How to send messages to a WhatsApp group in Java

Using the WhatsMate WA Gateway REST API

This article shows you how to send a message to a WhatsApp group in Java.

You MUST obtain the secret gateway number by signing up for a Forever Green account before you can send a message to a WhatsApp group. Instructions are available on the official site.

To send a WhatsApp group message from your Java application, do this:

  1. Create a new group with a unique name. The API won’t work if it’s not unique.
    • Create a new WhatsApp group

  2. Add the secret gateway to the group.
    • Name the WhatsApp group

  3. Say “Hi” to the group to let the gateway recognize the new group.
  4. Copy the following source code to a Java file named
  5. Customize the TODO lines in the Java program:
    • Specify your gateway instance ID on line 9.
    • Specify your Client ID and Client secret on lines 10 and 11.
    • Specify the group admin number (i.e. your WhatsApp number including the country code) on line 18.
    • Specify the group name (e.g. Happy Club) on line 19.
    • Specify the content of the message on line 20.
  6. Compile the Java file: javac
  7. Execute the class to send your message: java WhatsappSender

As mentioned at the beginning of this tutorial, you will need a trial account to call the above API. Go sign up now.

Happy coding :)