Like4like Apps

Are they against Instagram's ToS?

I was reading a previous thread on this, but everyone had differing opinions. I can't seem to see any definitive answers from Instagram or other websites either.

The apps I'm referencing are those which you like other users photos to build up an in-app currency, then use said currency to feature your own specific image and gather likes from other users. I've been thinking about using this method more to boost specific posts that perform under average and appear irregular on my feed.

What are your thoughts?

They are against tos, there are many of these followlikers on the store but new ones get a system interference rejection