From 1014563c754ba7a906e323ae5864019827427b5e Mon Sep 17 00:00:00 2001
From: Federico Maccaroni <fedemkr@gmail.com>
Date: Tue, 27 Jun 2023 18:49:38 -0300
Subject: [PATCH] [PM-192] Refactor forwarded email providers (#2579)

* PM-192 Refactor Forwarded email providers to use better patterns and code reuse.

* PM-192 fix format
---
 src/App/Pages/Generator/GeneratorPage.xaml    | 112 +-------
 .../Pages/Generator/GeneratorPageViewModel.cs | 253 ++++++++----------
 src/App/Resources/AppResources.Designer.cs    |  18 ++
 src/App/Resources/AppResources.resx           |   6 +
 src/Core/Abstractions/IApiService.cs          |   6 +-
 src/Core/Abstractions/ICryptoService.cs       |   1 +
 src/Core/Core.csproj                          |   2 +
 .../ForwardedEmailInvalidSecretException.cs   |  11 +
 .../Domain/UsernameGenerationOptions.cs       |  29 ++
 .../Models/Domain/UsernameGeneratorConfig.cs  |   9 -
 src/Core/Services/ApiService.cs               | 150 ++---------
 src/Core/Services/CryptoService.cs            |  18 ++
 .../EmailForwarders/AnonAddyForwarder.cs      |  42 +++
 .../Services/EmailForwarders/BaseForwarder.cs |  63 +++++
 .../EmailForwarders/DuckDuckGoForwarder.cs    |  25 ++
 .../EmailForwarders/FastmailForwarder.cs      |  98 +++++++
 .../EmailForwarders/FirefoxRelayForwarder.cs  |  36 +++
 .../EmailForwarders/ForwarderOptions.cs       |   7 +
 .../EmailForwarders/SimpleLoginForwarder.cs   |  25 ++
 .../Services/UsernameGenerationService.cs     |  95 ++-----
 20 files changed, 547 insertions(+), 459 deletions(-)
 create mode 100644 src/Core/Exceptions/ForwardedEmailInvalidSecretException.cs
 delete mode 100644 src/Core/Models/Domain/UsernameGeneratorConfig.cs
 create mode 100644 src/Core/Services/EmailForwarders/AnonAddyForwarder.cs
 create mode 100644 src/Core/Services/EmailForwarders/BaseForwarder.cs
 create mode 100644 src/Core/Services/EmailForwarders/DuckDuckGoForwarder.cs
 create mode 100644 src/Core/Services/EmailForwarders/FastmailForwarder.cs
 create mode 100644 src/Core/Services/EmailForwarders/FirefoxRelayForwarder.cs
 create mode 100644 src/Core/Services/EmailForwarders/ForwarderOptions.cs
 create mode 100644 src/Core/Services/EmailForwarders/SimpleLoginForwarder.cs

