The language apps that use Tandem partners are HelloTalk, or Tandem.
Learn Tandem partners on Tandem
Tandem is a free platform with a simple premise: there is probably someone out there who is learning your native language, and whose native language you want to learn. So they put you in touch with them.
When you sign up, Tandem will review your application to make sure their platform remains safe and that the person you get matched with is also a keen language learner.
HelloTalk is a language learning app that allows users to communicate with others in different languages. It has both a free and premium version, and offers a variety of features to help users learn new languages.