Great to see some fantastic #webperf work happening on GOV.UK at the moment. The team have been gradually removing the shard domain for critical assets, and it's made quite a difference! Images from Chrome on a 3G connection and S4 on 3G. 1/4
Considering where we were at the start of Feb: HTTP/1.1, SRI, shard domain, ~13 TCP connections. Now down to just 1 TCP connection in many cases. 2/4
And we can finally make the most the features H2 has to offer. Serving all assets off a single domain allows:
• all assets to use a connection that is up to speed (TCP slow start)
• prioritisation can happen across all assets
• no more h2 connection coalescing required
3/4