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Karapace
Helsinki, Finland
What it is
Karapace is an open-source Schema Registry and REST Proxy built by Aiven for Aiven for Apache Kafka. The registry stores and versions schemas and can check compatibility before changes are published. It supports Avro, Protobuf, and JSON Schema, with schema references for Avro and Protobuf. Its REST Proxy provides HTTP APIs for producing and consuming Kafka events, including use from scripts, curl, and HTTP-based services. Both components support OAuth 2.0/OIDC authentication. Registry authorization uses access control lists, and OIDC role-based authorization can restrict operations by HTTP method. The project documents Docker setup and installation from source with pip. It states that Karapace is API-level compatible with Schema Registry 6.1.1 and supports all operations in that API. Aiven's Kafka free tier includes the registry and proxy; the Free plan is free, with throughput up to 250 KiB/s, retention up to three days, and up to five topics with two partitions each. The Developer plan is $35 a month. Built-in schema backup was removed in version 6.0.0 and is no longer maintained in the project.
For and against
For
- Stores and versions schemas with compatibility checks.
- Supports Avro, Protobuf, and JSON Schema.
- REST Proxy exposes HTTP APIs for Kafka events.
- Supports OAuth 2.0/OIDC authentication.
- Documents Docker setup and pip installation.
Against
- Built-in schema backup was removed in version 6.0.0.
- The listed Free plan limits throughput to 250 KiB/s.
- Free plan retention is limited to three days.
- Free plan allows up to five topics.
The verdict
Karapace combines schema handling and an HTTP proxy with authentication and authorization controls. Note the free tier’s listed capacity limits and that built-in schema backup is no longer maintained.
Who it suits
Karapace may suit teams using Aiven for Apache Kafka that need schema management or HTTP access to Kafka events. The free tier is described as intended for learning, prototyping, and evaluation.
Plans and prices
Free
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
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
On the record
- Authentication
- Karapace supports OAuth 2.0/OIDC authentication for Schema Registry and the REST Proxy.aiven.io · read 2 Oct 2026
- Authorization
- Schema Registry authorization uses access control lists, and OIDC role-based authorization can restrict operations by HTTP method.aiven.io · read 2 Oct 2026
- Company headquarters
- Aiven says it is headquartered in Helsinki, Finland.aiven.io · read 2 Oct 2026
- 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.github.com · read 2 Oct 2026
- Deployment
- The project documents Docker-based setup and installation from source with pip.github.com · read 2 Oct 2026
- Free tier scope
- Aiven’s Kafka free tier includes Karapace Schema Registry and is described as intended for learning, prototyping, and evaluation.aiven.io · read 2 Oct 2026
- HTTP access
- The REST Proxy exposes APIs for producing and consuming Kafka events over HTTP, including use from scripts, curl, and HTTP-based services.aiven.io · read 2 Oct 2026
- Identity providers
- The OAuth/OIDC setup documentation lists Auth0, Okta, Google Identity Platform, and Azure as example compliant providers.aiven.io · read 2 Oct 2026
- Integrations
- The Aiven Terraform Provider supports managing Karapace Schema Registry authorization ACL entries.aiven.io · read 2 Oct 2026
- Notable limit
- Karapace’s built-in schema backup functionality was removed in version 6.0.0 and is no longer maintained in the project.github.com · read 2 Oct 2026
- Schema management
- The Schema Registry stores and versions schemas and can check compatibility before changes are published.aiven.io · read 2 Oct 2026
- Supported formats
- Karapace supports Avro, Protobuf, and JSON Schema registration; schema references are supported for Avro and Protobuf.aiven.io · read 2 Oct 2026
- What it does
- Karapace is an Aiven-built open-source Schema Registry and REST Proxy for Aiven for Apache Kafka.aiven.io · read 2 Oct 2026
