I do not save numbers any more.
You can send a Whatsapp message to a valid international number without the need to save a contact. The API link looks like this
whatsapp://send/?phone=90873737777
So here is a quick JavaScript, in a quick HTML file:
<script>
const url = "whatsapp://send/?phone=";
function phone() {
// get number, append, and browse to whatsapp://send/?phone=number
// PS you can also add "&text=" parameter
const phone = document.querySelector("#phone");
let val = phone.value;
// clean up
val = val.replace(/[^\d]/gi, '');
const _phone = url + val;
document.location.href = _phone;
}
</script>
<input type="text" id="phone" placeholder="Phone">
<button onclick="phone()">Send</button>
This will open WhatsApp on desktop, or on mobile if it exists, with the phone number as the chat window. You can actually message yourself.
Deployed via the beautiful Surge.sh
PS: I could not find reference for that on WhatsApp Docs website, no idea why. Can you?