Do you want to get notified when number becomes online for WhatsApp? Of course you do! :)
whatsTrackeris a professional online last seen analysis tool for online tracking.

During the tracking time you will be able to know how long he/she was online how many times he/she has logged in and out.
Even if his/her last seen is disabled you can still track and see it instantly and receive notifications.
You can also see how much time he/she was online in a day.

WhatsTracker App features

* Multi number tracking
* Instant notification
* Detailed statistics
* Last seen times
* Online durations
* Blocked number tracking

Disclaimer: This app is not affiliated to WhatsAppâ„¢.