Messaging has changed quite a bit over the years. There was a point in time when text message was the only way to message but online messengers like WhatsApp, Facebook Messenger, Viber, Slack, Disccord, Telegram, etc., have changed things. It’s gotten to a point where messenger apps like WhatsApp even have business accounts for those that need it. It’s unlikely that a person doesn’t use the service but if you need to check if a number is on WhatsApp, it’s pretty easy. The app has a built-in check for it.
Check number on WhatsApp
Copy the number you want to check to your clipboard. Open WhatsApp and tap on the new message button. When you go to the New Chat screen, you have the option to add a new contact. Tap the New Contact button and in the number field, enter the number you want to check.
If the number is not connected to a WhatsApp account, you will see a ‘Not on WhatsApp’ message under it. There’s not much you can do about it. You can use an old fashion text message and let the owner of the number know which app you prefer for everyday conversation.
It goes without saying that anyone with your phone number can also look up whether or not you use WhatsApp. Beyond that though, there is no information that can be discovered. Your name, location, activity status, and any stories that you’ve posted will all be private until you exchange messages with a number.
This may be a slight security risk though for users who don’t want their app usage to be discovered. This also tends to give away if a user has the app installed on their phone. If the app isn’t installed on a phone, it may not count as an active user. Checking if a user is on WhatsApp with this method doesn’t alert them to the fact.
If you proceed to add the number as a contact, they will not know that you did so. It’s only when you send them a message will they be made aware that you have their phone number. The message will also reveal your name and your profile picture if it’s set to public. After that, the person you contacted can message you back and you will both be able to see the others name, profile picture, active status, stories, etc.
In no way does WhatsApp allow a contact to read conversations that you have had with other people.
Source = “https://www.addictivetips.com/ios/check-if-a-number-is-on-whatsapp/”