How to "INTEGRATE GOOGLE SIGN_IN into YOUR ANDROID APP" STEP 1) Make sure in your SDK manager Google repository and google play services Tools -> ANDROID - > SDK manager -> Launch StandAlone SDK manager -> Extras STEP 2) GET CONFIGURATION FILE https://developers.google.com/mobile/add?platform=android&cntapi=signin&cnturl=https:%2F%2Fdevelopers.google.com%2Fidentity%2Fsign-in%2Fandroid%2Fsign-in%3Fconfigured%3Dtrue&cntlbl=Continue%20Adding%20Sign-In Enter Project name , Package and select your country Now, Select Google sign in. COPY SHAI certificate code by typing, in CMD "keytool -list -v -keystore C:\Users\YOURUSERPROFILENAME\.android\debug.keystore -alias androiddebugkey -storepass android -keypass android" (WITHOUT QUOTES) Follow next easy steps.! STEP 3)Download .json FILE And paste it to APP directory..!! STEP 4)Put this dependecies : PASTE in APP LEVEL "buid.gradle" file:" apply pl