HelloTalk is a chat app that pairs people who are learning each-other's languages. You ake a profile, set your native language and the language you're learning (and indicate your level out of five) and then you can browse profiles of people whose native and target languages mirror yours.
It's sort of similar to lang-8, in that the app itself only serves as a platform, and you interact with other users. Some of them may have an agenda or try to sell you private tutoring, but ideally you'll end up in situations like scotcheggz where you just have a nice conversation and correct each others mistakes.
I haven't used it since last winter, but at that time
I found that most chat partners tapered off after the self-introductions and such were finished up. I'm sure that if you put more time into it and try to strike up a ton of conversations you'll eventually find something though.
All in all, definitely not a bad app, or a scam in any way. Recommended for people who have never really had a chance to chat in Japanese.