For every developer who uses advertisements in his/her applications Don't risk that invalid traffic caused by your own devices is subtracted. It can lead even to suspending your ads account! Generate the Test Device ID for Ads for your own phone and add it as a test device. Generate the Test Device ID for Ads for any phone/tablet by providing its AndroidID. Hit the share button or long-press to copy the ID out of the application. Example of use of the DeviceID and adding it as test device: val requestBuilder = AdRequest.Builder().addTestDevice("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX") If you found any discrepancy between the Device ID generated by the app and the Device ID that you expect for your device, please let me know! I have done a lot of testing of the algorithm. In case it doesn't work for your phone/tablet, I will be happy to fix it for you and any future user of the application. Just hit the envelope above and send me an email with the details. Thank you!