Shorten bitly with account free or payment account use only key of account API
have code for shorten link in bitly, yourself can generate 1- 100 -1.000k - 2.000k - redirect of your URL or link in seconds is very easy to use and work with Node .js
you only paste link need shorten and this generate lot link redirect in bitly for used in you spam letter , also can generate subdomains with same link bitly.
Conctact - https://t.me/r4gn4r0kr4