I have usecase to start using Kafka and was looking for opensource free (production) kafka.
When check Confluent 7.1 platform looks suitable as it has zookeeper / kafka / schema registry / kafka UI bundled together.
Before deciding to go ahead with it just want to check if the Confluent Platform 7.1 is free and open source? Am I required to purchase licensing or paid support?
The Confluent Community License covers several components of Confluent Platform, including KSQLDB, the Schema Registry, REST Proxy, and various Kafka Connect plugins. Confluent Control Center (what you call Kafka UI) is only available on a trial basis, outside of which requires Enterprise license payment.
Majority of Confluent Platform individual components are "source-available", and free with limitations. Many of the plugin features like RBAC, Tiered Storage, Cluster Linking, and server-side Kafka record Schema Validation require payment. This is an Enterprise license and also includes Control Center, on-call Support, and several other connectors.
Apache Kafka, it's clients, and Zookeeper are Apache 2.0 licensed.
If you want a completely Apache 2.0 stack, you can replace Confluent Schema Registry with Apicurio and replace Control Center with various Kafka GUI projects that exist on Github, such as AKHQ or CMAK