AxonOps Schema Registry vs WarpStream BYOC Schema Registry

AxonOps Schema Registry is a free, Apache 2.0-licensed service for managing Apache Kafka schemas as an API-compatible replacement for Confluent Schema Registry. It handles Avro, Protobuf, and JSON Schema, including references and seven compatibility modes. Schemas can be stored in PostgreSQL, MySQL, or Cassandra, without requiring Kafka as the storage backend. The project says existing Confluent serializers and Java, Go, and Python Kafka clients can connect by changing the registry URL. Security options include Basic Auth, API keys, JWT, LDAP/AD, OIDC, mTLS, four RBAC roles, rate limiting, and TLS certificate auto-reload. Audit events can go to stdout, files, syslog, or webhooks. Client-side field encryption supports DEK/KEK registries and HashiCorp Vault or OpenBao Transit. Data contracts add metadata and rules. A beta MCP server supports several AI clients. It runs self-hosted on Linux, as a Docker container, or from source.

WarpStream BYOC Schema Registry stores and serves schemas for Kafka records through a REST server compatible with Confluent’s Schema Registry API. It supports Avro and protobuf, while WarpStream Agents validate records and can reject invalid data or emit metrics. The stateless, zero-disk registry stores schemas in the customer’s object storage, and WarpStream says they remain in that cloud account. Schema Linking migrates schemas from a Confluent-compatible registry while preserving IDs and compatibility rules. Authentication options include Basic Authentication, TLS and mutual TLS. Customers create a Schema Registry Virtual Cluster in the console or API, then deploy an agent using the Kafka Agents binary; agents emit logs and metrics. Each registry allows 100,000 schema versions and each schema 1 MB, with support-requested increases. Plans are Dev at $0.03 a month, Fundamentals at 0.17 USD, Pro at 0.52 USD, and Enterprise with no listed price. Cluster minutes use 15-minute billing intervals.