Hello friends, In this post, I will show how to send mail with GMail using OAuth2.0 in Android. This Project contains a lot of steps like Permission, Google Play Service check to do. So, please download the project to perform GMail API completely. First of All, we have to generate OAuth key in Google API Console . To Generate OAuth Key , use your SHA1 key and your app's Package Name as in your Manifest.Paste Following code in your Command Prompt to get SHA1 key in Windows keytool -list -v -keystore "%USERPROFILE%\.android\debug.keystore" -alias androiddebugkey -storepass android -keypass android Project Structure Create a new Project in Android Studio with the required Specifications. AndroidManifest.xml Don't forget to add the following permission in your manifest file. <uses-permission android:name="android.permission.INTERNET"/> <uses-permission android:name="android.permission.GET_ACCOUNTS"/> <!--Added for Accessing External ...