So we all know that not all browsers behave exactly the same, and then, we also have devices to worry about.
For the “responsiveness” I used to to use one of the many, many, many previewers out there…
ie. http://quirktools.com/screenfly and https://www.responsinator.com/ , they don’t work for me anymore, I don’t know why but all I see is a white page.
So I’ve used browsethemall but at times its not accurate.
However there’s this one tool to preview mobiles that always seems to be on the spot. appetize.io whoever isn’t as versatile Browesethemall.
By the way, I used to use tools like Browser Stack, but nowadays there aren’t enough differences with the view. I just test in Chrome. Near the end of the project I load Firefox and Safari, and a couple of mobile phones with whatever they have installed. Nothing else, nothing old. That’s because I work alone, if you have a team, you are part of a big company or you make open source stuff, you should make the right tests.
Using frameworks helps a lot to reduce those differences (if you know how to use them).