With the Chrome browser already making plans to retire SPDY in favor of HTTP/2 I started testing sites to see how many of them advertised support for HTTP/2. No surprise that Google does:
$ openssl s_client -connect google.com:443 -nextprotoneg ”
CONNECTED(00000003)
Protocols advertised by server: h2-15, h2-14, spdy/3.1, spdy/3, http/1.1
The h2-15 and h2-14 refer to the HTTP/2 draft version ( 14 and 15 in this case, draft 17 was published last week ).
The response I got from Facebook turned up something interesting:
$ openssl s_client -connect facebook.com:443 -nextprotoneg ”
CONNECTED(00000003)
Protocols advertised by server: spdy/3.1-fb-0.5, spdy/3.1, spdy/3, http/1.1
I don’t recall seeing spdy/3.1-fb-0.5 before. It comes from the Facebook proxygen HTTP library.
Chrome doesn’t check for this version of SPDY, I’m assuming no other regular browsers do either. My guess is the only clients that support this are Facebook mobile apps.