Best tools for Kafka schema registry management

Q: How do I check schema compatibility before registering?

Call the registry's compatibility endpoint, POST /compatibility/subjects/ /versions/latest, with the candidate schema, or run the Maven plugin's test-compatibility goal in CI so an incompatible schema fails the build. AWS Glue has no equivalent dry run and enforces compatibility only at registration.

Comparisons

Chad Harris·September 22, 2026·16 min read

Schema registry management is two jobs: running a registry that stores and version-checks your Avro, Protobuf and JSON Schema contracts, and operating it day to day, which means registering versions safely, seeing what changed, and controlling who can change or delete what. The registries are Confluent Schema Registry, Apicurio Registry, Karapace, AWS Glue Schema Registry and Redpanda’s built-in registry. The management layer on top is the registry’s own REST API, Maven plugin and CLI, Confluent Control Center, and the Kafka UIs that include a schema view: Kpow, Kafbat UI and AKHQ. Kpow is Factor House’s product, and I work at Factor House as a Solutions Architect, so it is scored on the same rubric and the same sources as every other option.

What to look for in a schema registry tool

Five criteria separate a registry setup that protects consumers from one that only stores schemas. Every option below is scored against them, in this order.

Formats: Avro, Protobuf and JSON Schema. Most organisations end up with more than one format, usually Avro from the data platform team, Protobuf from service teams, and JSON Schema from whoever got there first. A tool that handles only Avro manages part of the contracts and leaves the rest to guesswork. The same applies to reading the data: when Kpow added automatic serializer detection in data inspect, Tom Crowley, our founding engineer, noted at the time that customers moving over from another tool had specifically asked for it, because working out which deserializer a topic needs is real, repeated work.

Compatibility checks before a version is registered, per subject. Every registry checks compatibility when a version is registered. The question is whether you can run that check earlier, in a pull request or from a UI before you commit, and whether the mode can be set per subject rather than only globally. The mode only protects consumers when it matches your deploy order. BACKWARD is safe when consumers deploy first, FORWARD when producers do, and FULL either way. Subjects drift from the setting you intended, too. Derek Troy-West, our co-founder and CEO, has had to switch a subject in one of our own environments back to backward compatibility after it had been changed. A mismatched mode shows up in production as consumers failing on records the registry accepted.

A diff between versions. In a compatibility incident, the first question is what changed between version N and version N+1. Without a diff, someone downloads two JSON documents and compares them by eye while consumers are failing. A diff in the UI, or an API that returns one, makes that a thirty-second job.

Multiple registries at once. Registries multiply: one per environment, one per business unit, a Confluent registry next to an Apicurio one during a migration, AWS Glue for the MSK clusters. A tool that manages one registry per install leaves you with one tab per registry. How the tool reads the registry matters at scale too. When Tom moved Kpow to a single-call observation mode, a registry with more than 4,500 schemas went from roughly 12,000 network calls per snapshot to about seven, after a customer reported that the older per-schema mode had taken down their registry deployment.

RBAC on who can register and delete. Registering a new version and deleting a subject are different risks, and a good tool treats them as different permissions. In 2024 Kpow split its original schema edit permission into separate edit-version and delete actions. A registry that anyone with network access can write to is one bad curl away from a deleted subject, and a permanent delete removes schema IDs that consumers still need to read older records. The wider comparison of Kafka RBAC tools covers role models beyond the registry, and tools to control destructive Kafka operations covers approval steps for deletes like this one.

The options, compared

The first five rows are registries, and the rest manage a registry you already run. Several teams run one of each. Cells describe what each tool’s own documentation or source says, and “not documented” means it does not appear in the tool’s own material.

