Is confluent schema registry "/subjects/{name}" url referring to the topic key or topic value by default?

Question

To my understanding a schema that is registered on confluent schema registry can refer to either they key or the value of a kafka topic.

In this section of Confluent Platform documentation, it says:

With the default TopicNameStrategy, most clients will expect the schema for the record values in mytopic to be registered under the subject mytopic-value

Is the above rule described somewhere in the confluent schema registry specification? Why most clients and not all?

In other words, should I provide some extra information to the consumer, apart from schema registry url, so that they know for sure that the specific url contains the schema of the topic value (and not of the topic key), or whether they will need to append "-value" to the url for getting the actual schema of the topic value?

Answer 1

It's referring to both, but "most clients" do not use complex keys that require schema registry (null, string, integer, etc)

should I provide some extra information to the consumer, apart from schema registry url

Only when you need to use a subject name strategy other than the default, as explained in the documentation

whether they will need to append "-value" to the url for getting the actual schema of the topic value?

That's automatically configured when you've set either of these to Confluent classes

key.deserializer
value.deserializer

If you've ever written your own deserialize function, you'll see that boolean isKey parameter is available to do that logic