How are people getting founder's direct emails so quickly after a PH launch?

Hey r/SaaS,

I’ve noticed a weird pattern lately.

Every time a friend of mine launches a SaaS on Product Hunt or Indie Hackers, they get hit with 10-15 hyper-relevant cold emails within 2 hours.

Is there a specific SaaS growth hack or some API people are using to scrape this? I did some digging and found a few sites like FounderDB that claim to aggregate this data in real-time, but I’m curious if that’s the standard way people are doing it now.

It seems way more effective than just spray-and-pray on LinkedIn, but I don't want to burn my domain if these lists are dirty.

Has anyone tried this approach for reaching other founders?

Author: Altruistic_Formal765