = new(HttpMethod.Get, url);
         message.Headers.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
 
@@ -35,7 +35,7 @@ public async Task<IReadOnlyList<Notification>> GetNotificationsAsync(string acce
     /// <inheritdoc/>
     public async Task<Result> UpdateSeenAsync(string accessToken, CancellationToken ct)
     {
-        var url = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.UpdateSeenPath}";
+        var url = $"{_baseUrl}/{UrlConstants.UpdateSeenPath}";
         UpdateSeenBody body = new()
         {
             SeenAt = DateTime.Now.ToUniversalTime().ToString("O")
@@ -52,7 +52,7 @@ public async Task<Result> UpdateSeenAsync(string accessToken, CancellationToken
     /// <inheritdoc/>
     public async Task<Result<int>> GetUnreadCountAsync(string accessToken, CancellationToken ct)
     {
-        var url = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.UnreadCountPath}";
+        var url = $"{_baseUrl}/{UrlConstants.UnreadCountPath}";
         HttpRequestMessage message = new(HttpMethod.Get, url);
         message.Headers.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
 
diff --git a/src/Bluesky.NET/ApiClients/BlueskyApiClient.Posts.cs b/src/Bluesky.NET/ApiClients/BlueskyApiClient.Posts.cs
index 5bcd2ee..2b15de0 100644
--- a/src/Bluesky.NET/ApiClients/BlueskyApiClient.Posts.cs
+++ b/src/Bluesky.NET/ApiClients/BlueskyApiClient.Posts.cs
@@ -22,7 +22,7 @@ public async Task<IReadOnlyList<FeedPost>> GetPostsAsync(string accessToken, IRe
             return [];
         }
 
-        var timelineUrl = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.PostsPath}?uris={string.Join(",", atUriList)}";
+        var timelineUrl = $"{_baseUrl}/{UrlConstants.PostsPath}?uris={string.Join(",", atUriList)}";
         HttpRequestMessage message = new(HttpMethod.Get, timelineUrl);
         message.Headers.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
 
@@ -48,7 +48,7 @@ public async Task<IReadOnlyList<FeedPost>> GetPostsAsync(string accessToken, IRe
     /// <inheritdoc/>
     public async Task<CreateRecordResponse?> SubmitPostAsync(string accessToken, string handle, SubmissionRecord record, RecordType recordType)
     {
-        var url = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.CreateRecordPath}";
+        var url = $"{_baseUrl}/{UrlConstants.CreateRecordPath}";
 
         CreateRecordBody body = new()
         {
@@ -91,7 +91,7 @@ public async Task<IReadOnlyList<FeedPost>> GetPostsAsync(string accessToken, IRe
     /// <inheritdoc/>
     public async Task SubmitPostUndoAsync(string accessToken, string handle, string rkey, RecordType recordType, CancellationToken cancellationToken)
     {
-        var url = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.DeleteRecordPath}";
+        var url = $"{_baseUrl}/{UrlConstants.DeleteRecordPath}";
 
         DeleteRecordBody body = new()
         {
diff --git a/src/Bluesky.NET/ApiClients/BlueskyApiClient.Preferences.cs b/src/Bluesky.NET/ApiClients/BlueskyApiClient.Preferences.cs
index 582c0ea..7a0b683 100644
--- a/src/Bluesky.NET/ApiClients/BlueskyApiClient.Preferences.cs
+++ b/src/Bluesky.NET/ApiClients/BlueskyApiClient.Preferences.cs
@@ -21,7 +21,7 @@ public async Task<Result<IReadOnlyList<PreferenceItem>>> GetPreferencesAsync(str
     {
         ct.ThrowIfCancellationRequested();
 
-        var url = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.PreferencesPath}";
+        var url = $"{_baseUrl}/{UrlConstants.PreferencesPath}";
         HttpRequestMessage message = new(HttpMethod.Get, url);
         message.Headers.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
 
diff --git a/src/Bluesky.NET/ApiClients/BlueskyApiClient.Search.cs b/src/Bluesky.NET/ApiClients/BlueskyApiClient.Search.cs
index 8a471d9..195c1c1 100644
--- a/src/Bluesky.NET/ApiClients/BlueskyApiClient.Search.cs
+++ b/src/Bluesky.NET/ApiClients/BlueskyApiClient.Search.cs
@@ -20,7 +20,7 @@ public async Task<Result<FeedResponse>> SearchFeedsAsync(
         CancellationToken ct,
         string? cursor = null)
     {
-        var url = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.SearchFeedsPath}?query={HttpUtility.UrlEncode(query)}";
+        var url = $"{_baseUrl}/{UrlConstants.SearchFeedsPath}?query={HttpUtility.UrlEncode(query)}";
 
