What is the "Label API" used for?

The Label API can be used to provide post-back data to re-classify transactions, which have already been reviewed by SEON. 

It automatically changes the states of transactions, so you can use it to feed the authorization codes from the issuers, and chargeback information. You can set Negative and Positive labels on the Settings page for the Label API to use.

Labelling is also useful for the Machine Learning algorithm since it learns from the feedback that you provide.