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

[eva2000]

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/

Wordpress site Google search prefetched SXG cached page






Xenforo forum Google search prefetched SXG cached page

 

[eva2000]

I've updated my Cloudflare Automated Signed Exchange article with my Google Analytics tracked Core Web Vital metrics comparing Google Android search referral traffic from SXG cached vs non-SXG cached sources https://blog.centminmod.com/2021/10...atic-signed-exchanges-google-search-cache/#ga

 

[mazzly]

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]

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]

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

Forum origin CRuX for past rolling 28 days

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]

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

 

[eva2000]

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]

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?

 

[mazzly]

Oh? Is this an add-on your currently developing? What's the ETA?

Currently in testing, but not sure if this can ever be released as it currently requires a bit of fiddling to work well Maybe at some later point

 

[rdn]

With XF2, I can't make it work.. maybe because of this header?

cache-control private, no-cache, max-age=0

 

[eva2000]

With XF2, I can't make it work.. maybe because of this header?

Yup https://community.centminmod.com/threads/cloudflare-automatic-signed-exchanges.22063/#post-93201