diff --git a/src/App/Pages/Generator/GeneratorPage.xaml b/src/App/Pages/Generator/GeneratorPage.xaml
index 53553cc3f..a2f8b533b 100644
--- a/src/App/Pages/Generator/GeneratorPage.xaml
+++ b/src/App/Pages/Generator/GeneratorPage.xaml
@@ -249,27 +249,25 @@
                             ItemDisplayBinding="{Binding ., Converter={StaticResource localizableEnum}}"
                             StyleClass="box-value"
                             AutomationId="ServiceTypePicker" />
-                        <!--ANONADDY OPTIONS-->
-                        <Grid IsVisible="{Binding ForwardedEmailServiceSelected, Converter={StaticResource enumToBool}, ConverterParameter={x:Static enums:ForwardedEmailServiceType.AnonAddy}}"
-                              Grid.RowDefinitions="Auto,*"
-                              Grid.ColumnDefinitions="*,Auto">
+                        <Grid 
+                            Grid.RowDefinitions="Auto,*"
+                            Grid.ColumnDefinitions="*,Auto">
                             <Label
                                 Margin="0,10,0,0"
-                                Text="{u:I18n APIAccessToken}"
+                                Text="{Binding ForwardedEmailApiSecretLabel}"
                                 StyleClass="box-label"/>
                             <Entry
-                                x:Name="_anonAddyApiAccessTokenEntry"
-                                Text="{Binding AnonAddyApiAccessToken}"
-                                IsPassword="{Binding ShowAnonAddyApiAccessToken, Converter={StaticResource inverseBool}}"
+                                Text="{Binding ForwardedEmailApiSecret}"
+                                IsPassword="{Binding ShowForwardedEmailApiSecret, Converter={StaticResource inverseBool}}"
                                 Grid.Row="1"
-                                AutomationId="AnonAddyApiAccessTokenEntry" />
+                                AutomationId="ForwardedEmailApiSecretEntry" />
                             <controls:IconButton
                                 StyleClass="box-row-button, box-row-button-platform"
-                                Text="{Binding ShowAnonAddyApiAccessToken, Converter={StaticResource inverseBool, iconGlyphConverter}, ConverterParameter={x:Static u:BooleanGlyphType.Eye}}"
+                                Text="{Binding ShowForwardedEmailApiSecret, Converter={StaticResource inverseBool, iconGlyphConverter}, ConverterParameter={x:Static u:BooleanGlyphType.Eye}}"
                                 Command="{Binding ToggleForwardedEmailHiddenValueCommand}"
                                 Grid.Row="1"
                                 Grid.Column="1"
-                                AutomationId="ShowAnonAddyApiAccessTokenButton" />
+                                AutomationId="ShowForwardedEmailApiSecretButton" />
                         </Grid>
                         <Label IsVisible="{Binding ForwardedEmailServiceSelected, Converter={StaticResource enumToBool}, ConverterParameter={x:Static enums:ForwardedEmailServiceType.AnonAddy}}"
                             Text="{u:I18n DomainNameRequiredParenthesis}"
@@ -280,98 +278,6 @@
                             Text="{Binding AnonAddyDomainName}"
                             StyleClass="box-value"
                             AutomationId="AnonAddyDomainNameEntry" />
-                        <!--FIREFOX RELAY OPTIONS-->
-                        <Grid StyleClass="box-row, box-row-input"
-                              IsVisible="{Binding ForwardedEmailServiceSelected, Converter={StaticResource enumToBool}, ConverterParameter={x:Static enums:ForwardedEmailServiceType.FirefoxRelay}}"
-                              Grid.RowDefinitions="Auto,*"
-                              Grid.ColumnDefinitions="*,Auto">
-                            <Label
-                                Text="{u:I18n APIAccessToken}"
-                                StyleClass="box-label"/>
-                            <Entry
-                                x:Name="_firefoxRelayApiAccessTokenEntry"
-                                Text="{Binding FirefoxRelayApiAccessToken}"
-                                StyleClass="box-value"
-                                Grid.Row="1"
-                                IsPassword="{Binding ShowFirefoxRelayApiAccessToken, Converter={StaticResource inverseBool}}"
-                                AutomationId="FirefoxRelayApiAccessTokenEntry" />
-                            <controls:IconButton
-                                StyleClass="box-row-button, box-row-button-platform"
-                                Text="{Binding ShowFirefoxRelayApiAccessToken, Converter={StaticResource inverseBool, iconGlyphConverter}, ConverterParameter={x:Static u:BooleanGlyphType.Eye}}"
-                                Command="{Binding ToggleForwardedEmailHiddenValueCommand}"
-                                Grid.Row="1"
-                                Grid.Column="1"
-                                AutomationId="ShowFirefoxRelayApiAccessTokenButton" />
-                        </Grid>
-                        <!--SIMPLELOGIN OPTIONS-->
-                        <Grid StyleClass="box-row, box-row-input"
-                              IsVisible="{Binding ForwardedEmailServiceSelected, Converter={StaticResource enumToBool}, ConverterParameter={x:Static enums:ForwardedEmailServiceType.SimpleLogin}}"
-                              Grid.RowDefinitions="Auto,*"
-                              Grid.ColumnDefinitions="*,Auto">
-                            <Label
-                                Text="{u:I18n APIKeyRequiredParenthesis}"
-                                StyleClass="box-label"/>
-                            <Entry
-                                x:Name="_simpleLoginApiKeyEntry"
-                                Text="{Binding SimpleLoginApiKey}"
-                                StyleClass="box-value" 
-                                Grid.Row="1"
-                                IsPassword="{Binding ShowSimpleLoginApiKey, Converter={StaticResource inverseBool}}"
-                                AutomationId="SimpleLoginApiKeyEntry" />
-                            <controls:IconButton 
-                                StyleClass="box-row-button, box-row-button-platform"
-                                Text="{Binding ShowSimpleLoginApiKey, Converter={StaticResource inverseBool, iconGlyphConverter}, ConverterParameter={x:Static u:BooleanGlyphType.Eye}}"
-                                Command="{Binding ToggleForwardedEmailHiddenValueCommand}"
-                                Grid.Row="1"
-                                Grid.Column="1"
-                                AutomationId="ShowSimpleLoginApiKeyButton" />
-                        </Grid>
-                        <!--DUCKDUCKGO OPTIONS-->
-                        <Grid StyleClass="box-row, box-row-input"
-                              IsVisible="{Binding ForwardedEmailServiceSelected, Converter={StaticResource enumToBool}, ConverterParameter={x:Static enums:ForwardedEmailServiceType.DuckDuckGo}}"
-                              Grid.RowDefinitions="Auto,*"
-                              Grid.ColumnDefinitions="*,Auto">
-                            <Label
-                                Text="{u:I18n APIKeyRequiredParenthesis}"
-                                StyleClass="box-label"/>
-                            <Entry
-                                x:Name="_duckDuckGoApiAccessTokenEntry"
-                                Text="{Binding DuckDuckGoApiKey}"
-                                StyleClass="box-value"
-                                Grid.Row="1"
-                                IsPassword="{Binding ShowDuckDuckGoApiKey, Converter={StaticResource inverseBool}}"
-                                AutomationId="DuckDuckGoApiKeyEntry" />
-                            <controls:IconButton
-                                StyleClass="box-row-button, box-row-button-platform"
-                                Text="{Binding ShowDuckDuckGoApiKey, Converter={StaticResource inverseBool, iconGlyphConverter}, ConverterParameter={x:Static u:BooleanGlyphType.Eye}}"
-                                Command="{Binding ToggleForwardedEmailHiddenValueCommand}"
-                                Grid.Row="1"
-                                Grid.Column="1"
-                                AutomationId="ShowDuckDuckGoApiKeyButton" />
-                        </Grid>
-                        <!--FASTMAIL OPTIONS-->
-                        <Grid StyleClass="box-row, box-row-input"
-                              IsVisible="{Binding ForwardedEmailServiceSelected, Converter={StaticResource enumToBool}, ConverterParameter={x:Static enums:ForwardedEmailServiceType.Fastmail}}"
-                              Grid.RowDefinitions="Auto,*"
-                              Grid.ColumnDefinitions="*,Auto">
-                            <Label
-                                Text="{u:I18n APIKeyRequiredParenthesis}"
-                                StyleClass="box-label"/>
-                            <Entry
-                                x:Name="_fastmailApiAccessTokenEntry"
-                                Text="{Binding FastmailApiKey}"
-                                StyleClass="box-value"
-                                Grid.Row="1"
-                                IsPassword="{Binding ShowFastmailApiKey, Converter={StaticResource inverseBool}}"
-                                AutomationId="FastmailApiKeyEntry" />
-                            <controls:IconButton
-                                StyleClass="box-row-button, box-row-button-platform"
-                                Text="{Binding ShowFastmailApiKey, Converter={StaticResource iconGlyphConverter}, ConverterParameter={x:Static u:BooleanGlyphType.Eye}}"
-                                Command="{Binding ToggleForwardedEmailHiddenValueCommand}"
-                                Grid.Row="1"
-                                Grid.Column="1"
-                                AutomationId="ShowFastmailApiKeyButton" />
-                        </Grid>
                     </StackLayout>                    
                     <!--RANDOM WORD OPTIONS-->
                     <Grid IsVisible="{Binding UsernameTypeSelected, Converter={StaticResource enumToBool}, ConverterParameter={x:Static enums:UsernameType.RandomWord}}">
diff --git a/src/App/Pages/Generator/GeneratorPageViewModel.cs b/src/App/Pages/Generator/GeneratorPageViewModel.cs
index 78436352b..935a9f7e0 100644
--- a/src/App/Pages/Generator/GeneratorPageViewModel.cs
+++ b/src/App/Pages/Generator/GeneratorPageViewModel.cs
@@ -8,6 +8,7 @@ using Bit.App.Utilities;
 using Bit.Core;
 using Bit.Core.Abstractions;
 using Bit.Core.Enums;
+using Bit.Core.Exceptions;
 using Bit.Core.Models.Domain;
 using Bit.Core.Utilities;
 using Xamarin.CommunityToolkit.ObjectModel;
@@ -23,7 +24,7 @@ namespace Bit.App.Pages
         private readonly IUsernameGenerationService _usernameGenerationService;
         private readonly ITokenService _tokenService;
         private readonly IDeviceActionService _deviceActionService;
-        readonly LazyResolve<ILogger> _logger = new LazyResolve<ILogger>("logger");
+        readonly LazyResolve<ILogger> _logger = new LazyResolve<ILogger>();
 
         private PasswordGenerationOptions _options;
         private UsernameGenerationOptions _usernameOptions;
@@ -49,11 +50,7 @@ namespace Bit.App.Pages
         private bool _doneIniting;
         private bool _showTypePicker;
         private string _emailWebsite;
-        private bool _showFirefoxRelayApiAccessToken;
-        private bool _showAnonAddyApiAccessToken;
-        private bool _showSimpleLoginApiKey;
-        private bool _showDuckDuckGoApiKey;
-        private bool _showFastmailApiKey;
+        private bool _showForwardedEmailApiSecret;
         private bool _editMode;
 
         public GeneratorPageViewModel()
@@ -96,7 +93,7 @@ namespace Bit.App.Pages
             UsernameTypePromptHelpCommand = new Command(UsernameTypePromptHelp);
             RegenerateCommand = new AsyncCommand(RegenerateAsync, onException: ex => OnSubmitException(ex), allowsMultipleExecutions: false);
             RegenerateUsernameCommand = new AsyncCommand(RegenerateUsernameAsync, onException: ex => OnSubmitException(ex), allowsMultipleExecutions: false);
-            ToggleForwardedEmailHiddenValueCommand = new AsyncCommand(ToggleForwardedEmailHiddenValueAsync, onException: ex => _logger.Value.Exception(ex), allowsMultipleExecutions: false);
+            ToggleForwardedEmailHiddenValueCommand = new Command(() => ShowForwardedEmailApiSecret = !ShowForwardedEmailApiSecret);
             CopyCommand = new AsyncCommand(CopyAsync, onException: ex => _logger.Value.Exception(ex), allowsMultipleExecutions: false);
             CloseCommand = new AsyncCommand(CloseAsync, onException: ex => _logger.Value.Exception(ex), allowsMultipleExecutions: false);
         }
@@ -415,7 +412,6 @@ namespace Bit.App.Pages
 
         public string UsernameTypeDescriptionLabel => GetUsernameTypeLabelDescription(UsernameTypeSelected);
 
