Amazon Pinpoint journeys now include the ability to pass data into a custom channel, and be able to perform a yes/no or multivariate split based on the response. Journeys in Amazon Pinpoint were designed for customers who want to send targeted communications that drive high-value user actions. Journeys can include custom channel activities, which can be used to send messages through channels that Amazon Pinpoint doesn’t support natively, such as WhatsApp or Signal.
Source:: Amazon AWS