[mluggy]

How is this different/more scalable than running google tag manager as async, with the rest of the scripts as defer/async as well.

Not so long ago I side-project fassttt.com and thought the biggest issues are server-side, with bad images and improper caching. Ended up creating a complete minifier/compressor/cdn-enabler.

I since realized the problems are mostly client-side. Cumbersome styling framework and JS rendering engines that are dynamic and VERY hard to optimize.

BTW, if people only care about site-speed score, see https://nitropack.io/ which almost always give you a 100 score.

[yoavm]

Unfortunately, when it comes to analytics and conversion pixels, deferring everything isn't really a serious option because it literally means missing data. Essentially all your metrics would be skewed and your remarketing audiences would be missing potential users. But also from performance it isn't great - I came across this website yesterday that did more or less this, and the problem was that because everything was loaded just after the page was ready, things would get super slow the first few seconds you're trying to interact with it.

[mluggy]

If someone hasn't stayed long enough to trigger GA, is it really a user? :)

Another option: only delay the scripts the first time user has landed on your page

I think the single script embed is a good path (much better than asking people to change DNS, remove scripts or such). Maybe you can optimize other areas using JS (like images).

[yoavm]

Philosophically it's a great question :) I'm not a marketer, but I'm pretty sure that if you'd ask one what they think about losing the ability to do remarketing for all the users who bounced within the first 10 seconds of their visit, they would tell you it's perhaps their most important audience.

We'd definitely be looking to optimizing other areas too, though honestly our approach was more to get rid of as much as client-side JS as possible. There are so many other tools that will help your do your first-party optimizations: images, caching, bundling, but we couldn't find anything that takes care of optimizing your third-party stack while keeping it 100% functional.

[KaoruAoiShiho]

Yeah I am confused about this too, 10 seconds sounds like a big exaggeration. Your site should load in 1-2 seconds and the marketing can come the third second. However the page should already be interactive after the first 2 seconds. Doesn't quite need another service.

[yoavm]

I know it's hard to believe, but thankfully there are tools to measure this. Try https://web.dev/measure/ and see for yourself - many popular websites reach interactivity after 10 seconds.

Here are a few examples I recently tried:

https://lighthouse-dot-webdotdevsite.appspot.com//lh/html?ur...

https://lighthouse-dot-webdotdevsite.appspot.com//lh/html?ur...

https://lighthouse-dot-webdotdevsite.appspot.com//lh/html?ur...

[thettiguy]

They run those tests with like 1Mb/s connection though.

[yoavm]

Good point - by default Google Lighthouse is aiming at the 85th percentile of mobile connection speed, meaning you can ignore these metrics because you have a faster connection or device, but they are still true for ~15% of your mobile traffic. That's the reality of simply delaying scripts - you'll want to delay them more to achieve faster loading time, but the more you delay them the more data you lose.