-
         public ForwardedEmailServiceType ForwardedEmailServiceSelected
         {
             get => _usernameOptions.ServiceType;
@@ -425,7 +421,11 @@ namespace Bit.App.Pages
                 {
                     _usernameOptions.ServiceType = value;
                     Username = Constants.DefaultUsernameGenerated;
-                    TriggerPropertyChanged(nameof(ForwardedEmailServiceSelected));
+                    TriggerPropertyChanged(nameof(ForwardedEmailServiceSelected), new string[]
+                    {
+                        nameof(ForwardedEmailApiSecret),
+                        nameof(ForwardedEmailApiSecretLabel)
+                    });
                     SaveUsernameOptionsAsync(false).FireAndForget();
                 }
             }
@@ -445,27 +445,104 @@ namespace Bit.App.Pages
             }
         }
 
-        public string AnonAddyApiAccessToken
+        public string ForwardedEmailApiSecret
         {
-            get => _usernameOptions.AnonAddyApiAccessToken;
+            get
+            {
+                switch (ForwardedEmailServiceSelected)
+                {
+                    case ForwardedEmailServiceType.AnonAddy:
+                        return _usernameOptions.AnonAddyApiAccessToken;
+                    case ForwardedEmailServiceType.DuckDuckGo:
+                        return _usernameOptions.DuckDuckGoApiKey;
+                    case ForwardedEmailServiceType.Fastmail:
+                        return _usernameOptions.FastMailApiKey;
+                    case ForwardedEmailServiceType.FirefoxRelay:
+                        return _usernameOptions.FirefoxRelayApiAccessToken;
+                    case ForwardedEmailServiceType.SimpleLogin:
+                        return _usernameOptions.SimpleLoginApiKey;
+                    default:
+                        return null;
+                }
+            }
             set
             {
-                if (_usernameOptions.AnonAddyApiAccessToken != value)
+                bool changed = false;
+                switch (ForwardedEmailServiceSelected)
                 {
-                    _usernameOptions.AnonAddyApiAccessToken = value;
-                    TriggerPropertyChanged(nameof(AnonAddyApiAccessToken));
+                    case ForwardedEmailServiceType.AnonAddy:
+                        if (_usernameOptions.AnonAddyApiAccessToken != value)
+                        {
+                            _usernameOptions.AnonAddyApiAccessToken = value;
+                            changed = true;
+                        }
+                        break;
+                    case ForwardedEmailServiceType.DuckDuckGo:
+                        if (_usernameOptions.DuckDuckGoApiKey != value)
+                        {
+                            _usernameOptions.DuckDuckGoApiKey = value;
+                            changed = true;
+                        }
+                        break;
+                    case ForwardedEmailServiceType.Fastmail:
+                        if (_usernameOptions.FastMailApiKey != value)
+                        {
+                            _usernameOptions.FastMailApiKey = value;
+                            changed = true;
+                        }
+                        break;
+                    case ForwardedEmailServiceType.FirefoxRelay:
+                        if (_usernameOptions.FirefoxRelayApiAccessToken != value)
+                        {
+                            _usernameOptions.FirefoxRelayApiAccessToken = value;
+                            changed = true;
+                        }
+                        break;
+                    case ForwardedEmailServiceType.SimpleLogin:
+                        if (_usernameOptions.SimpleLoginApiKey != value)
+                        {
+                            _usernameOptions.SimpleLoginApiKey = value;
+                            changed = true;
+                        }
+                        break;
+                    default:
+                        break;
+                }
+
+                if (changed)
+                {
+                    TriggerPropertyChanged(nameof(ForwardedEmailApiSecret));
                     SaveUsernameOptionsAsync(false).FireAndForget();
                 }
             }
         }
 
-        public bool ShowAnonAddyApiAccessToken
+        public string ForwardedEmailApiSecretLabel
         {
             get
             {
-                return _showAnonAddyApiAccessToken;
+                switch (ForwardedEmailServiceSelected)
+                {
+                    case ForwardedEmailServiceType.AnonAddy:
+                    case ForwardedEmailServiceType.FirefoxRelay:
+                        return AppResources.APIAccessToken;
+                    case ForwardedEmailServiceType.DuckDuckGo:
+                    case ForwardedEmailServiceType.Fastmail:
+                    case ForwardedEmailServiceType.SimpleLogin:
+                        return AppResources.APIKeyRequiredParenthesis;
+                    default:
+                        return null;
+                }
             }
-            set => SetProperty(ref _showAnonAddyApiAccessToken, value);
+        }
+
+        public bool ShowForwardedEmailApiSecret
+        {
+            get
+            {
+                return _showForwardedEmailApiSecret;
+            }
+            set => SetProperty(ref _showForwardedEmailApiSecret, value);
         }
 
         public string AnonAddyDomainName
@@ -482,99 +559,6 @@ namespace Bit.App.Pages
             }
         }
 
-        public string FirefoxRelayApiAccessToken
-        {
-            get => _usernameOptions.FirefoxRelayApiAccessToken;
-            set
-            {
-                if (_usernameOptions.FirefoxRelayApiAccessToken != value)
-                {
-                    _usernameOptions.FirefoxRelayApiAccessToken = value;
-                    TriggerPropertyChanged(nameof(FirefoxRelayApiAccessToken));
-                    SaveUsernameOptionsAsync(false).FireAndForget();
-                }
-            }
-        }
-
-        public bool ShowFirefoxRelayApiAccessToken
-        {
-            get
-            {
-                return _showFirefoxRelayApiAccessToken;
-            }
-            set => SetProperty(ref _showFirefoxRelayApiAccessToken, value);
-        }
-
-        public string SimpleLoginApiKey
-        {
-            get => _usernameOptions.SimpleLoginApiKey;
-            set
-            {
-                if (_usernameOptions.SimpleLoginApiKey != value)
-                {
-                    _usernameOptions.SimpleLoginApiKey = value;
-                    TriggerPropertyChanged(nameof(SimpleLoginApiKey));
-                    SaveUsernameOptionsAsync(false).FireAndForget();
-                }
-            }
-        }
-
-        public bool ShowSimpleLoginApiKey
-        {
-            get
-            {
-                return _showSimpleLoginApiKey;
-            }
-            set => SetProperty(ref _showSimpleLoginApiKey, value);
-        }
-
-        public string DuckDuckGoApiKey
-        {
-            get => _usernameOptions.DuckDuckGoApiKey;
-            set
-            {
-                if (_usernameOptions.DuckDuckGoApiKey != value)
-                {
-                    _usernameOptions.DuckDuckGoApiKey = value;
-                    TriggerPropertyChanged(nameof(DuckDuckGoApiKey));
-                    SaveUsernameOptionsAsync(false).FireAndForget();
-                }
-            }
-        }
-
-        public bool ShowDuckDuckGoApiKey
-        {
-            get
-            {
-                return _showDuckDuckGoApiKey;
-            }
-            set => SetProperty(ref _showDuckDuckGoApiKey, value);
-        }
-
-
-        public string FastmailApiKey
-        {
-            get => _usernameOptions.FastMailApiKey;
-            set
-            {
-                if (_usernameOptions.FastMailApiKey != value)
-                {
-                    _usernameOptions.FastMailApiKey = value;
-                    TriggerPropertyChanged(nameof(FastmailApiKey));
-                    SaveUsernameOptionsAsync(false).FireAndForget();
-                }
-            }
-        }
-
-        public bool ShowFastmailApiKey
-        {
-            get
-            {
-                return _showFastmailApiKey;
-            }
-            set => SetProperty(ref _showFastmailApiKey, value);
-        }
-
         public bool CapitalizeRandomWordUsername
         {
             get => _usernameOptions.CapitalizeRandomWordUsername;
@@ -807,12 +791,9 @@ namespace Bit.App.Pages
             TriggerPropertyChanged(nameof(PlusAddressedEmailTypeSelected));
             TriggerPropertyChanged(nameof(IncludeNumberRandomWordUsername));
             TriggerPropertyChanged(nameof(CapitalizeRandomWordUsername));
-            TriggerPropertyChanged(nameof(SimpleLoginApiKey));
-            TriggerPropertyChanged(nameof(FirefoxRelayApiAccessToken));
+            TriggerPropertyChanged(nameof(ForwardedEmailApiSecret));
+            TriggerPropertyChanged(nameof(ForwardedEmailApiSecretLabel));
             TriggerPropertyChanged(nameof(AnonAddyDomainName));
-            TriggerPropertyChanged(nameof(AnonAddyApiAccessToken));
-            TriggerPropertyChanged(nameof(DuckDuckGoApiKey));
-            TriggerPropertyChanged(nameof(FastmailApiKey));
             TriggerPropertyChanged(nameof(CatchAllEmailDomain));
             TriggerPropertyChanged(nameof(ForwardedEmailServiceSelected));
             TriggerPropertyChanged(nameof(UsernameTypeSelected));
@@ -845,15 +826,23 @@ namespace Bit.App.Pages
         {
             _logger.Value.Exception(ex);
 
