Awesome
Open in WhatsApp 
- This app uses WhatsApp public api 'click to chat' feature to open a chat with any number without saving to your phone book.
- You can create an url link that will open WhatsApp on the specified number. This is a WhatsApp feature, you don't need this app to open the link, only to create it.
Download
<img src="https://f-droid.org/badge/get-it-on.png" alt="Get it on F-Droid" height="80">
Thanks
- ialokim for android-phone-number-field which is license under Apache-2.0,