I don't understand using Google if WhatsApp API are alive, and how to use it. No documentation, no links, no tutorials. Only articles about "WhatsAPP API won't be public".
What's the truth?
Straight answer to your question is, there is no publicly available WhatsApp API. It is because WhatsApp Inc does not offer its propriety instant messenger as open-source.
But if you are really interested you can check Yowsup library or'WhatsApp-purple' and another reverse engineered library available in GIT
Hope its helpful for you