I actually thought HTTP/2 was enabled by default in Chrome, but back in early 2015 there was still a special flag (via a GUI) you had to set.
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How to enable HTTP/2 – SPDY4 in Chrome#
Note (2026): the steps below no longer apply. Chrome removed SPDY in May 2016 and HTTP/2 is enabled by default, so the Enable SPDY/4 flag described here doesn’t exist anymore. There’s nothing to toggle. The original instructions are kept below for the historical record.
Back in 2015, you’d go to the chrome://flags page (I can’t link to it directly, as the browser won’t allow direct links to the settings page) in your Chrome browser. Search for HTTP/2. Find the option called Enable SPDY/4.
Next, restart Chrome and SPDY4 will be enabled. This is one of the earlier drafts of HTTP/2 (at the time of writing, HTTP/2 draft 14) that will now be enabled. If you’re using Firefox 36 or higher, HTTP/2 support is fully baked in and enabled by default .
If you’re running Chromes nightly “canary” build, you can view the Protocol used in the Network Tab . Even though the SPDY-HTTP2 option is disabled by default, the before and after protocols are exactly the same: h2-14.
It may just be that Google has different settings for its own domains, that have hard-coded HTTP/2 support.
Before & after enabling HTTP/2#
Before:
After enabling SPDY, HTTP/2:
This’ll need a bit more testing to be sure.
More on HTTP/2?#
Interested in HTTP/2 news? Have a look at some of the following articles.
- Server Side Push with HTTP2 and nghttp2
- The final HTTP/2 spec announcement
- Architecting websites for the HTTP/2 era (everything you need to know as a developer to fully use HTTP/2)
- Does HTTP/2 or SPDY actually help speed up your site?