Google today announced it will drop support for SPDY on May 15, 2016 (the company’s previous timeline was “early 2016“). SPDY, which is not an acronym but just a short version of the word “speedy,” is a protocol — developed primarily at Google — to improve browsing by forcing SSL encryption for all sites and speeding up page loads.
Google chose May 15 because it is the anniversary of when HTTP/2, the second major version of Hypertext Transfer Protocol (HTTP), had its RFC document published. The company refers to HTTP/2 as “the next-generation protocol for transferring information on the web, improving upon HTTP/1.1 with more features leading to better performance.”
Google says it has seen huge adoption of HTTP/2 from both web servers and browsers over the past year, “with most now supporting HTTP/2.” In fact, the company shared that over 25 percent of resources in Chrome are currently served over HTTP/2, compared to less than 5 percent over SPDY.
So what will happen to servers that support SPDY but not HTTP/2? They will simply serve Chrome requests over HTTP/1.1.
Also on May 15, Chrome will drop support for the TLS extension NPN, which allows servers to negotiate SPDY and HTTP/2 connections with clients, in favor of ALPN, published by the IETF in 2014. Google says ALPN is already used 99 percent of the time to negotiate HTTP/2 with Chrome, and urges administrators of the remaining servers to add ALPN support by upgrading their SSL library.
HTTP is an application protocol that forms the foundation of data communication for the World Wide Web. Over the years, it has become dated, and there have been many initiatives to speed it up. HTTP/2 will be the first new version of the HTTP protocol since HTTP 1.1, which was standardized back in June 1999.
Google’s move to ditch SPDY should surprise no one, given that HTTP/2, currently being developed by the Hypertext Transfer Protocol Bis (httpbis) working group of the Internet Engineering Task Force (IETF), is based on SPDY. Key features such as multiplexing, header compression, prioritization, and protocol negotiation evolved from work done in SPDY.
The majority of the Web still uses HTTP 1.1, but browsers, of course, need to support new protocols before websites can use them. Other major browsers, including those from Microsoft, Mozilla, and Apple, will also move away from SPDY implementations and toward HTTP/2.