schema-registry VS kafka-avro-without-registry

So, is JR yet another faking library written in Go? Yes and no. JR indeed implements most of the APIs in fakerjs and Go fake it, but it's also able to stream data directly to stdout, Kafka, Redis and more (Elastic and MongoDB coming). JR can talk directly to Confluent Schema Registry, manage json-schema and Avro schemas, easily maintain coherence and referential integrity. If you need more than what is OOTB in JR, you can also easily pipe your data streams to other cli tools like kcat thanks to its flexibility.

Check here for more details. https://github.com/confluentinc/schema-registry

Confluent Schema Registry for Apache Kafka [GitHub]

So that means we can configure the Kafka producer and consumer with an imaginary schema registry url, that only needs to start with “mock://” and you automatically get to work with the MockSchemaRegistryClient. This way you don't need to explicitly initiate the MockSchemaRegistryClient and configure everything accordingly. That also eradicates the need for the Confluent Schema Registry Container. Running the Kafka Testcontainer with the embedded Zookeeper, we no longer need an extra Zookeeper container and we are down to one Testcontainer for the messaging. This way I ended up with only two Testcontainers: Kafka and the database.

Confluent is a company founded by the creators of Apache Kafka. They are providing the Confluent Platform which consists of several components, all based on Kafka. The license for these components vary. The Schema Registry has the community-license, which basically means it's free to use as long as you don't offer the Schema Registry itself as a SaaS solution. The source code can be found on Github.

Schema Registry from Confluent (GitHub) => http://localhost:8081/

When you check on the internet for testing in the context of Spring Boot Kafka consumer and Avro schema, you find quite a few variants: using the MockSchemaRegistryClient, or writing your own custom Avro de-/serializers, or setting up a Testcontainers ecosystem with a Kafka, a Zookeeper and a Confluent Schema Registry, or using the EmbeddedKafka provided by Spring in the spring-kafka-test dependency.