+            string message = AppResources.GenericErrorMessage;
+
             if (IsUsername && UsernameTypeSelected == UsernameType.ForwardedEmailAlias)
             {
-                await Device.InvokeOnMainThreadAsync(() => Page.DisplayAlert(
-                    AppResources.AnErrorHasOccurred, string.Format(AppResources.UnknownXErrorMessage, ForwardedEmailServiceSelected), AppResources.Ok));
-            }
-            else
-            {
-                await Device.InvokeOnMainThreadAsync(() => Page.DisplayAlert(AppResources.AnErrorHasOccurred, AppResources.GenericErrorMessage, AppResources.Ok));
+                if (ex is ForwardedEmailInvalidSecretException)
+                {
+                    message = ForwardedEmailServiceSelected == ForwardedEmailServiceType.AnonAddy || ForwardedEmailServiceSelected == ForwardedEmailServiceType.FirefoxRelay
+                                ? AppResources.InvalidAPIToken
+                                : AppResources.InvalidAPIKey;
+                }
+                else
+                {
+                    message = string.Format(AppResources.UnknownXErrorMessage, ForwardedEmailServiceSelected);
+                }
             }
+
+            await Device.InvokeOnMainThreadAsync(() => Page.DisplayAlert(AppResources.AnErrorHasOccurred, message, AppResources.Ok));
         }
 
         private string GetUsernameTypeLabelDescription(UsernameType value)
@@ -870,27 +859,5 @@ namespace Bit.App.Pages
                     return string.Empty;
             }
         }
-
-        private async Task ToggleForwardedEmailHiddenValueAsync()
-        {
-            switch (ForwardedEmailServiceSelected)
-            {
-                case ForwardedEmailServiceType.AnonAddy:
-                    ShowAnonAddyApiAccessToken = !ShowAnonAddyApiAccessToken;
-                    break;
-                case ForwardedEmailServiceType.FirefoxRelay:
-                    ShowFirefoxRelayApiAccessToken = !ShowFirefoxRelayApiAccessToken;
-                    break;
-                case ForwardedEmailServiceType.SimpleLogin:
-                    ShowSimpleLoginApiKey = !ShowSimpleLoginApiKey;
-                    break;
-                case ForwardedEmailServiceType.DuckDuckGo:
-                    ShowDuckDuckGoApiKey = !ShowDuckDuckGoApiKey;
-                    break;
-                case ForwardedEmailServiceType.Fastmail:
-                    ShowFastmailApiKey = !ShowFastmailApiKey;
-                    break;
-            }
-        }
     }
 }
diff --git a/src/App/Resources/AppResources.Designer.cs b/src/App/Resources/AppResources.Designer.cs
index f4bf3ff61..82bb07c83 100644
--- a/src/App/Resources/AppResources.Designer.cs
+++ b/src/App/Resources/AppResources.Designer.cs
@@ -3262,6 +3262,24 @@ namespace Bit.App.Resources {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Invalid API key.
+        /// </summary>
+        public static string InvalidAPIKey {
+            get {
+                return ResourceManager.GetString("InvalidAPIKey", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Invalid API token.
+        /// </summary>
+        public static string InvalidAPIToken {
+            get {
+                return ResourceManager.GetString("InvalidAPIToken", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Invalid email address..
         /// </summary>
diff --git a/src/App/Resources/AppResources.resx b/src/App/Resources/AppResources.resx
index 8fa9d4375..9b10e05a3 100644
--- a/src/App/Resources/AppResources.resx
+++ b/src/App/Resources/AppResources.resx
@@ -2637,4 +2637,10 @@ Do you want to switch to this account?</value>
   <data name="UnlockingMayFailDueToInsufficientMemoryDecreaseYourKDFMemorySettingsToResolve" xml:space="preserve">
     <value>Unlocking may fail due to insufficient memory. Decrease your KDF memory settings to resolve.</value>
   </data>
+  <data name="InvalidAPIKey" xml:space="preserve">
+    <value>Invalid API key</value>
+  </data>
+  <data name="InvalidAPIToken" xml:space="preserve">
+    <value>Invalid API token</value>
+  </data>
 </root>
diff --git a/src/Core/Abstractions/IApiService.cs b/src/Core/Abstractions/IApiService.cs
index 0c2474439..b073b227c 100644
--- a/src/Core/Abstractions/IApiService.cs
+++ b/src/Core/Abstractions/IApiService.cs
@@ -1,8 +1,9 @@
 using System;
 using System.Collections.Generic;
+using System.Net;
 using System.Net.Http;
+using System.Threading;
 using System.Threading.Tasks;
-using Bit.Core.Enums;
 using Bit.Core.Models.Domain;
 using Bit.Core.Models.Request;
 using Bit.Core.Models.Response;
@@ -48,6 +49,7 @@ namespace Bit.Core.Abstractions
         Task<SsoPrevalidateResponse> PreValidateSso(string identifier);
         Task<TResponse> SendAsync<TRequest, TResponse>(HttpMethod method, string path,
             TRequest body, bool authed, bool hasResponse, Action<HttpRequestMessage> alterRequest, bool logoutOnUnauthorized = true);
+        Task<HttpResponseMessage> SendAsync(HttpRequestMessage requestMessage, CancellationToken cancellationToken = default);
         void SetUrls(EnvironmentUrls urls);
         [Obsolete("Mar 25 2021: This method has been deprecated in favor of direct uploads. This method still exists for backward compatibility with old server versions.")]
         Task<CipherResponse> PostCipherAttachmentLegacyAsync(string id, MultipartFormDataContent data);
@@ -89,9 +91,9 @@ namespace Bit.Core.Abstractions
         Task<PasswordlessLoginResponse> GetAuthResponseAsync(string id, string accessCode);
         Task<PasswordlessLoginResponse> PutAuthRequestAsync(string id, string key, string masterPasswordHash, string deviceIdentifier, bool requestApproved);
         Task<PasswordlessLoginResponse> PostCreateRequestAsync(PasswordlessCreateLoginRequest passwordlessCreateLoginRequest);
-        Task<string> GetUsernameFromAsync(ForwardedEmailServiceType service, UsernameGeneratorConfig config);
         Task<bool> GetKnownDeviceAsync(string email, string deviceIdentifier);
         Task<OrganizationDomainSsoDetailsResponse> GetOrgDomainSsoDetailsAsync(string email);
         Task<ConfigResponse> GetConfigsAsync();
+        Task<string> GetFastmailAccountIdAsync(string apiKey);
     }
 }
diff --git a/src/Core/Abstractions/ICryptoService.cs b/src/Core/Abstractions/ICryptoService.cs
index 60bbd3624..060cd9887 100644
--- a/src/Core/Abstractions/ICryptoService.cs
+++ b/src/Core/Abstractions/ICryptoService.cs
@@ -43,6 +43,7 @@ namespace Bit.Core.Abstractions
         Task<Tuple<EncString, SymmetricCryptoKey>> MakeShareKeyAsync();
         Task<SymmetricCryptoKey> MakeSendKeyAsync(byte[] keyMaterial);
         Task<int> RandomNumberAsync(int min, int max);
+        Task<string> RandomStringAsync(int length);
         Task<Tuple<SymmetricCryptoKey, EncString>> RemakeEncKeyAsync(SymmetricCryptoKey key);
         Task<EncString> RsaEncryptAsync(byte[] data, byte[] publicKey = null);
         Task<byte[]> RsaDecryptAsync(string encValue, byte[] privateKey = null);
diff --git a/src/Core/Core.csproj b/src/Core/Core.csproj
index 216e148d7..76c88095e 100644
--- a/src/Core/Core.csproj
+++ b/src/Core/Core.csproj
@@ -20,6 +20,7 @@
     <None Remove="Attributes\" />
     <None Remove="MessagePack" />
     <None Remove="MessagePack.MSBuild.Tasks" />
+    <None Remove="Services\EmailForwarders\" />
   </ItemGroup>
 