         if (cursor is not null)
         {
@@ -44,7 +44,7 @@ public async Task<Result<FeedResponse>> SearchActorsAsync(
         string? cursor = null)
     {
         // Ref: https://docs.bsky.app/docs/api/app-bsky-actor-search-actors
-        var url = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.SearchActorsPath}?q={HttpUtility.UrlEncode(query)}";
+        var url = $"{_baseUrl}/{UrlConstants.SearchActorsPath}?q={HttpUtility.UrlEncode(query)}";
 
         if (cursor is not null)
         {
@@ -70,7 +70,7 @@ public async Task<Result<FeedResponse>> SearchActorsAsync(
         // Ref: https://docs.bsky.app/docs/api/app-bsky-feed-search-posts
         options ??= new();
 
-        var url = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.SearchPostsPath}?q={HttpUtility.UrlEncode(query)}";
+        var url = $"{_baseUrl}/{UrlConstants.SearchPostsPath}?q={HttpUtility.UrlEncode(query)}";
 
         if (cursor is not null)
         {
diff --git a/src/Bluesky.NET/ApiClients/BlueskyApiClient.cs b/src/Bluesky.NET/ApiClients/BlueskyApiClient.cs
index c55773d..8e7cf02 100644
--- a/src/Bluesky.NET/ApiClients/BlueskyApiClient.cs
+++ b/src/Bluesky.NET/ApiClients/BlueskyApiClient.cs
@@ -16,19 +16,22 @@ namespace Bluesky.NET.ApiClients;
 public partial class BlueskyApiClient : IBlueskyApiClient
 {
     private readonly HttpClient _httpClient = new();
+    private string _baseUrl = "https://bsky.social";
 
-    public async Task<Result<AuthResponse>> RefreshAsync(string refreshToken)
+    public async Task<Result<AuthResponse>> RefreshAsync(string refreshToken, string baseUrl = UrlConstants.BlueskyBaseUrl)
     {
-        var refreshUrl = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.RefreshAuthPath}";
+        _baseUrl = baseUrl;
+        var refreshUrl = $"{baseUrl}/{UrlConstants.RefreshAuthPath}";
         HttpRequestMessage message = new(HttpMethod.Post, refreshUrl);
         message.Headers.Authorization = new AuthenticationHeaderValue("Bearer", refreshToken);
         return await PostAuthMessageAsync(message);
     }
 
     /// <inheritdoc/>
-    public async Task<Result<AuthResponse>> AuthenticateAsync(string identifer, string appPassword)
+    public async Task<Result<AuthResponse>> AuthenticateAsync(string identifer, string appPassword, string baseUrl = UrlConstants.BlueskyBaseUrl)
     {
-        var authUrl = $"{UrlConstants.BlueskyBaseUrl}/{UrlConstants.AuthPath}";
+        _baseUrl = baseUrl;
+        var authUrl = $"{baseUrl}/{UrlConstants.AuthPath}";
 
         var requestBody = new AuthRequestBody
         {
diff --git a/src/Bluesky.NET/ApiClients/IBlueskyApiClient.cs b/src/Bluesky.NET/ApiClients/IBlueskyApiClient.cs
index 58f3272..6fb9cc4 100644
--- a/src/Bluesky.NET/ApiClients/IBlueskyApiClient.cs
+++ b/src/Bluesky.NET/ApiClients/IBlueskyApiClient.cs
@@ -16,9 +16,9 @@ public interface IBlueskyApiClient
     /// <param name="userHandle">The user's handle or email address or DID.</param>
     /// <param name="appPassword">An app password provided by the user.</param>
     /// <returns>An <see cref="AuthResponse"/>.</returns>
-    Task<Result<AuthResponse>> AuthenticateAsync(string identifier, string appPassword);
+    Task<Result<AuthResponse>> AuthenticateAsync(string identifier, string appPassword, string baseUrl = UrlConstants.BlueskyBaseUrl);
     Task<FeedResponse> GetTimelineAsync(string accesstoken, string? cursor = null);
-    Task<Result<AuthResponse>> RefreshAsync(string refreshToken);
+    Task<Result<AuthResponse>> RefreshAsync(string refreshToken, string baseUrl = UrlConstants.BlueskyBaseUrl);
 
