SPDY (pronounced speedy) is an open networking protocol developed primarily at Google for transporting web content. SPDY manipulates HTTP traffic, with particular goals of reducing web page load latency and improving web security.PDY is a versioned protocol. In its control frames there are 15 dedicated bits to indicate the version of the session protocol. 1  Version 1: version 1 of the SPDY protocol is not used anymore. 2  Version 2: soon to be discontinued.