Custom apk Android

Please read well we need professional dev
Very smart and understanding

we need a good knowledge with accessibility service and intents with extras to build an app to be linked to a web panel to send messages through WhatsApp on Android devices .
we don't need any third party APIs, we just wanted to open intent in WhatsApp with message data and phone number and media if exist, then the app automatically click the send button and check whether the message is sent or not ..