How does everyone "pull comps"?

[Kyle Soudalan]

Whenever someone analyzes a deal, I hear them say "I pulled comps on this area". I understand that to mean they took a look at comparable properties in the location of the potential deal. But how does everyone do this? Type in the address into Zillow, Redfin, etc. and look at the nearby, similar homes listed?

I could understand this for individual investors, but what do bigger investors do? What do brokerages do? Is any entity bigger than an individual investor using special software to scalably pull comparable properties in a particular area that then aggregates the unstructured data, make it structured, and then run it through some template to better analyze whether it's a good deal?

And what is their primary source for such tools? Zillow has pretty stringest anti-scraping system, so are they paying big software firms to do this scraping? Or are they partnered with dozens of RE agents who give easy access to the MLS with a custom API to quickly "pull comps"?

I would love if someone here who understands the ins-and-outs of how bigger RE players run comps walk us through this entire process and how it's done.