This is the process you need to follow to sign-up:

1.- First thing you need to do is get subscribed (if you are just testing the API there is a free plan that you can choose).

2.- Once subscribed, you need to send a whatsapp text to: +1 (302) 261-2667 including the string: whin
or click on this link to send it automatically: https://wa.me/13022612667?text=whin

3.- You will get a contact card with the active number of whin, and you need to add the card to the contacts on your phone.

4.- Send a whatsapp message from your phone (not from whatsapp web) to the number you just added on #3. The content of the message must be the contact card you just added to your phone. Make sure you send whin’s contact card, any other message will be ignored.

5.- The bot will return a 5 digits code as a response to your whatsapp. You have 30 minutes to POST the code on the /signup endpoint of the API.
If you run out of time, you can request as many codes as you need (just repeat #4).

6.- Once the code is POSTed, the install process is completed and you can start sending/receiving whatsapps on whin API.

You can follow whin channel on whatsapp to receive announcements and upgrades of the platform: https://whatsapp.com/channel/0029VaHwFMpE50Uo5Eu7qe0b

Here is a link to a video with a step by step guide: