Data Monitor — Open Source Productivity App

Data Monitor is a user-friendly, free and open source app for you to manage your data usage. Data Monitor helps you to accurately measure your daily data traffic, and analyze the data in a way easy to understand.

Features:

• Track daily data usage
• App-wise data usage stats
• Stats for different time period (last month, this year, all time etc)
• Mobile data as well as Wifi usage stats
• Weekly data usage overview
• Data Monitor widget and notification
• Data usage alert
• Custom mobile data reset time
• Network diagnostics
• Live network speed monitor (Beta)
• App usage time
• No ads or In-app purchases
• Light-weight and Open Source

Source:

https://github.com/itsdrnoob/DataMonitor