   <ItemGroup>
@@ -44,5 +45,6 @@
   <ItemGroup>
     <Folder Include="Services\Logging\" />
     <Folder Include="Attributes\" />
+    <Folder Include="Services\EmailForwarders\" />
   </ItemGroup>
 </Project>
diff --git a/src/Core/Exceptions/ForwardedEmailInvalidSecretException.cs b/src/Core/Exceptions/ForwardedEmailInvalidSecretException.cs
new file mode 100644
index 000000000..2871b60d2
--- /dev/null
+++ b/src/Core/Exceptions/ForwardedEmailInvalidSecretException.cs
@@ -0,0 +1,11 @@
+using System;
+namespace Bit.Core.Exceptions
+{
+    public class ForwardedEmailInvalidSecretException : Exception
+    {
+        public ForwardedEmailInvalidSecretException(Exception innerEx)
+            : base("Invalid API Secret", innerEx)
+        {
+        }
+    }
+}
diff --git a/src/Core/Models/Domain/UsernameGenerationOptions.cs b/src/Core/Models/Domain/UsernameGenerationOptions.cs
index 44c48a6f3..deb98521d 100644
--- a/src/Core/Models/Domain/UsernameGenerationOptions.cs
+++ b/src/Core/Models/Domain/UsernameGenerationOptions.cs
@@ -1,4 +1,5 @@
 using Bit.Core.Enums;
+using Bit.Core.Services.EmailForwarders;
 
 namespace Bit.Core.Models.Domain
 {
@@ -24,5 +25,33 @@ namespace Bit.Core.Models.Domain
         public string AnonAddyApiAccessToken { get; set; }
         public string AnonAddyDomainName { get; set; }
         public string EmailWebsite { get; set; }
+
+        public ForwarderOptions GetForwarderOptions()
+        {
+            if (Type != UsernameType.ForwardedEmailAlias)
+            {
+                return null;
+            }
+
+            switch (ServiceType)
+            {
+                case ForwardedEmailServiceType.AnonAddy:
+                    return new AnonAddyForwarderOptions
+                    {
+                        ApiKey = AnonAddyApiAccessToken,
+                        DomainName = AnonAddyDomainName
+                    };
+                case ForwardedEmailServiceType.DuckDuckGo:
+                    return new ForwarderOptions { ApiKey = DuckDuckGoApiKey };
+                case ForwardedEmailServiceType.Fastmail:
+                    return new ForwarderOptions { ApiKey = FastMailApiKey };
+                case ForwardedEmailServiceType.FirefoxRelay:
+                    return new ForwarderOptions { ApiKey = FirefoxRelayApiAccessToken };
+                case ForwardedEmailServiceType.SimpleLogin:
+                    return new ForwarderOptions { ApiKey = SimpleLoginApiKey };
+                default:
+                    return null;
+            }
+        }
     }
 }
diff --git a/src/Core/Models/Domain/UsernameGeneratorConfig.cs b/src/Core/Models/Domain/UsernameGeneratorConfig.cs
deleted file mode 100644
index 53de60310..000000000
--- a/src/Core/Models/Domain/UsernameGeneratorConfig.cs
+++ /dev/null
@@ -1,9 +0,0 @@
-namespace Bit.Core.Models.Domain
-{
-    public class UsernameGeneratorConfig
-    {
-        public string ApiToken { get; set; }
-        public string Domain { get; set; }
-        public string Url { get; set; }
-    }
-}
diff --git a/src/Core/Services/ApiService.cs b/src/Core/Services/ApiService.cs
index dde3b9505..6b2dbe48e 100644
--- a/src/Core/Services/ApiService.cs
+++ b/src/Core/Services/ApiService.cs
@@ -4,6 +4,7 @@ using System.Linq;
 using System.Net;
 using System.Net.Http;
 using System.Text;
+using System.Threading;
 using System.Threading.Tasks;
 using Bit.Core.Abstractions;
 using Bit.Core.Enums;
@@ -763,111 +764,29 @@ namespace Bit.Core.Services
             }
         }
 
-        public async Task<string> GetUsernameFromAsync(ForwardedEmailServiceType service, UsernameGeneratorConfig config)
+        public async Task<HttpResponseMessage> SendAsync(HttpRequestMessage requestMessage, CancellationToken cancellationToken = default)
         {
-            using (var requestMessage = new HttpRequestMessage())
+            HttpResponseMessage response;
+            try
             {
-                requestMessage.Version = new Version(1, 0);
-                requestMessage.Method = HttpMethod.Post;
-                requestMessage.RequestUri = new Uri(config.Url);
-                requestMessage.Headers.Add("Accept", "application/json");
-
-                switch (service)
-                {
-                    case ForwardedEmailServiceType.AnonAddy:
-                        requestMessage.Headers.Add("Authorization", $"Bearer {config.ApiToken}");
-                        requestMessage.Content = new FormUrlEncodedContent(new Dictionary<string, string>
-                        {
-                            ["domain"] = config.Domain
-                        });
-                        break;
-                    case ForwardedEmailServiceType.FirefoxRelay:
-                        requestMessage.Headers.Add("Authorization", $"Token {config.ApiToken}");
-                        requestMessage.Content = new StringContent(JsonConvert.SerializeObject(
-                            new
-                            {
-                                enabled = true,
-                                description = "Generated by Bitwarden."
-                            }), Encoding.UTF8, "application/json");
-                        break;
-                    case ForwardedEmailServiceType.SimpleLogin:
-                        requestMessage.Headers.Add("Authentication", config.ApiToken);
-                        break;
-                    case ForwardedEmailServiceType.DuckDuckGo:
-                        requestMessage.Headers.Add("Authorization", $"Bearer {config.ApiToken}");
-                        break;
-                    case ForwardedEmailServiceType.Fastmail:
-                        requestMessage.Headers.Add("Authorization", $"Bearer {config.ApiToken}");
-                        requestMessage.Content = new StringContent(await CreateFastmailRequest(config.ApiToken),
-                            Encoding.UTF8, "application/json");
-                        break;
-                }
-
-                HttpResponseMessage response;
-                try
-                {
-                    response = await _httpClient.SendAsync(requestMessage);
-                }
-                catch (Exception e)
-                {
-                    throw new ApiException(HandleWebError(e));
-                }
-                if (!response.IsSuccessStatusCode)
-                {
-                    throw new ApiException(new ErrorResponse
-                    {
-                        StatusCode = response.StatusCode,
-                        Message = $"{service} error: {(int)response.StatusCode} {response.ReasonPhrase}."
-                    });
-                }
-                var responseJsonString = await response.Content.ReadAsStringAsync();
-                var result = JObject.Parse(responseJsonString);
-
-                switch (service)
-                {
-                    case ForwardedEmailServiceType.AnonAddy:
-                        return result["data"]?["email"]?.ToString();
-                    case ForwardedEmailServiceType.FirefoxRelay:
-                        return result["full_address"]?.ToString();
-                    case ForwardedEmailServiceType.SimpleLogin:
-                        return result["alias"]?.ToString();
-                    case ForwardedEmailServiceType.DuckDuckGo:
-                        return $"{result["address"]?.ToString()}@duck.com";
-                    case ForwardedEmailServiceType.Fastmail:
-                        return HandleFastMailResponse(result);
-                    default:
-                        return string.Empty;
-                }
+                response = await _httpClient.SendAsync(requestMessage, cancellationToken);
             }
+            catch (Exception e)
+            {
+                throw new ApiException(HandleWebError(e));
+            }
+            if (!response.IsSuccessStatusCode)
+            {
+                throw new ApiException(new ErrorResponse
+                {
+                    StatusCode = response.StatusCode,
+                    Message = $"{requestMessage.RequestUri} error: {(int)response.StatusCode} {response.ReasonPhrase}."
+                });
+            }
+            return response;
         }
 
