diff --git a/src/SendGrid/ISendGridClient.cs b/src/SendGrid/ISendGridClient.cs
new file mode 100644
index 000000000..8dfdfd318
--- /dev/null
+++ b/src/SendGrid/ISendGridClient.cs
@@ -0,0 +1,75 @@
+// <copyright file="SendGridClient.cs" company="SendGrid">
+// Copyright (c) SendGrid. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+// </copyright>
+
+using System;
+
+namespace SendGrid
+{
+	using System.Collections.Generic;
+	using System.Net.Http;
+	using System.Net.Http.Headers;
+	using System.Threading;
+	using System.Threading.Tasks;
+	using Helpers.Mail;
+
+	/// <summary>
+	/// A HTTP client wrapper for interacting with SendGrid's API
+	/// </summary>
+	public interface ISendGridClient
+	{
+		/// <summary>
+		/// Gets or sets the path to the API resource.
+		/// </summary>
+		string UrlPath { get; set; }
+
+		/// <summary>
+		/// Gets or sets the API version.
+		/// </summary>
+		string Version { get; set; }
+
+		/// <summary>
+		/// Gets or sets the request media type.
+		/// </summary>
+		string MediaType { get; set; }
+
+		/// <summary>
+		/// Add the authorization header, override to customize
+		/// </summary>
+		/// <param name="header">Authorization header</param>
+		/// <returns>Authorization value to add to the header</returns>
+		AuthenticationHeaderValue AddAuthorization( KeyValuePair<string, string> header );
+
+		/// <summary>
+		/// Make the call to the API server, override for testing or customization
+		/// </summary>
+		/// <param name="request">The parameters for the API call</param>
+		/// <param name="cancellationToken">Cancel the asynchronous call</param>
+		/// <returns>Response object</returns>
+		Task<Response> MakeRequest( HttpRequestMessage request, CancellationToken cancellationToken = default( CancellationToken ) );
+
+		/// <summary>
+		/// Prepare for async call to the API server
+		/// </summary>
+		/// <param name="method">HTTP verb</param>
+		/// <param name="requestBody">JSON formatted string</param>
+		/// <param name="queryParams">JSON formatted query paramaters</param>
+		/// <param name="urlPath">The path to the API endpoint.</param>
+		/// <param name="cancellationToken">Cancel the asynchronous call.</param>
+		/// <returns>Response object</returns>
+		/// <exception cref="Exception">The method will NOT catch and swallow exceptions generated by sending a request
+		/// through the internal http client. Any underlying exception will pass right through.
+		/// In particular, this means that you may expect
+		/// a TimeoutException if you are not connected to the internet.</exception>
+		Task<Response> RequestAsync( SendGridClient.Method method, string requestBody = null, string queryParams = null, string urlPath = null, CancellationToken cancellationToken = default( CancellationToken ) );
+
+		/// <summary>
+		/// Make a request to send an email through SendGrid asychronously.
+		/// </summary>
+		/// <param name="msg">A SendGridMessage object with the details for the request.</param>
+		/// <param name="cancellationToken">Cancel the asychronous call.</param>
+		/// <returns>A Response object.</returns>
+		Task<Response> SendEmailAsync( SendGridMessage msg, CancellationToken cancellationToken = default( CancellationToken ) );
+	}
+}
\ No newline at end of file
diff --git a/src/SendGrid/SendGridClient.cs b/src/SendGrid/SendGridClient.cs
index cd75b8278..114dc6dec 100644
--- a/src/SendGrid/SendGridClient.cs
+++ b/src/SendGrid/SendGridClient.cs
@@ -20,8 +20,8 @@ namespace SendGrid
     /// <summary>
     /// A HTTP client wrapper for interacting with SendGrid's API
     /// </summary>
-    public class SendGridClient
-    {
+    public class SendGridClient : ISendGridClient
+	{
         /// <summary>
         /// Gets or sets the path to the API resource.
         /// </summary>