diff --git a/Release/include/cpprest/details/http_constants.dat b/Release/include/cpprest/details/http_constants.dat
index c867b4d07a..f2bd531be5 100644
--- a/Release/include/cpprest/details/http_constants.dat
+++ b/Release/include/cpprest/details/http_constants.dat
@@ -47,6 +47,7 @@ DAT(RequestUriTooLarge,    414, _XPLATSTR("Request Uri Too Large"))
 DAT(UnsupportedMediaType,  415, _XPLATSTR("Unsupported Media Type"))
 DAT(RangeNotSatisfiable,   416, _XPLATSTR("Requested range not satisfiable"))
 DAT(ExpectationFailed,     417, _XPLATSTR("Expectation Failed"))
+DAT(TooManyRequests,       429, _XPLATSTR("Too Many Requests"))
 DAT(InternalError,         500, _XPLATSTR("Internal Error"))
 DAT(NotImplemented,        501, _XPLATSTR("Not Implemented"))
 DAT(BadGateway,            502, _XPLATSTR("Bad Gateway"))