React Native : target with hash string 'android-X' not found

Your $ANDROID_HOME should point to /usr/local/android-sdk and it would be the parent directory of platforms and platform-tools

Gradle will try to locate tools dir in the following location: $ANDROID_HOME/platform/android-23 so verify that you have your tools installed there if the android-23 folder is not present inside $ANDROID_HOME/platform/ , please install Android 6.0 (API23)

You need to point ANDROID_HOME to the parent directory of platforms and platform-tools so /usr/local/Cellar/android-sdk

What I did was to change the target my application was compiled against. To do this edit the file android/app/build.gradle on your project and modify the following:

compileSdkVersion 24
buildToolsVersion "24.0.2"

This should match whatever you have installed without requiring to download another API version.