-        private string HandleFastMailResponse(JObject result)
-        {
-            if (result["methodResponses"] == null || !result["methodResponses"].HasValues ||
-                !result["methodResponses"][0].HasValues)
-            {
-                throw new Exception("Fastmail error: could not parse response.");
-            }
-            if (result["methodResponses"][0][0].ToString() == "MaskedEmail/set")
-            {
-                if (result["methodResponses"][0][1]?["created"]?["new-masked-email"] != null)
-                {
-                    return result["methodResponses"][0][1]?["created"]?["new-masked-email"]?["email"].ToString();
-                }
-                if (result["methodResponses"][0][1]?["notCreated"]?["new-masked-email"] != null)
-                {
-                    throw new Exception("Fastmail error: " +
-                                        result["methodResponses"][0][1]?["created"]?["new-masked-email"]?["description"].ToString());
-                }
-            }
-            else if (result["methodResponses"][0][0].ToString() == "error")
-            {
-                throw new Exception("Fastmail error: " + result["methodResponses"][0][1]?["description"].ToString());
-            }
-            throw new Exception("Fastmail error: could not parse response.");
-        }
-
-        private async Task<string> CreateFastmailRequest(string apiKey)
+        public async Task<string> GetFastmailAccountIdAsync(string apiKey)
         {
             using (var httpclient = new HttpClient())
             {
@@ -891,36 +810,7 @@ namespace Bit.Core.Services
                     });
                 }
                 var result = JObject.Parse(await response.Content.ReadAsStringAsync());
-                var accountId = result["primaryAccounts"]?["https://www.fastmail.com/dev/maskedemail"]?.ToString();
-                var requestJObj = new JObject
-                {
-                    new JProperty("using",
-                        new JArray { "https://www.fastmail.com/dev/maskedemail", "urn:ietf:params:jmap:core" }),
-                    new JProperty("methodCalls",
-                        new JArray
-                        {
-                            new JArray
-                            {
-                                "MaskedEmail/set",
-                                new JObject
-                                {
-                                    ["accountId"] = accountId,
-                                    ["create"] = new JObject
-                                    {
-                                        ["new-masked-email"] = new JObject
-                                        {
-                                            ["state"] = "enabled",
-                                            ["description"] = "",
-                                            ["url"] = "",
-                                            ["emailPrefix"] = ""
-                                        }
-                                    }
-                                },
-                                "0"
-                            }
-                        })
-                };
-                return requestJObj.ToString();
+                return result["primaryAccounts"]?["https://www.fastmail.com/dev/maskedemail"]?.ToString();
             }
         }
 
diff --git a/src/Core/Services/CryptoService.cs b/src/Core/Services/CryptoService.cs
index b8aaadb7d..bfa7c5b82 100644
--- a/src/Core/Services/CryptoService.cs
+++ b/src/Core/Services/CryptoService.cs
@@ -14,6 +14,8 @@ namespace Bit.Core.Services
 {
     public class CryptoService : ICryptoService
     {
+        private const string RANDOM_STRING_CHARSET = "abcdefghijklmnopqrstuvwxyz1234567890";
+
         private readonly IStateService _stateService;
         private readonly ICryptoFunctionService _cryptoFunctionService;
 
@@ -633,6 +635,22 @@ namespace Bit.Core.Services
             return (int)(min + (ui % diff));
         }
 
+        /// <summary>
+        /// Makes random string with length <paramref name="length"/> based on the charset <see cref="RANDOM_STRING_CHARSET"/>
+        /// </summary>
+        public async Task<string> RandomStringAsync(int length)
+        {
+            var sb = new StringBuilder();
+
+            for (var i = 0; i < length; i++)
+            {
+                var randomCharIndex = await RandomNumberAsync(0, RANDOM_STRING_CHARSET.Length - 1);
+                sb.Append(RANDOM_STRING_CHARSET[randomCharIndex]);
+            }
+
+            return sb.ToString();
+        }
+
         // Helpers
 
