HelloTalk Language Exchange App (Free)

HelloTalk is a really nice app which is geared strongly towards language exchange. The detailed search settings and profiles help you find language partners who will match with you well, for example people who live near you or whose language level is the same as yours.

There are also a lot of helpful features to help your language exchange. You can save messages, provide corrections for each other (which is a really nice way to point out corrections without interrupting your conversation), and translate or hear an audio reading of messages. 

They also provide free calls and all the other features of a good free chat app, just with a focus on language exchange which makes it one of the best apps I’ve used.