I'm an Android developer, how can I integrate WhatsApp with my app?

There are two ways to integrate with WhatsApp:
-Through a custom URL scheme
-Through Android's intent system.

Custom URL Scheme

WhatsApp provides a custom URL scheme to interact with WhatsApp:
If you have a website and want to open a WhatsApp chat with a pre-filled message, you can use our custom URL scheme to do so. Opening whatsapp://send?text= followed by the text to send, will open WhatsApp, allow the user to choose a contact, and pre-fill the input field with the specified text.
Here is an example of how to write this on your website:
Hello, world!

Android intent system

Like most social apps on Android, WhatsApp listens to intents to share media and text. Simply create an intent to share text, for example, and WhatsApp will be displayed by the system picker:
Intent sendIntent = new Intent(); sendIntent.setAction(Intent.ACTION_SEND); sendIntent.putExtra(Intent.EXTRA_TEXT, "This is my text to send."); sendIntent.setType("text/plain"); startActivity(sendIntent);
However, if you prefer to share directly to WhatsApp and bypass the system picker, you can do so by using setPackage in your intent:
This would simply be set right before you call startActivity(sendIntent);
Similarly you can use Android's intent system to send media through WhatsApp, once again, using setPackage to restrict the package to WhatsApp if you only want to send to WhatsApp. Check this developer page for more information.

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