I checked their website page (
https://jambler.io/mix-coins.php), but it looks like there are only 7 mixers which use their
script service where i've only heard 2 of them.
There are many free scripts out there you can use to create your mixing website but I can guarantee you will be the only one visiting that website.
Not only that, free script for something complex (whether it's mixer, exchange or something else) usually lead to disaster either due to bug or backdoor.