Karapace

Input—per 1M tokens

Output—per 1M tokens

Context—tokens

WeightsClosed

About

Karapace is ranked #3 of 22 in contract testing tools on Inferse. It runs on API, Self-hosted. There is a free plan.

Compared on contract testing tools

Free plan: Yeskarapace.io
Contract formats: Avro, JSON Schema, Protobufkarapace.io
Consumer verification: Nokarapace.io
Provider verification: Nokarapace.io
Contract registry: Yeskarapace.io
AsyncAPI support: Nokarapace.io
GraphQL support: Nokarapace.io
Self-hosted deployment: Yeskarapace.io

Facts

Purpose: Karapace is a free and open-source implementation of the Kafka Schema Registry and Kafka REST Proxy.karapace.io · 30 Sept 2026
Schema registry: Its Schema Registry stores schemas centrally, maintains version histories, and checks compatibility between versions.karapace.io · 30 Sept 2026
Schema formats: Karapace supports Avro, JSON Schema, and Protobuf schemas.karapace.io · 30 Sept 2026
REST proxy: The REST Proxy provides HTTP APIs for producing and consuming Kafka events and performing administrative operations.aiven.io · 30 Sept 2026
Kafka compatibility: Karapace implements the Confluent Schema Registry API and Confluent REST Proxy API v1 and v2, with v2 as the default.karapace.io · 30 Sept 2026
High availability: A leader/replica architecture provides high availability and load balancing across instances.karapace.io · 30 Sept 2026
Observability: Karapace exposes Prometheus-native metrics and integrates with OpenTelemetry for traces and metrics.karapace.io · 30 Sept 2026
Authentication: Schema Registry authentication supports HTTP basic authentication and OAuth2/OIDC bearer-token validation.karapace.io · 30 Sept 2026
OAuth token handling: The REST Proxy forwards OAuth2 tokens to Kafka and the Schema Registry instead of validating them itself.karapace.io · 30 Sept 2026
Installation: Karapace requires Python 3.12 or newer and can be installed from Docker images or source.karapace.io · 30 Sept 2026
Service endpoints: The Docker setup exposes the Schema Registry on port 8081 and the REST Proxy on port 8082 by default.karapace.io · 30 Sept 2026
Schema references: Avro schema references are supported from Karapace version 6.1.0 onward, while JSON Schema does not support references in the documented table.aiven.io · 30 Sept 2026
Normalization limit: Schema normalization is currently supported for Protobuf only, and Karapace does not implement every Confluent Schema Registry normalization feature.karapace.io · 30 Sept 2026
Monitoring integration: Sentry error reporting can be enabled with the sentry configuration key or the SENTRY_DSN environment variable.karapace.io · 30 Sept 2026
Maker relationship: Aiven describes Karapace as an Aiven-built open-source Schema Registry and REST Proxy for Aiven for Apache Kafka.aiven.io · 30 Sept 2026