Use kafka-avro-console-producer with a schema already in the schema registry

For the current version of the CLI tool

kafka-avro-console-producer \
 --broker-list <broker-list> \
 --topic <topic>  \
 --property schema.registry.url=http://localhost:8081 \
 --property value.schema.id=419

For older version

You'll need to extract the schema from the API request using jq, for example

value.schema="$(curl http://localhost:8081/schemas/ids/419 | jq -r .schema)"

You can use the property value.schema.id:

kafka-avro-console-producer \
 --broker-list <broker-list> \
 --topic <topic>  \
 --property schema.registry.url=http://localhost:8081 \
 --property value.schema.id=419