Karapace

What Karapace is

Karapace is a free, open-source implementation of the Kafka Schema Registry and Kafka REST Proxy. Its Schema Registry stores Avro, JSON Schema, and Protobuf schemas centrally, keeps their version histories, and checks compatibility between versions. The REST Proxy supplies HTTP APIs for producing and consuming Kafka events and carrying out administrative operations. Karapace implements the Confluent Schema Registry API and REST Proxy API versions 1 and 2, with version 2 as the default. Its leader-and-replica architecture supports high availability and load balancing across instances. For observability, it exposes Prometheus-native metrics and integrates with OpenTelemetry for traces and metrics; Sentry error reporting can also be enabled. Schema Registry authentication supports HTTP basic authentication and OAuth2/OIDC bearer-token validation. The REST Proxy forwards OAuth2 tokens to Kafka and the Schema Registry instead of validating them. Karapace is self-hosted, requires Python 3.12 or newer, and can be installed from Docker images or source. The default Docker setup exposes the Schema Registry on port 8081 and REST Proxy on port 8082.