https://techcrunch.com/2017/11/30/google-datally-data-saver/

Google’s newest app for emerging markets is a service that helps control data usage on a smartphone and get more for your top-up credit.

Datally, which is available for Android devices worldwide from today, applies granular control to enable a user to monitor use of data on their phone and cut data usage on any app as they please. The app design is simple and it appears to be effective. A pilot test in the Philippines gained 500,000 users who typically saved 30 percent of their data plan using the app.