         private async Task<EncryptedObject> AesEncryptAsync(byte[] data, SymmetricCryptoKey key)
diff --git a/src/Core/Services/EmailForwarders/AnonAddyForwarder.cs b/src/Core/Services/EmailForwarders/AnonAddyForwarder.cs
new file mode 100644
index 000000000..834dd863d
--- /dev/null
+++ b/src/Core/Services/EmailForwarders/AnonAddyForwarder.cs
@@ -0,0 +1,42 @@
+using System.Collections.Generic;
+using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Threading.Tasks;
+using Bit.Core.Abstractions;
+using Newtonsoft.Json.Linq;
+
+namespace Bit.Core.Services.EmailForwarders
+{
+    public class AnonAddyForwarderOptions : ForwarderOptions
+    {
+        public string DomainName { get; set; }
+    }
+
+    public class AnonAddyForwarder : BaseForwarder<AnonAddyForwarderOptions>
+    {
+        protected override string RequestUri => "https://app.anonaddy.com/api/v1/aliases";
+
+        protected override bool CanGenerate(AnonAddyForwarderOptions options)
+        {
+            return !string.IsNullOrWhiteSpace(options.ApiKey) && !string.IsNullOrWhiteSpace(options.DomainName);
+        }
+
+        protected override void ConfigureHeaders(HttpRequestHeaders headers, AnonAddyForwarderOptions options)
+        {
+            headers.Add("Authorization", $"Bearer {options.ApiKey}");
+        }
+
+        protected override Task<HttpContent> GetContentAsync(IApiService apiService, AnonAddyForwarderOptions options)
+        {
+            return Task.FromResult<HttpContent>(new FormUrlEncodedContent(new Dictionary<string, string>
+            {
+                ["domain"] = options.DomainName
+            }));
+        }
+
+        protected override string HandleResponse(JObject result)
+        {
+            return result["data"]?["email"]?.ToString();
+        }
+    }
+}
diff --git a/src/Core/Services/EmailForwarders/BaseForwarder.cs b/src/Core/Services/EmailForwarders/BaseForwarder.cs
new file mode 100644
index 000000000..b31393746
--- /dev/null
+++ b/src/Core/Services/EmailForwarders/BaseForwarder.cs
@@ -0,0 +1,63 @@
+using System;
+using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Threading.Tasks;
+using Bit.Core.Abstractions;
+using Bit.Core.Exceptions;
+using Newtonsoft.Json.Linq;
+
+namespace Bit.Core.Services.EmailForwarders
+{
+    public abstract class BaseForwarder<T>
+        where T : ForwarderOptions
+    {
+        protected abstract string RequestUri { get; }
+
+        public async Task<string> GenerateAsync(IApiService apiService, T options)
+        {
+            if (!CanGenerate(options))
+            {
+                return Constants.DefaultUsernameGenerated;
+            }
+
+            using (var requestMessage = new HttpRequestMessage())
+            {
+                requestMessage.Version = new Version(1, 0);
+                requestMessage.Method = HttpMethod.Post;
+                requestMessage.RequestUri = new Uri(RequestUri);
+                requestMessage.Headers.Add("Accept", "application/json");
+
+                ConfigureHeaders(requestMessage.Headers, options);
+                requestMessage.Content = await GetContentAsync(apiService, options);
+
+                try
+                {
+                    var response = await apiService.SendAsync(requestMessage);
+
+                    var responseJsonString = await response.Content.ReadAsStringAsync();
+
+                    return HandleResponse(JObject.Parse(responseJsonString));
+                }
+                catch (ApiException ex)
+                {
+                    if (IsRequestSecretInvalid(ex))
+                    {
+                        throw new ForwardedEmailInvalidSecretException(ex);
+                    }
+
+                    throw;
+                }
+            }
+        }
+
+        protected virtual bool CanGenerate(T options) => !string.IsNullOrWhiteSpace(options.ApiKey);
+
+        protected abstract void ConfigureHeaders(HttpRequestHeaders headers, T options);
+
+        protected abstract Task<HttpContent> GetContentAsync(IApiService apiService, T options);
+
+        protected abstract string HandleResponse(JObject result);
+
+        protected virtual bool IsRequestSecretInvalid(ApiException ex) => ex.Error?.StatusCode == System.Net.HttpStatusCode.Unauthorized;
+    }
+}
diff --git a/src/Core/Services/EmailForwarders/DuckDuckGoForwarder.cs b/src/Core/Services/EmailForwarders/DuckDuckGoForwarder.cs
new file mode 100644
index 000000000..7e9579be5
--- /dev/null
+++ b/src/Core/Services/EmailForwarders/DuckDuckGoForwarder.cs
@@ -0,0 +1,25 @@
+using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Threading.Tasks;
+using Bit.Core.Abstractions;
+using Newtonsoft.Json.Linq;
+
+namespace Bit.Core.Services.EmailForwarders
+{
+    public class DuckDuckGoForwarder : BaseForwarder<ForwarderOptions>
+    {
+        protected override string RequestUri => "https://quack.duckduckgo.com/api/email/addresses";
+
+        protected override void ConfigureHeaders(HttpRequestHeaders headers, ForwarderOptions options)
+        {
+            headers.Add("Authorization", $"Bearer {options.ApiKey}");
+        }
+
+        protected override Task<HttpContent> GetContentAsync(IApiService apiService, ForwarderOptions options) => Task.FromResult<HttpContent>(null);
+
+        protected override string HandleResponse(JObject result)
+        {
+            return $"{result["address"]?.ToString()}@duck.com";
+        }
+    }
+}
diff --git a/src/Core/Services/EmailForwarders/FastmailForwarder.cs b/src/Core/Services/EmailForwarders/FastmailForwarder.cs
new file mode 100644
index 000000000..a47229861
--- /dev/null
+++ b/src/Core/Services/EmailForwarders/FastmailForwarder.cs
@@ -0,0 +1,98 @@
+using System;
+using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Text;
+using System.Threading.Tasks;
+using Bit.Core.Abstractions;
+using Bit.Core.Exceptions;
+using Newtonsoft.Json.Linq;
+
+namespace Bit.Core.Services.EmailForwarders
+{
+    public class FastmailForwarder : BaseForwarder<ForwarderOptions>
+    {
+        protected override string RequestUri => "https://api.fastmail.com/jmap/api/";
+
+        protected override void ConfigureHeaders(HttpRequestHeaders headers, ForwarderOptions options)
+        {
+            headers.Add("Authorization", $"Bearer {options.ApiKey}");
+        }
+
+        protected override async Task<HttpContent> GetContentAsync(IApiService apiService, ForwarderOptions options)
+        {
+            string accountId = null;
+            try
+            {
+                accountId = await apiService.GetFastmailAccountIdAsync(options.ApiKey);
+            }
+            catch (ApiException ex)
+            {
+                if (IsRequestSecretInvalid(ex))
+                {
+                    throw new ForwardedEmailInvalidSecretException(ex);
+                }
+
+                throw;
+            }
+
+            var requestJObj = new JObject
+            {
+                new JProperty("using",
+                    new JArray { "https://www.fastmail.com/dev/maskedemail", "urn:ietf:params:jmap:core" }),
+                new JProperty("methodCalls",
+                    new JArray
+                    {
+                        new JArray
+                        {
+                            "MaskedEmail/set",
+                            new JObject
+                            {
+                                ["accountId"] = accountId,
+                                ["create"] = new JObject
+                                {
+                                    ["new-masked-email"] = new JObject
+                                    {
+                                        ["state"] = "enabled",
+                                        ["description"] = "",
+                                        ["url"] = "",
+                                        ["emailPrefix"] = ""
+                                    }
+                                }
+                            },
+                            "0"
+                        }
+                    })
+            };
+
+            return new StringContent(requestJObj.ToString(), Encoding.UTF8, "application/json");
+        }
+
+        protected override string HandleResponse(JObject result)
+        {
+            if (result["methodResponses"] == null || !result["methodResponses"].HasValues ||
+                !result["methodResponses"][0].HasValues)
+            {
+                throw new Exception("Fastmail error: could not parse response.");
+            }
+            if (result["methodResponses"][0][0].ToString() == "MaskedEmail/set")
+            {
+                if (result["methodResponses"][0][1]?["created"]?["new-masked-email"] != null)
+                {
+                    return result["methodResponses"][0][1]?["created"]?["new-masked-email"]?["email"].ToString();
+                }
+                if (result["methodResponses"][0][1]?["notCreated"]?["new-masked-email"] != null)
+                {
+                    throw new Exception("Fastmail error: " +
+                                        result["methodResponses"][0][1]?["created"]?["new-masked-email"]?["description"].ToString());
+                }
+            }
+            else if (result["methodResponses"][0][0].ToString() == "error")
+            {
+                throw new Exception("Fastmail error: " + result["methodResponses"][0][1]?["description"].ToString());
+            }
+            throw new Exception("Fastmail error: could not parse response.");
+        }
+
+        protected override bool IsRequestSecretInvalid(ApiException ex) => base.IsRequestSecretInvalid(ex) || ex.Error?.StatusCode == System.Net.HttpStatusCode.Forbidden;
+    }
+}
diff --git a/src/Core/Services/EmailForwarders/FirefoxRelayForwarder.cs b/src/Core/Services/EmailForwarders/FirefoxRelayForwarder.cs
new file mode 100644
index 000000000..0094808f6
--- /dev/null
+++ b/src/Core/Services/EmailForwarders/FirefoxRelayForwarder.cs
@@ -0,0 +1,36 @@
+using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Text;
+using System.Threading.Tasks;
+using Bit.Core.Abstractions;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+
+namespace Bit.Core.Services.EmailForwarders
+{
+    public class FirefoxRelayForwarder : BaseForwarder<ForwarderOptions>
+    {
+        protected override string RequestUri => "https://relay.firefox.com/api/v1/relayaddresses/";
+
+        protected override void ConfigureHeaders(HttpRequestHeaders headers, ForwarderOptions options)
+        {
+            headers.Add("Authorization", $"Token {options.ApiKey}");
+        }
+
+        protected override Task<HttpContent> GetContentAsync(IApiService apiService, ForwarderOptions options)
+        {
+            return Task.FromResult<HttpContent>(new StringContent(
+                JsonConvert.SerializeObject(
+                new
+                {
+                    enabled = true,
+                    description = "Generated by Bitwarden."
+                }), Encoding.UTF8, "application/json"));
+        }
+
+        protected override string HandleResponse(JObject result)
+        {
+            return result["full_address"]?.ToString();
+        }
+    }
+}
diff --git a/src/Core/Services/EmailForwarders/ForwarderOptions.cs b/src/Core/Services/EmailForwarders/ForwarderOptions.cs
new file mode 100644
index 000000000..b640ebb39
--- /dev/null
+++ b/src/Core/Services/EmailForwarders/ForwarderOptions.cs
@@ -0,0 +1,7 @@
+namespace Bit.Core.Services.EmailForwarders
+{
+    public class ForwarderOptions
+    {
+        public string ApiKey { get; set; }
+    }
+}
diff --git a/src/Core/Services/EmailForwarders/SimpleLoginForwarder.cs b/src/Core/Services/EmailForwarders/SimpleLoginForwarder.cs
new file mode 100644
index 000000000..384e4adf2
--- /dev/null
+++ b/src/Core/Services/EmailForwarders/SimpleLoginForwarder.cs
@@ -0,0 +1,25 @@
+using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Threading.Tasks;
+using Bit.Core.Abstractions;
+using Newtonsoft.Json.Linq;
+
+namespace Bit.Core.Services.EmailForwarders
+{
+    public class SimpleLoginForwarder : BaseForwarder<ForwarderOptions>
+    {
+        protected override string RequestUri => "https://app.simplelogin.io/api/alias/random/new";
+
+        protected override void ConfigureHeaders(HttpRequestHeaders headers, ForwarderOptions options)
+        {
+            headers.Add("Authentication", options.ApiKey);
+        }
+
+        protected override Task<HttpContent> GetContentAsync(IApiService apiService, ForwarderOptions options) => Task.FromResult<HttpContent>(null);
+
+        protected override string HandleResponse(JObject result)
+        {
+            return result["alias"]?.ToString();
+        }
+    }
+}
diff --git a/src/Core/Services/UsernameGenerationService.cs b/src/Core/Services/UsernameGenerationService.cs
index a2f70224a..9ec9fa215 100644
--- a/src/Core/Services/UsernameGenerationService.cs
+++ b/src/Core/Services/UsernameGenerationService.cs
@@ -1,7 +1,9 @@
-using System.Threading.Tasks;
+using System.Text;
+using System.Threading.Tasks;
 using Bit.Core.Abstractions;
 using Bit.Core.Enums;
 using Bit.Core.Models.Domain;
+using Bit.Core.Services.EmailForwarders;
 using Bit.Core.Utilities;
 
