Hacker News Reader

Also curious – I looked up my own company and was surprised that it had pretty accurate data on our own team, as far as location. Not everyone on the team has LinkedIn or any other obvious source they could pull from.

https://www.producthunt.com/posts/remotehub

From the comments it looks like he's doing some of the data lookup manually, looking at twitter and so on.

A guess for my company is stack overflow company profile and/or job postings. The tech stack listed is, I believe, exactly what we list there.