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SPECIFICTION
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Karapace

aiven.io

From $35/mo Free plan LinuxAPISelf-hosted
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Spec score 8.1 #8 of 26 in Schema Registry Software

What it is

Karapace is Aiven’s open-source Schema Registry and REST Proxy for Aiven for Apache Kafka. The registry stores and versions schemas, then checks compatibility before a changed schema is published. It accepts Avro, Protobuf, and JSON Schema, with references supported for Avro and Protobuf. Compatibility modes include NONE, BACKWARD, BACKWARD_TRANSITIVE, FORWARD, FORWARD_TRANSITIVE, FULL, and FULL_TRANSITIVE. The REST Proxy exposes HTTP endpoints for producing and consuming Kafka events, so scripts, curl, and HTTP services can work with events. OAuth 2.0/OIDC authentication is available for both components. Registry ACLs and OIDC role-based rules can limit operations, including by HTTP method. Example identity providers include Auth0, Okta, Google Identity Platform, and Azure. Deployment documentation covers Docker and installation from source with pip; the API is stated to support Schema Registry 6.1.1 operations. Karapace is available in Aiven’s Kafka free tier for learning, prototyping, and evaluation. The Free plan costs nothing, while Developer costs $35 a month.

Spec sheet

What it does
Karapace is an Aiven-built open-source Schema Registry and REST Proxy for Aiven for Apache Kafka.Read 2 Oct 2026 · aiven.io
Deployment
The project documents Docker-based setup and installation from source with pip.Read 2 Oct 2026 · github.com
Integrations
The Aiven Terraform Provider supports managing Karapace Schema Registry authorization ACL entries.Read 2 Oct 2026 · aiven.io
Headquarters
Helsinki, FinlandRead 28 Sep 2026 · aiven.io
Founded
2016Read 28 Sep 2026 · aiven.io
Authentication
Karapace supports OAuth 2.0/OIDC authentication for Schema Registry and the REST Proxy.Read 2 Oct 2026 · aiven.io
Authorization
Schema Registry authorization uses access control lists, and OIDC role-based authorization can restrict operations by HTTP method.Read 2 Oct 2026 · aiven.io
Company headquarters
Aiven says it is headquartered in Helsinki, Finland.Read 2 Oct 2026 · aiven.io
Compatibility
The project states that Karapace is compatible with Schema Registry 6.1.1 at the API level and supports all operations in that API.Read 2 Oct 2026 · github.com
Free tier scope
Aiven’s Kafka free tier includes Karapace Schema Registry and is described as intended for learning, prototyping, and evaluation.Read 2 Oct 2026 · aiven.io
HTTP access
The REST Proxy exposes APIs for producing and consuming Kafka events over HTTP, including use from scripts, curl, and HTTP-based services.Read 2 Oct 2026 · aiven.io
Identity providers
The OAuth/OIDC setup documentation lists Auth0, Okta, Google Identity Platform, and Azure as example compliant providers.Read 2 Oct 2026 · aiven.io
Notable limit
Karapace’s built-in schema backup functionality was removed in version 6.0.0 and is no longer maintained in the project.Read 2 Oct 2026 · github.com
Schema management
The Schema Registry stores and versions schemas and can check compatibility before changes are published.Read 2 Oct 2026 · aiven.io
Supported formats
Karapace supports Avro, Protobuf, and JSON Schema registration; schema references are supported for Avro and Protobuf.Read 2 Oct 2026 · aiven.io

Plans and prices

Free Free $0/month Up to 250 KiB/s throughput · retention up to 3 days · up to 5 topics, each with two partitions · Schema Registry and REST proxy included Read 2 Oct 2026 · aiven.io
Developer $35 a month $35/month; $0.04/hour Up to 1 MB/s throughput · retention up to 3 days · up to 20 topics (max 100 partitions) · Schema Registry and REST proxy included Read 2 Oct 2026 · aiven.io

Every Karapace plan and price →

Strong points and limits

Strong points

  • Stores, versions, and validates schema compatibility
  • Supports Avro, Protobuf, and JSON Schema
  • Produces and consumes events through HTTP
  • OAuth 2.0/OIDC authentication for both services
  • Docker and pip installation paths

Limits

  • Built-in schema backup was removed in version 6.0.0
  • Free tier limits throughput, retention, and topics
  • Developer plan costs $35 a month

Who it suits

Karapace suits Kafka users who need schema governance and HTTP event access in self-hosted or hybrid deployments. It is also relevant for teams using OAuth/OIDC controls and Aiven’s Kafka plans.

Verdict

Karapace covers schema lifecycle management and REST-based Kafka access with multiple formats and authorization options. The free tier is bounded, and its former built-in schema backup is no longer maintained.

Where Specifiction places it

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