     Task<Author?> GetAuthorAsync(string accessToken, string identifier);
 
diff --git a/src/BlueskyClient.Uwp/Strings/en-US/Resources.resw b/src/BlueskyClient.Uwp/Strings/en-US/Resources.resw
index 29ba7f2..6c63f79 100644
--- a/src/BlueskyClient.Uwp/Strings/en-US/Resources.resw
+++ b/src/BlueskyClient.Uwp/Strings/en-US/Resources.resw
@@ -117,6 +117,9 @@
   <resheader name="writer">
     <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
   </resheader>
+  <data name="AdvancedText" xml:space="preserve">
+    <value>Advanced</value>
+  </data>
   <data name="AppPasswordHelpText" xml:space="preserve">
     <value>What's an App Password?</value>
   </data>
@@ -192,6 +195,9 @@
   <data name="PasswordBoxPlaceholder" xml:space="preserve">
     <value>Your special App Password</value>
   </data>
+  <data name="PDSBoxPlaceholder" xml:space="preserve">
+    <value>Custom PDS URL</value>
+  </data>
   <data name="PeopleText" xml:space="preserve">
     <value>People</value>
   </data>
diff --git a/src/BlueskyClient.Uwp/Views/SignInPage.xaml b/src/BlueskyClient.Uwp/Views/SignInPage.xaml
index 2345347..2ff8770 100644
--- a/src/BlueskyClient.Uwp/Views/SignInPage.xaml
+++ b/src/BlueskyClient.Uwp/Views/SignInPage.xaml
@@ -63,6 +63,27 @@
                     Command="{x:Bind ViewModel.SignInCommand}"
                     Content="{x:Bind strings:Resources.SignInText}"
                     IsEnabled="{x:Bind ex:UIExtensions.Not(ViewModel.SigningIn), Mode=OneWay}" />
+
+                <winui:Expander Header="{x:Bind strings:Resources.AdvancedText}"
+                                HorizontalAlignment="Stretch"
+                                HorizontalContentAlignment="Stretch"
+                                Margin="0,8,0,0">
+                    <StackPanel Orientation="Vertical">
+                        <TextBlock
+                            x:Name="PDSHeader"
+                            FontSize="12"
+                            Foreground="{ThemeResource TextFillColorTertiaryBrush}"
+                            Text="{x:Bind strings:Resources.PDSBoxPlaceholder}"
+                            TextWrapping="WrapWholeWords" />
+                        <TextBox
+                            Margin="0,4,0,0"
+                            AutomationProperties.LabeledBy="{x:Bind IdentifierHeader}"
+                            IsEnabled="{x:Bind ex:UIExtensions.Not(ViewModel.SigningIn), Mode=OneWay}"
+                            IsSpellCheckEnabled="False"
+                            PlaceholderText="https://bsky.social"
+                            Text="{x:Bind ViewModel.PdsInput, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
+                    </StackPanel>
+                </winui:Expander>
             </StackPanel>
 
             <winui:InfoBar
diff --git a/src/BlueskyClient/Services/AuthenticationService.cs b/src/BlueskyClient/Services/AuthenticationService.cs
index a2d1263..17b593c 100644
--- a/src/BlueskyClient/Services/AuthenticationService.cs
+++ b/src/BlueskyClient/Services/AuthenticationService.cs
@@ -1,4 +1,5 @@
 using Bluesky.NET.ApiClients;
+using Bluesky.NET.Constants;
 using Bluesky.NET.Models;
 using BlueskyClient.Constants;
 using FluentResults;
@@ -53,7 +54,7 @@ public async Task<Result<AuthResponse>> TrySilentSignInAsync()
         string? storedAppPassword = _secureCredentialStorage.GetCredential(AppPasswordCredentialKey(storedDid));
         if (storedAppPassword is { Length: > 0 })
         {
-            result = await SignInWithValidatedCredentialsAsync(storedDid, storedAppPassword);
+            result = await SignInWithValidatedCredentialsAsync(storedDid, storedAppPassword, _secureCredentialStorage.GetCredential(BaseURLCredentialKey(storedDid)));
         }
 
         return result;
@@ -67,6 +68,7 @@ public void SignOut()
         {
             _secureCredentialStorage.SetCredential(storedDid, string.Empty);
             _secureCredentialStorage.SetCredential(AppPasswordCredentialKey(storedDid), string.Empty);
+            _secureCredentialStorage.SetCredential(BaseURLCredentialKey(storedDid), string.Empty);
         }
 
         _userSettings.Set(UserSettingsConstants.LocalUserIdKey, string.Empty);
@@ -77,7 +79,7 @@ public void SignOut()
     }
 
