Call Adapters

Retrofit is pluggable allowing different execution mechanisms and their libraries to be used for performing the HTTP call. This allows API requests to seamlessly compose with any existing threading model and/or task framework in the rest of your app.

These are called call adapters, and Retrofit includes a few first-party modules for popular frameworks:

• RxJava Observable & Single - com.squareup.retrofit2:adapter-rxjava
• RxJava2 Observable, Flowable, Single, Completable & Maybe - com.squareup.retrofit2:adapter-rxjava2
• RxJava3 Observable, Flowable, Single, Completable & Maybe - com.squareup.retrofit2:adapter-rxjava3
• Guava ListenableFuture - com.squareup.retrofit2:adapter-guava
• Java 8 CompletableFuture - com.squareup.retrofit2:adapter-java8
• [Kotlin suspend functions] - No dependency needed!

Various third-party adapters have been created by the community for other libraries:

• Bolts
• Agera
• Project Reactor