Reminders to send messages only
The app works well. However, it does not automatically send messages but rather sets reminders to do them. You type recipient and content of the WhatsApp message in the app. Then you schedule the reminder. Once you acknowledge the alarm of the reminder, whatsapp opens and you just need to push the button to send the message prepared beforehand. I did not try if it worked with group chats but likely does not. One week trial. Then, there are monthly or annual subscription plans.