Script that initiates different browsers?

Question

PHP

Hello.
There is a service that can display the site on different devices.
As a matter of fact, here it is http://responsivetest.net/#u=http://www.zootemplat...
And how to make the script imitate different browsers and mail services.
This is necessary so that when laying out an email template, you can view it in different browsers.
As a person who understands this, I understand that it is better to view it through a real browser and mail service. But the implementation of this script is not necessary.
The question is not only whether there are ready-made scripts that you can install on your server and use. And if there is no such script, then how can you simulate different mail services?
What should be taken into account, what kind of work logic should be?

Answer 1

imitated different browsers - https://www.browserstack.com/
imitated mail services - what is the difference between mail services? O_O After all, you open these services through a browser, you can do the same yourself - open a letter in a browser, the only difference will be in the width / height, which is limited for mailers, everything else is plain / html text

Answer 2

So do you have to imitate or initiate?
It is still possible to initiate, although it is unlikely that this will work normally.
But imitating is not realistic. More precisely, it is real, but the costs of implementation and support are beyond.

Answer 3

There is something similar in the built-in Chrome developer tools (it should also be in FF). To tell the web server which version of the site to serve, you can use User-agent switchers (browser extensions)