I never ran into that problem with https://temp-mail.org. They cycle domains constantly.
You didn't run into that problem with temp-mail.org because you happen to use them on websites that don't bother blocking disposable email addresses -- or -- they do try to block them but use simplistic domain name checks.
But cycling domain names isn't enough to fool the more sophisticated disposable/throwaway email address detectors (especially the paid services) because they use extra heuristics of checking DNS MX records ip addresses.
E.g. temp-mail.org assigned the following random addresses "[email protected]" and "[email protected]". Both of those domains are easily detected as throwaway emails because they both share the same MX ip 24.199.65.21 :
- https://verifymail.io/domain/mcatag.com
- https://verifymail.io/domain/javnoi.com
On the other hand, the "@mcatag.com", "@javnoi.com", etc used by temp-mail.org is good enough to get past the websites that copy&paste the code from these StackOverflow answers that just use simplistic string matching : https://stackoverflow.com/questions/10976706/how-to-block-di...
It all depends on how much effort and cost the websites want to put into blocking disposable email addresses.
Even if you go through all that extra trouble to maintain a list of banned domains, the user can still just whip out a Hide-My-Email address ending in @icloud.com.
For those who own their own domain for emails, there are multiple ways of doing it - aliases, temporary IDs, filters, etc. Or use such services' backbone/infrastructure that can route the emails but you own the domain.