Observable.fromCallable(() -> { // ... return response; }) .subscribeOn(Schedulers.io()) .observeOn(AndroidSchedulers.mainThread()) .subscribe(response -> { }); Observable.fromCallable(() -> { // ... return result; }) .subscribeOn(Schedulers.io()) .observeOn(AndroidSchedulers.mainThread()) .subscribe(result -> { }); RxView.clicks(button) .throttleFirst(500, TimeUnit.MILLISECONDS) .observeOn(AndroidSchedulers.mainThread()) .subscribe(event -> { }); Observable<Integer> task1 = Observable.fromCallable(() -> { // ... return result1; }); Observable<Integer> task2 = Observable.fromCallable(() -> { // ... return result2; }); Observable.zip(task1, task2, (result1, result2) -> { // ... return finalResult; }) .subscribeOn(Schedulers.io()) .observeOn(AndroidSchedulers.mainThread()) .subscribe(result -> { }); dependencies { // RxAndroid implementation 'io.reactivex.rxjava3:rxandroid:3.x.x' // RxJava implementation 'io.reactivex.rxjava3:rxjava:3.x.x' }