Using Signed Exchanges to improve LCP Core Web Vital Page Experience metrics

eva2000

Well-known member
A good alternative to AMP for improving LCP (via improving TTFB) Core Web Vital metrics is Signed Exchanges. Cloudflare released its Automatic Signed Exchanges beta a while back during Speed Week 2021. I wrote up a guide including page speed tests for SXGs on my blog at https://blog.centminmod.com/2021/10...tomatic-signed-exchanges-google-search-cache/ :cool: :love:

Wordpress site Google search prefetched SXG cached page

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Xenforo forum Google search prefetched SXG cached page

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mazzly

Well-known member
Note to anyone using AMPXF and having the "AMP Real URL" option enabled in the Cloudflare dashboard: It is apparently not compatible with the SXG option as per their help section:
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Otherwise this looks quite interesting when it will get further support by browsers :) Especially for desktop

To improve the FCP/LCP speeds on our own forums we're currently running a home-made addon that inlines the critical css, and at the end loads other things that might be needed, but it is quite primitive, and having something like this preloading assets would be much nicer. :)
 

Mr. Jinx

Well-known member
Very interesting!
So if you would purchase just APO with the free plan, which is meant for Wordpress, you can also enable SXG and use it for other things like Xenforo sites?
 

eva2000

Well-known member
Note to anyone using AMPXF and having the "AMP Real URL" option enabled in the Cloudflare dashboard: It is apparently not compatible with the SXG option as per their help section:
Yes, Cloudflare SXG actually do one important feature that AMP Real URL does, Signed Exchanges itself allowing Google search to prefetch and preload the SXG cached copy ahead of time, that is where the speed benefits are i.e. look at LCP for new and returning visitors much faster with SXG cache

These metrics are for my Xenforo forum :)

New Visitors – TTFB
  • Google Android Search SXG cached referrals: 623.63 ms (22% faster)
  • Google Android Search non-SXG referrals: 799.99 ms
New Visitors – LCP
  • Google Android Search SXG cached referrals: 1,193.81 ms (19.3% faster)
  • Google Android Search non-SXG referrals: 1,479.58 ms
Returning Visitors – TTFB
  • Google Android Search SXG cached referrals: 237.09 ms (76.85% faster)
  • Google Android Search non-SXG referrals: 1,024.23 ms
Returning Visitors – LCP
  • Google Android Search SXG cached referrals: 771.79 ms (55.98% faster)
  • Google Android Search non-SXG referrals: 1,753.44 ms

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Forum origin CRuX for past rolling 28 days

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Otherwise this looks quite interesting when it will get further support by browsers :) Especially for desktop

Yes waiting on that, my mobile traffic is only 5-10% while my desktop is 90-95% of total!

To improve the FCP/LCP speeds on our own forums we're currently running a home-made addon that inlines the critical css, and at the end loads other things that might be needed, but it is quite primitive, and having something like this preloading assets would be much nicer
Nice :)

So if you would purchase just APO with the free plan, which is meant for Wordpress, you can also enable SXG and use it for other things like Xenforo sites?

Yes they should work together in theory but there can be gotchas with Cloudflare Wordpress APO if on same domain as non-Wordpress web apps. But SXG itself should work.
 

Kirby

Well-known member
Signed exchanges are an interesting technology, though I can understand why Mozilla Foundation does have concerns.

IMHO it would require two things for SXG to really see broad adoption:
  1. Support at least in Firefox as well
  2. Availibilty of cheap/free certificates
    Right now it seems like Digicert is the only CA that does offer certificates with the required X.509 extension - and only for expensive OV/EV certificates
That being said, I think our scores aren't too bad - even without AMP and SXG :)
 

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eva2000

Well-known member
Yeah wider adoption/requirement parameters would be nice - it's only Android mobile right now. Love to see desktop support as 95% of my visitors are desktop still !
 

JoyFreak

Well-known member
Otherwise this looks quite interesting when it will get further support by browsers :) Especially for desktop
Yeah, I'd wait for more support down the line.

To improve the FCP/LCP speeds on our own forums we're currently running a home-made addon that inlines the critical css, and at the end loads other things that might be needed, but it is quite primitive, and having something like this preloading assets would be much nicer. :)
Oh? Is this an add-on your currently developing? What's the ETA?
 
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