There are 4 possible serialization format when using avro:
- Avro Json encoding
- Avro Data Serialization (https://avro.apache.org/docs/current/spec.html#Data+Serialization) Binary format with an header that contains the full schema, this is the format usually used when writing Avro files
- Avro Single Object Encoding (https://avro.apache.org/docs/current/spec.html#single_object_encoding) Binary format with an header with only the fingerprint/id of the schema, this it the format used by Kafka (see this
- Avro Binary Encoding (https://avro.apache.org/docs/current/spec.html#binary_encoding)