Requirement : Sending data from an android app or iOS app to big data ecosystem using Kafka and store it for real time analysis or near real time.
1- How to send data from Android App to Kafka (Is rest API only options)? Or we can connect to the kafka with App directly.
There is a REST Proxy for Kafka, so you can send messages over HTTP from your mobile app directly to Kafka, and from there process them further in Kafka, route them to Hadoop, etc etc.
Disclaimer: I work for Confluent, who lead the development of the open-source REST proxy