diff --git a/src/formulate.app/Forms/Handlers/Email/EmailConfiguration.cs b/src/formulate.app/Forms/Handlers/Email/EmailConfiguration.cs
index 427618d1..7b6ee491 100644
--- a/src/formulate.app/Forms/Handlers/Email/EmailConfiguration.cs
+++ b/src/formulate.app/Forms/Handlers/Email/EmailConfiguration.cs
@@ -1,7 +1,12 @@
 namespace formulate.app.Forms.Handlers.Email
 {
+
+    // Namespaces.
+    using formulate.core.Extensions;
+    using Newtonsoft.Json;
     using System;
     using System.Collections.Generic;
+    using System.Linq;
 
     /// <summary>
     /// Configuration used by <see cref="EmailHandler"/>.
@@ -16,12 +21,32 @@ public class EmailConfiguration : IEmailSenderRecipientConfiguration
         /// <summary>
         /// Gets or sets the recipients of the email.
         /// </summary>
-        public IEnumerable<Recipient> Recipients { get; set; }
+        [JsonProperty("recipients")]
+        public IEnumerable<Recipient> RecipientsData { get; set; }
+
+        /// <summary>
+        /// Gets the recipients of the email.
+        /// </summary>
+        /// <remarks>
+        /// This is a duplicate property because this version implements the interface,
+        /// which requires a slightly different data type.
+        /// </remarks>
+        public IEnumerable<string> Recipients => RecipientsData.MakeSafe().Select(x => x.Email).ToArray();
 
         /// <summary>
         /// Gets or sets the fields containing the recipients of the email.
         /// </summary>
-        public IEnumerable<Guid> RecipientFields { get; set; }
+        [JsonProperty("recipientFields")]
+        public IEnumerable<GuidId> RecipientFieldsData { get; set; }
+
+        /// <summary>
+        /// Gets the fields containing the recipients of the email.
+        /// </summary>
+        /// <remarks>
+        /// This is a duplicate property because this version implements the interface,
+        /// which requires a slightly different data type.
+        /// </remarks>
+        public IEnumerable<Guid> RecipientFields => RecipientFieldsData.MakeSafe().Select(x => x.Id).ToArray();
 
         /// <summary>
         /// Gets or sets the type of delivery for the recipients (e.g., to, cc, bcc).
@@ -31,7 +56,17 @@ public class EmailConfiguration : IEmailSenderRecipientConfiguration
         /// <summary>
         /// Gets or sets the fields to include.
         /// </summary>
-        public IEnumerable<Guid> FieldsToInclude { get; set; }
+        [JsonProperty("fieldsToInclude")]
+        public IEnumerable<GuidId> FieldsToIncludeData { get; set; }
+
+        /// <summary>
+        /// Gets the fields to include.
+        /// </summary>
+        /// <remarks>
+        /// This is a convenience property that extracts the important data
+        /// from the other version of this property.
+        /// </remarks>
+        public IEnumerable<Guid> FieldsToInclude => FieldsToIncludeData.MakeSafe().Select(x => x.Id).ToArray();
 
         /// <summary>
         /// Gets or sets the message.
diff --git a/src/formulate.app/Forms/Handlers/Email/EmailHandler.cs b/src/formulate.app/Forms/Handlers/Email/EmailHandler.cs
index f2dc7288..e7bf4f0c 100644
--- a/src/formulate.app/Forms/Handlers/Email/EmailHandler.cs
+++ b/src/formulate.app/Forms/Handlers/Email/EmailHandler.cs
@@ -294,7 +294,6 @@ protected MailMessage PrepareEmailMessage(
 
             // Any allowed recipients (if not, abort early)?
             var rawRecipients = config.Recipients
-                .Select(x => x.Email)
                 .Concat(fieldEmails)
                 .Concat(extraEmails);
             var allowedRecipients = FilterEmails(rawRecipients);
diff --git a/src/formulate.app/Forms/Handlers/Email/IEmailSenderRecipientConfiguration.cs b/src/formulate.app/Forms/Handlers/Email/IEmailSenderRecipientConfiguration.cs
index d6e628e1..b47bde8d 100644
--- a/src/formulate.app/Forms/Handlers/Email/IEmailSenderRecipientConfiguration.cs
+++ b/src/formulate.app/Forms/Handlers/Email/IEmailSenderRecipientConfiguration.cs
@@ -21,7 +21,7 @@ public interface IEmailSenderRecipientConfiguration
         /// <summary>
         /// Gets the recipients of the email.
         /// </summary>
-        IEnumerable<Recipient> Recipients { get; }
+        IEnumerable<string> Recipients { get; }
 
         /// <summary>
         /// Gets the fields containing the recipients of the email.
diff --git a/src/formulate.app/Forms/Handlers/Email/RecipientField.cs b/src/formulate.app/Forms/Handlers/Email/RecipientField.cs
new file mode 100644
index 00000000..4daa6aae
--- /dev/null
+++ b/src/formulate.app/Forms/Handlers/Email/RecipientField.cs
@@ -0,0 +1,24 @@
+namespace formulate.app.Forms.Handlers.Email
+{
+
+    // Namespaces.
+    using System;
+
+    /// <summary>
+    /// An object that contains an ID that is a GUID.
+    /// </summary>
+    public class GuidId
+    {
+
+        #region Properties
+
+        /// <summary>
+        /// The GUID ID.
+        /// </summary>
+        public Guid Id { get; set; }
+
+        #endregion
+
+    }
+
+}
\ No newline at end of file
diff --git a/src/formulate.app/formulate.app.csproj b/src/formulate.app/formulate.app.csproj
index ff9f1572..27d10d08 100644
--- a/src/formulate.app/formulate.app.csproj
+++ b/src/formulate.app/formulate.app.csproj
@@ -350,6 +350,7 @@
     <Compile Include="Forms\Handlers\Email\EmailConfiguration.cs" />
     <Compile Include="Forms\Handlers\Email\EmailHandler.cs" />
     <Compile Include="Forms\Handlers\Email\IEmailSenderRecipientConfiguration.cs" />
+    <Compile Include="Forms\Handlers\Email\RecipientField.cs" />
     <Compile Include="Forms\Handlers\Email\Recipient.cs" />
     <Compile Include="Forms\Handlers\SendData\FieldMapping.cs" />
     <Compile Include="Forms\Handlers\SendData\IHandleSendDataResult.cs" />