I was looking for a compounding medicine and all compounding pharmacies asked me to send the recipe via Whatsapp. There are a few ways that I can start a conversation in Whatsapp: (1) add a contact, which exposes my privacy in social networks; (2) using a URL based "API" to directly call the number, it's a lot of typing and error prone.
So I created an MVP, a simple web page, to solve my own problem. All this happened on a Friday, kept working and polishing my MVP and launched the first version on Sunday.