     /// <inheritdoc/>
-    public async Task<Result<AuthResponse>> SignInAsync(string rawUserHandleOrEmail, string rawPassword)
+    public async Task<Result<AuthResponse>> SignInAsync(string rawUserHandleOrEmail, string rawPassword, string? baseUrl)
     {
         var userHandleOrEmail = rawUserHandleOrEmail.Trim().TrimStart('@');
         var password = rawPassword.Trim();
@@ -87,7 +89,7 @@ public async Task<Result<AuthResponse>> SignInAsync(string rawUserHandleOrEmail,
             return Result.Fail<AuthResponse>("Empty identifier or password");
         }
 
-        return await SignInWithValidatedCredentialsAsync(userHandleOrEmail, password);
+        return await SignInWithValidatedCredentialsAsync(userHandleOrEmail, password, baseUrl ?? "bsky.social");
     }
 
     public async Task<Result<string>> TryGetFreshTokenAsync()
@@ -142,9 +144,9 @@ private void UpdateStoredToken(AuthResponse response)
         }
     }
 
-    private async Task<Result<AuthResponse>> SignInWithValidatedCredentialsAsync(string identifier, string password)
+    private async Task<Result<AuthResponse>> SignInWithValidatedCredentialsAsync(string identifier, string password, string? baseUrl)
     {
-        Result<AuthResponse> result = await _apiClient.AuthenticateAsync(identifier, password);
+        Result<AuthResponse> result = await _apiClient.AuthenticateAsync(identifier, password, baseUrl ?? "bsky.social");
 
         if (result.IsSuccess)
         {
@@ -154,6 +156,9 @@ private async Task<Result<AuthResponse>> SignInWithValidatedCredentialsAsync(str
             {
                 _userSettings.Set(UserSettingsConstants.SignedInDIDKey, did);
                 _secureCredentialStorage.SetCredential(AppPasswordCredentialKey(did), password);
+                _secureCredentialStorage.SetCredential(
+                    BaseURLCredentialKey(did),
+                    baseUrl ?? UrlConstants.BlueskyBaseUrl);
             }
         }
 
@@ -162,4 +167,5 @@ private async Task<Result<AuthResponse>> SignInWithValidatedCredentialsAsync(str
 
 
     private static string AppPasswordCredentialKey(string did) => $"{did}-appPassword";
+    private static string BaseURLCredentialKey(string did) => $"{did}-baseUrl";
 }
diff --git a/src/BlueskyClient/Services/IAuthenticationService.cs b/src/BlueskyClient/Services/IAuthenticationService.cs
index 89b47b8..7811ee2 100644
--- a/src/BlueskyClient/Services/IAuthenticationService.cs
+++ b/src/BlueskyClient/Services/IAuthenticationService.cs
@@ -6,7 +6,7 @@ namespace BlueskyClient.Services;
 
 public interface IAuthenticationService
 {
-    Task<Result<AuthResponse>> SignInAsync(string rawUserHandle, string rawPassword);
+    Task<Result<AuthResponse>> SignInAsync(string rawUserHandle, string rawPassword, string? baseUrl);
     void SignOut();
     Task<Result<string>> TryGetFreshTokenAsync();
     Task<Result<AuthResponse>> TrySilentSignInAsync();
diff --git a/src/BlueskyClient/ViewModels/SignInPageViewModel.cs b/src/BlueskyClient/ViewModels/SignInPageViewModel.cs
index 22e0b7b..d0fef03 100644
--- a/src/BlueskyClient/ViewModels/SignInPageViewModel.cs
+++ b/src/BlueskyClient/ViewModels/SignInPageViewModel.cs
@@ -43,6 +43,9 @@ public SignInPageViewModel(
     [ObservableProperty]
     private string _appPasswordInput = string.Empty;
 
+    [ObservableProperty]
+    private string _pdsInput = "bsky.social";
+
     [ObservableProperty]
     [NotifyPropertyChangedFor(nameof(ErrorBannerVisible))]
     private string _signInErrorMessage = string.Empty;
@@ -56,7 +59,7 @@ private async Task SignInAsync()
 
         _telemetry.TrackEvent(TelemetryConstants.SignInClicked);
 
-        Result<AuthResponse> result = await _authService.SignInAsync(UserHandleInput, AppPasswordInput);
+        Result<AuthResponse> result = await _authService.SignInAsync(UserHandleInput, AppPasswordInput, PdsInput.Contains("://") ? PdsInput : $"https://{PdsInput}");
 
         SignInErrorMessage = result.IsSuccess
             ? string.Empty