diff --git a/src/HttpMock.Integration.Tests/MultipleTestsUsingTheSameStubServerWithDifferentHttpMethods.cs b/src/HttpMock.Integration.Tests/MultipleTestsUsingTheSameStubServerWithDifferentHttpMethods.cs
index 5848b6e..10f3e23 100644
--- a/src/HttpMock.Integration.Tests/MultipleTestsUsingTheSameStubServerWithDifferentHttpMethods.cs
+++ b/src/HttpMock.Integration.Tests/MultipleTestsUsingTheSameStubServerWithDifferentHttpMethods.cs
@@ -102,6 +102,19 @@ public void If_no_Mocked_Endpoints_matched_then_should_return_404_with_HttpMockE
 			}
 		}
 
+		[Test]
+		public void Should_return_dynamic_data()
+		{
+			string value = "test1";
+			_httpMockRepository
+				.Stub(x => x.Get("/endpoint"))
+				.Return(() => value)
+				.OK();
+			AssertResponse("GET", "test1");
+			value = "test2";
+			AssertResponse("GET", "test2");
+		}
+
 		private void AssertResponse(string method, string expected)
 		{
 			var webRequest = (HttpWebRequest) WebRequest.Create(_endpointToHit);
diff --git a/src/HttpMock/BufferedBody.cs b/src/HttpMock/BufferedBody.cs
index 621526d..0c1e2c4 100644
--- a/src/HttpMock/BufferedBody.cs
+++ b/src/HttpMock/BufferedBody.cs
@@ -7,29 +7,29 @@ namespace HttpMock
 {
 	class BufferedBody : IResponse
 	{
-		ArraySegment<byte> data;
+		readonly Func<byte[]> dataFunc;
 
 		public BufferedBody(string data) : this(data, Encoding.UTF8) { }
 		public BufferedBody(string data, Encoding encoding) : this(encoding.GetBytes(data)) { }
-		public BufferedBody(byte[] data) : this(new ArraySegment<byte>(data)) { }
-		public BufferedBody(ArraySegment<byte> data)
+		public BufferedBody(byte[] data) : this(() => data) { }
+		public BufferedBody(Func<string> data) : this(() => Encoding.UTF8.GetBytes(data())) { }
+		public BufferedBody(Func<byte[]> data)
 		{
-			this.data = data;
-		    Length = data.Count;
+			this.dataFunc = data;
 		}
 
-	    public int Length { get; private set; }
+		public Func<int> Length => () => dataFunc().Length;
 
-	    public IDisposable Connect(IDataConsumer channel)
+		public IDisposable Connect(IDataConsumer channel)
 		{
 			// null continuation, consumer must swallow the data immediately.
-			channel.OnData(data, null);
+			var bytes = new ArraySegment<byte>(dataFunc());
+			channel.OnData(bytes, null);
 			channel.OnEnd();
 			return null;
 		}
 
 		public void SetRequestHeaders(IDictionary<string, string> requestHeaders) {
-			
 		}
 	}
 
@@ -40,7 +40,6 @@ public IDisposable Connect(IDataConsumer channel) {
 		}
 
 		public void SetRequestHeaders(IDictionary<string, string> requestHeaders) {
-			
 		}
 	}
 }
\ No newline at end of file
diff --git a/src/HttpMock/IRequestStub.cs b/src/HttpMock/IRequestStub.cs
index 3f0f678..9fdd373 100644
--- a/src/HttpMock/IRequestStub.cs
+++ b/src/HttpMock/IRequestStub.cs
@@ -7,6 +7,7 @@ namespace HttpMock
 	public interface IRequestStub
 	{
 		IRequestStub Return(string responseBody);
+		IRequestStub Return(Func<string> responseBody);
 		IRequestStub ReturnFile(string pathToFile);
 		IRequestStub WithParams(IDictionary<string, string> nameValueCollection);
 		void OK();
diff --git a/src/HttpMock/RequestHandler.cs b/src/HttpMock/RequestHandler.cs
index a6b483d..3240f83 100644
--- a/src/HttpMock/RequestHandler.cs
+++ b/src/HttpMock/RequestHandler.cs
@@ -8,10 +8,10 @@
 
 namespace HttpMock
 {
-    public class RequestHandler : IRequestHandler, IRequestStub, IRequestVerify
-    {
+	public class RequestHandler : IRequestHandler, IRequestStub, IRequestVerify
+	{
 		private readonly ResponseBuilder _webResponseBuilder = new ResponseBuilder();
-	    private readonly IList<Func<string, bool>> _constraints = new List<Func<string, bool>>();
+		private readonly IList<Func<string, bool>> _constraints = new List<Func<string, bool>>();
 		private readonly Queue<ReceivedRequest> _observedRequests = new Queue<ReceivedRequest>();
 
 		public RequestHandler(string path, IRequestProcessor requestProcessor) {
@@ -34,16 +34,21 @@ public IRequestStub Return(string responseBody) {
 			return this;
 		}
 
