Ask HN: How does the following apps work behind the scenes?

1 pointZeeshanAK1 comment

Ask HN: How does the following apps work behind the scenes? 1. http://heedzy.com/ 2. https://reviewcommand.co/ 3. https://feedcheck.co/

I know there's a Google play API which lets you get reviews for the apps you own but how then the aforementioned apps get all reviews for other apps?