I use switchy to do analytics and retargeting of conversations to whatsapp. The link is created perfectly, it works great.

But in the case of whatsapp, the user (who clicks on the link), is directed to a link that includes the + sign in the url, by doing this whatsapp is able to start the conversation but you do not see the profile picture of the recipient.

Without the + sign, if the profile picture is seen and the profile picture impacts conversions.

Switchy is one ascii character away from being perfect.