+		public IRequestStub Return(Func<string> responseBody) {
+			_webResponseBuilder.Return(responseBody);
+			return this;
+		}
+
 		public IRequestStub ReturnFile(string pathToFile) {
 			_webResponseBuilder.WithFile(pathToFile);
-			
+
 			return this;
 		}
 
 		public IRequestStub ReturnFileRange(string pathToFile, int from, int to)
 		{
 			_webResponseBuilder.WithFileRange(pathToFile, from, to);
-			
+
 			return this;
 		}
 
@@ -80,10 +85,10 @@ public IRequestStub AddHeader(string header, string headerValue) {
 		}
 
 		public IRequestStub WithUrlConstraint(Func<string, bool> constraint)
-        {
-            _constraints.Add(constraint);
-            return this;
-        }
+		{
+			_constraints.Add(constraint);
+			return this;
+		}
 
 		public override string ToString() {
 			var sb = new StringBuilder();
@@ -107,10 +112,10 @@ public string GetBody() {
 			return _observedRequests.Peek().Body;
 		}
 
-	    public bool CanVerifyConstraintsFor(string url)
-	    {
-	        return _constraints.All(c => c(url));
-	    }
+		public bool CanVerifyConstraintsFor(string url)
+		{
+			return _constraints.All(c => c(url));
+		}
 
 		public ReceivedRequest LastRequest()
 		{
diff --git a/src/HttpMock/ResponseBuilder.cs b/src/HttpMock/ResponseBuilder.cs
index fd45569..0ad9f9f 100644
--- a/src/HttpMock/ResponseBuilder.cs
+++ b/src/HttpMock/ResponseBuilder.cs
@@ -13,14 +13,22 @@ public class ResponseBuilder
 		private  HttpStatusCode _httpStatusCode = HttpStatusCode.OK;
 		private string _contentType = "text/plain";
 		private IResponse _response = new BufferedBody("");
-		private int _contentLength = 0;
+		private Func<int> _contentLength = () => 0;
 		private Dictionary<string, string> _headers = new Dictionary<string, string>();
 
 		public ResponseBuilder Return(string body) {
-		    var bufferedBody = new BufferedBody(body);
-		    _contentLength = bufferedBody.Length;
-		    _response = bufferedBody;
-			
+			var bufferedBody = new BufferedBody(body);
+			_contentLength = bufferedBody.Length;
+			_response = bufferedBody;
+
+			return this;
+		}
+
+		public ResponseBuilder Return(Func<string> body) {
+			var bufferedBody = new BufferedBody(body);
+			_contentLength = bufferedBody.Length;
+			_response = bufferedBody;
+
 			return this;
 		}
 
@@ -30,8 +38,8 @@ public IDataProducer BuildBody(IDictionary<string, string> headers) {
 		}
 
 		public HttpResponseHead BuildHeaders() {
-			AddHeader(HttpHeaderNames.ContentType, _contentType); 
-			AddHeader(HttpHeaderNames.ContentLength, _contentLength.ToString());
+			AddHeader(HttpHeaderNames.ContentType, _contentType);
+			AddHeader(HttpHeaderNames.ContentLength, _contentLength().ToString());
 
 			var headers = new HttpResponseHead
 			{
@@ -39,8 +47,6 @@ public HttpResponseHead BuildHeaders() {
 				Headers = _headers
 			};
 			return headers;
-
-			
 		}
 
 		public void WithStatus(HttpStatusCode httpStatusCode) {
@@ -54,7 +60,7 @@ public void WithContentType(string contentType) {
 		public void WithFile(string pathToFile) {
 			if(File.Exists(pathToFile)) {
 				var fileInfo = new FileInfo(pathToFile);
-				_contentLength = (int)fileInfo.Length;
+				_contentLength = () => (int)fileInfo.Length;
 				_response = new FileResponseBody(pathToFile);
 			} else {
 				throw new InvalidOperationException("File does not exist/accessible at :" + pathToFile);
@@ -66,7 +72,7 @@ public void WithFileRange(string pathToFile, int from, int to)
 			if (File.Exists(pathToFile))
 			{
 				var fileInfo = new FileInfo(pathToFile);
-				_contentLength = (to - from) +1;
+				_contentLength = () => (to - from) + 1;
 				_response = new FileResponseBody(pathToFile);
 				AddHeader(HttpResponseHeader.ContentRange.ToString(), string.Format("bytes={0}-{1}/{2}",  from, to, fileInfo.Length));
 			}