If I add a number to WhatsApp, will that person be notified - briefly?
When you add a contact's phone number to your WhatsApp contacts, the individual is not automatically notified of this action. They will only become aware if they manually check their WhatsApp contacts or if you initiate a conversation with them.
If I add a number to WhatsApp, will that person be notified - in detail?
When you add a contact's phone number to your WhatsApp contacts list, the individual associated with that number is not automatically notified. This process simply involves updating your personal address book within the application and does not trigger any alerts or messages to the other party.
WhatsApp relies on having the user's phone number stored in both parties' contact lists to facilitate communication. When you add a new number, it only becomes visible to you unless that person also has your number saved in their contacts list. This is because WhatsApp uses the contacts in your phone’s address book to determine which of your contacts are using WhatsApp and can be messaged.
To establish contact with someone on WhatsApp, both parties must have each other's numbers stored in their respective devices. Once this mutual saving occurs, WhatsApp can recognize the connection and enable messaging between the two users. Until then, no notification is sent to the other person indicating that they have been added to your contacts list.
In summary, adding a number to your WhatsApp contacts does not result in any form of notification being sent to the person associated with that number. Communication can only begin once both parties have each other’s numbers saved in their respective contact lists.