What exactly does the Google PageSpeed ​​Module do?

Question

Google

What does the https://developers.google.com/speed/pagespeed/module/ module do ?
Compresses CSS and JS? Does it compress pictures? Compresses the page code? Is something cached?

Answer 1

This infection is like an extra layer of cache on a website.
It takes your code, and, as far as possible, before issuing it to the client, creates a temporary copy in which it compresses css, html as much as possible, does various miracles with pictures, throws code blocks, removes quotes ... in fact, it looks like a js-minifier - it minimizes the code and image size to make the site open faster.
but this technology is very funny - one heals the other cripples. to adjust for yourself, prepare a little less than a week to twist this way and that. my config will not suit you, I have it junk in one, you may have it in another.
there are jokes like the picture does not load at all. why - because you have a redirect rule from English to root in htaccess - and it replaces /en with / everywhere, and in the word pagespeed-encoundted - there is en.
Then there is the topic that some browsers can't stand all sorts of modern image formats - it doesn't work again. The same goes for mobile phones. And although they say that there is some kind of future - the director will once put a pendal in your ass for not seeing a picture from an iPhone and you will quickly realize that everything that does not work must be quickly turned off, because it does not sway - can you finish it or no - he just needs a reason to kick you.
So the thing is contradictory. It doesn't even look like a solution out of the box. Although he claims

Answer 2

Crimp - twisted pair)))
As for me - you need to manually optimize everything yourself. In this matter, the quality will depend on this. And this one also "compresses" ...
But I don't know what exactly and how well it optimizes, and I would like to know.
By the way, another question is how to get it on a shared hosting? No way? To ask the hoster "well, put it, otherwise I'm too lazy to follow the recommendations, but it's the way it is, nuuuu ..."?))))))

Answer 3

He can do a lot of things. I use it to automatically render css above-the-fold in the header. Also, for example, he knows how to collect all the js on the page and load it after the dom has loaded (which is not always good, of course)