This generates the password on a server you don't control.
I recommend not using it.
Using 'tr -dc A-Za-z0-9 < /dev/urandom | head -c $length' is more secure and available on your linux or osx machine even more easily than waiting a second for a server to run some java off in a magic black box.
You can also try indexing into /usr/share/dict/words for a correcthorsebatterystaple-style password. I'm sure there's a cute on-liner, I did it in Python because that took a lot less time than all the man page searching how to do it with Unix text processing tools would have taken.
Yes, it would be better to remember random characters of the same length. But most people don't. I personally have one password I use to sign into 1password and a small other set of critical services, and longer random passwords for everything else. I personally don't worry about nation state adversaries so I can make myself less vulnerable to mass automated attacks and targeted attacks by non-experts. It's important to remember not to let perfect be the enemy of the good, and important not to discount the cost of DOSing yourself. I reduced my security after I lost access to something of value.
Here's a perl one for fun :)
perl -MList::Util=shuffle -0ane 'print ((shuffle @F)[0..3],"\n")' < /usr/share/dict/words
Why thank you :)
From the perspective of someone who's just getting started with learning to code, perl seems like a pile of spermaceti: was once very important, could be turned into beautifully smelling products so long as you didn't pay too much attention to the production process, and no longer needed because of modern synthetics :)
But I've only ever read people mocking perl, never built anything with it. It appears immensely powerful, but collapsing arrays by default makes no sense at all.
I think most of the people who were into Perl for the "beauty" ended up going to ruby.
People who were into it for CPAN went to python.
You might find this interesting, as you can see the spirit is alive and well: https://github.com/learnbyexample/Command-line-text-processi...
ruby -0ane 'print $F.shuffle[0..3].join,"\n"' < /usr/share/dict/words
If you're intrigued by the idea of perl one-liners, go explore ruby.