 namespace Bit.Core.Services
@@ -12,7 +14,7 @@ namespace Bit.Core.Services
         private readonly ICryptoService _cryptoService;
         private readonly IApiService _apiService;
         private readonly IStateService _stateService;
-        readonly LazyResolve<ILogger> _logger = new LazyResolve<ILogger>("logger");
+        readonly LazyResolve<ILogger> _logger = new LazyResolve<ILogger>();
         private UsernameGenerationOptions _optionsCache;
 
         public UsernameGenerationService(
@@ -104,7 +106,7 @@ namespace Bit.Core.Services
 
             if (options.PlusAddressedEmailType == UsernameEmailType.Random)
             {
-                var randomString = await RandomStringAsync(8);
+                var randomString = await _cryptoService.RandomStringAsync(8);
                 return options.PlusAddressedEmail.Insert(atIndex, $"+{randomString}");
             }
             else
@@ -124,7 +126,7 @@ namespace Bit.Core.Services
 
             if (options.CatchAllEmailType == UsernameEmailType.Random)
             {
-                var randomString = await RandomStringAsync(8);
+                var randomString = await _cryptoService.RandomStringAsync(8);
                 return string.Format(CATCH_ALL_EMAIL_DOMAIN_FORMAT, randomString, catchAllEmailDomain);
             }
 
@@ -133,85 +135,34 @@ namespace Bit.Core.Services
 
         private async Task<string> GenerateForwardedEmailAliasAsync(UsernameGenerationOptions options)
         {
+            if (options.ServiceType == ForwardedEmailServiceType.AnonAddy)
+            {
+                return await new AnonAddyForwarder()
+                                    .GenerateAsync(_apiService, (AnonAddyForwarderOptions)options.GetForwarderOptions());
+            }
+
+            BaseForwarder<ForwarderOptions> simpleForwarder = null;
+
             switch (options.ServiceType)
             {
-                case ForwardedEmailServiceType.AnonAddy:
-                    if (string.IsNullOrWhiteSpace(options.AnonAddyApiAccessToken) || string.IsNullOrWhiteSpace(options.AnonAddyDomainName))
-                    {
-                        return Constants.DefaultUsernameGenerated;
-                    }
-                    return await _apiService.GetUsernameFromAsync(ForwardedEmailServiceType.AnonAddy,
-                        new UsernameGeneratorConfig()
-                        {
-                            ApiToken = options.AnonAddyApiAccessToken,
-                            Domain = options.AnonAddyDomainName,
-                            Url = "https://app.anonaddy.com/api/v1/aliases"
-                        });
-
                 case ForwardedEmailServiceType.FirefoxRelay:
-                    if (string.IsNullOrWhiteSpace(options.FirefoxRelayApiAccessToken))
-                    {
-                        return Constants.DefaultUsernameGenerated;
-                    }
-                    return await _apiService.GetUsernameFromAsync(ForwardedEmailServiceType.FirefoxRelay,
-                        new UsernameGeneratorConfig()
-                        {
-                            ApiToken = options.FirefoxRelayApiAccessToken,
-                            Url = "https://relay.firefox.com/api/v1/relayaddresses/"
-                        });
-
+                    simpleForwarder = new FirefoxRelayForwarder();
+                    break;
                 case ForwardedEmailServiceType.SimpleLogin:
-                    if (string.IsNullOrWhiteSpace(options.SimpleLoginApiKey))
-                    {
-                        return Constants.DefaultUsernameGenerated;
-                    }
-                    return await _apiService.GetUsernameFromAsync(ForwardedEmailServiceType.SimpleLogin,
-                        new UsernameGeneratorConfig()
-                        {
-                            ApiToken = options.SimpleLoginApiKey,
-                            Url = "https://app.simplelogin.io/api/alias/random/new"
-                        });
+                    simpleForwarder = new SimpleLoginForwarder();
+                    break;
                 case ForwardedEmailServiceType.DuckDuckGo:
-                    if (string.IsNullOrWhiteSpace(options.DuckDuckGoApiKey))
-                    {
-                        return Constants.DefaultUsernameGenerated;
-                    }
-                    return await _apiService.GetUsernameFromAsync(ForwardedEmailServiceType.DuckDuckGo,
-                        new UsernameGeneratorConfig()
-                        {
-                            ApiToken = options.DuckDuckGoApiKey,
-                            Url = "https://quack.duckduckgo.com/api/email/addresses"
-                        });
+                    simpleForwarder = new DuckDuckGoForwarder();
+                    break;
                 case ForwardedEmailServiceType.Fastmail:
-                    if (string.IsNullOrWhiteSpace(options.FastMailApiKey))
-                    {
-                        return Constants.DefaultUsernameGenerated;
-                    }
-
-                    return await _apiService.GetUsernameFromAsync(ForwardedEmailServiceType.Fastmail,
-                        new UsernameGeneratorConfig()
-                        {
-                            ApiToken = options.FastMailApiKey,
-                            Url = "https://api.fastmail.com/jmap/api/"
-                        });
+                    simpleForwarder = new FastmailForwarder();
+                    break;
                 default:
                     _logger.Value.Error($"Error UsernameGenerationService: ForwardedEmailServiceType {options.ServiceType} not implemented.");
                     return Constants.DefaultUsernameGenerated;
             }
-        }
 
-        private async Task<string> RandomStringAsync(int length)
-        {
-            var str = "";
-            var charSet = "abcdefghijklmnopqrstuvwxyz1234567890";
-
-            for (var i = 0; i < length; i++)
-            {
-                var randomCharIndex = await _cryptoService.RandomNumberAsync(0, charSet.Length - 1);
-                str += charSet[randomCharIndex];
-            }
-
-            return str;
+            return await simpleForwarder.GenerateAsync(_apiService, options.GetForwarderOptions());
         }
 
         private string Capitalize(string str)