Aiven is ending support for Confluent Schema Registry and REST proxy when Kafka v2.8 reaches end of life (EOL) on April 26th 2022.

Customers using this software component will be required to switch to Karapace, our drop-in open source alternative, before upgrading to Kafka v3.0 or newer.

Upon EOL of Kafka v2.8, existing Kafka clusters on v2.8 that use Confluent Schema Registry will be automatically switched to Karapace as part of the upgrade to the latest available version of Kafka.


Since the launch of Aiven for Apache Kafka in 2016, Confluent Schema Registry and REST proxy has been an integral part of our offering.

On December 14, 2018, Confluent changed the licensing of some components of the Confluent platform to the Confluent Community License, which forbids third parties to use such components in competing SaaS products. With this change, Aiven for Apache Kafka customers no longer receive updates on this component and have been on version 5.0.3 since then.

To ensure that we can continue offering well-maintained and supported open source technologies to our customers, Aiven has since invested in building a drop-in, open source replacement for Kafka REST and Schema Registry called Karapace.

Karapace has been production-ready and available by default on Kafka clusters since January 2020. It is already in active use by the vast majority of our Kafka customer base.


Karapace is compatible with Schema Registry 6.1.1 on the API level and supports all operations in the API. We have done our best to ensure 1:1 compatibility between Confluent Schema Registry and Karapace, including the error messages. However, there may be some discrepancies. If you encounter any issue that is critical for your applications, get in touch with us at or open a github issue.

Karapace vs Confluent Schema Registry

In comparison to Confluent Schema Registry 5.0.3, Karapace offers the following new capabilities.

  • JSON schema support along with Avro.

  • A new REST endpoint GET /schemas/ids/{int: id}/versions for listing every subject in which a given schema is registered and its corresponding version.

  • Permanently delete schemas to reclaim storage space with a permanent flag on DELETE /subjects/(string: subject)?permanent=true and DELETE /subjects/(string: subject)/versions/(versionId: version)?permanent=true.

Features that are not yet supported in Karapace are:

  • SASL & SSL authentication

  • ACLs

We are committed to the development of Karapace to meet your business needs.

Support for SASL authentication and ACLs is in our roadmap. We'll keep you posted on our progress.

Switching to Karapace

If your Kafka service is using either Confluent Schema Registry or Kafka REST, a notification banner describing the upgrade process will appear in the service overview page.

Clicking Switch to Karapace will prompt you to confirm the transition to using Karapace.

This operation does not require any new service nodes. After clicking Migrate, your service will be using Karapace.

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