Tool	Type	Formats	Compatibility check before registering	Version diff	Multiple registries	RBAC on register and delete	Source
Confluent Schema Registry	Registry, Confluent Community License	Avro, Protobuf and JSON Schema	Yes, a REST endpoint tests a schema against a subject version. Default mode is BACKWARD, settable per subject	No diff endpoint in the REST API docs	One registry per deployment, it is the server	Yes, but RBAC needs a commercial licence through the Security Plugins	Confluent docs: Schema Evolution, API reference, Licensing (text only)
Confluent Control Center	Management UI, Confluent Enterprise licence	Avro, Protobuf and JSON Schema	Shows an error when an edited schema is incompatible	Yes, a version diff check box in the schema view	Scoped to Confluent Platform	Through Confluent Platform RBAC	Confluent docs: Control Center, Manage Schemas (text only)
Apicurio Registry	Registry, Apache 2.0	Avro, Protobuf, JSON Schema, plus OpenAPI, AsyncAPI and others	Yes, a dry-run flag on the REST API and a Maven test-update goal. No rules apply unless configured, except the Confluent-compatible API, which defaults to BACKWARD	Yes, in the web UI	One per deployment	Yes, open source admin, write and read-only roles, optional owner-only updates, off by default	Apicurio docs
Karapace	Registry, Apache 2.0	Avro, Protobuf and JSON Schema	Yes, Confluent-compatible compatibility endpoint. Default BACKWARD in its config source	Not documented	One per deployment	Yes, a file-based Read or Write grant per subject pattern	Karapace on GitHub
AWS Glue Schema Registry	Managed AWS registry, free to use	Avro, Protobuf and JSON Schema	No dry run. The validity check is syntax only, and compatibility is enforced when a version is registered. No documented default mode	Yes, an API returns a JsonPatch diff between versions	Many registries per AWS account	Yes, through IAM policies	AWS Glue docs
Redpanda schema registry	Registry built into Redpanda, BSL	Avro, Protobuf and JSON Schema	Yes, Confluent-style compatibility endpoint. Default BACKWARD	Not documented	One per Redpanda cluster	Authorization needs an enterprise licence	Redpanda docs: Schema Registry (text only)
Kpow	Management UI and API, commercial with a free Community Edition	Avro, Protobuf and JSON Schema	Schema validation in the UI, and the registry’s per-subject rule runs on every new version. Compatibility is editable per subject. No CI goal	Yes, a visual version diff in both editions	Yes, several registries per Kafka cluster, and Confluent-compatible, Glue, Google, Redpanda and Buf registries (Enterprise for multiple)	Yes, separate create, edit-version and delete actions, with staged approval available (Enterprise)	Kpow docs
Kafbat UI	Management UI, Apache 2.0	Avro, Protobuf and JSON Schema	Yes, a compatibility check endpoint in its API	Yes, a diff view in the UI source	One managed registry per Kafka cluster, extra registries only as deserializers. Many clusters per install	Yes, free: view, create, edit, delete and global compatibility permissions	Kafbat UI docs
AKHQ	Management UI, Apache 2.0	Avro, Protobuf and JSON Schema	Compatibility test in the source, Avro schemas only	Not documented	One registry per cluster connection, Glue for decoding only	Yes, free: read, create, update, delete and delete-version	AKHQ docs
REST API, Maven plugin and CLI	Build and command-line tooling	Whatever the registry supports	Yes, the strongest option for CI: test-compatibility runs before merge	No	One registry per invocation	Whatever the registry enforces	Confluent docs: Schema Registry Maven Plugin (text only)

Here is how the scores work out. For the pre-registration check, the Maven plugin and the registry REST endpoints win outright, because they are the only options that fail a pull request before a schema reaches any registry. For diffs, Kpow, Control Center, Apicurio, Kafbat UI and the Glue API all have one, and Confluent Schema Registry, Karapace, Redpanda and AKHQ do not document one. On multiple registries, Kpow is the only UI here that manages several registries of different kinds against one Kafka cluster, while Kafbat UI and AKHQ manage one registry per cluster. On RBAC, the free UIs (Kafbat UI and AKHQ) and Apicurio include it, while Confluent’s registry, Redpanda’s and Kpow put it behind a paid tier.

Kpow

factorhouse.io

40 out of 50 Total

Listed first because it is our product. Scores are unadjusted.

Type: Management UI and API
Version diff: Community and Enterprise
Multi-registry and RBAC: Enterprise

Avro, Protobuf and JSON Schema: 8 out of 10
Check before registering: 5 out of 10
Version diff: 8 out of 10
Multiple registries: 10 out of 10
RBAC on register and delete: 9 out of 10

What it is. Factor House’s management UI and API for Kafka, which includes a schema registry view. It does not store schemas itself and works with the registries you already run.

Formats. Avro, Protobuf and JSON Schema, for creating subjects and for decoding records in data inspect.

Compatibility and diff. You can update a subject’s compatibility, create new versions and validate schemas in the UI, and the registry’s rule is applied when a version is registered. A visual version diff is included in both Community and Enterprise editions. Kpow has no CI-side check, so it does not replace the Maven plugin in a build pipeline. One trade-off in the default observation mode: compatibility is shown on each schema rather than in the aggregate table.

Multiple registries and access control. Kpow connects to Confluent Schema Registry, Apicurio and Karapace, plus AWS Glue, Google, Redpanda and Buf registries, and supports several registries against one Kafka cluster, configured with SCHEMA_REGISTRY_RESOURCE_IDS (Kpow docs). Multiple registries are an Enterprise feature. RBAC separates SCHEMA_CREATE, SCHEMA_EDIT_VERSION and SCHEMA_DELETE, and any of them can be set to require an admin’s approval before it runs.

Where it leads and where it falls short. It leads on managing mixed registries from one place, with orphaned-subject detection and a view of soft-deleted subjects for cleanup. It falls short of Apicurio and the Maven plugin on pre-registration checks in CI, and RBAC, SSO and multiple registries need the Enterprise licence, from $4,500 per cluster per year.

Source. Kpow schema management docs and Kpow authorization docs.

Compare Kpow vs Kafbat UI Kpow vs AKHQ Kpow vs Confluent Control Center Kpow vs Redpanda Console

Apicurio Registry

apicur.io

37 out of 50 Total

Type: Registry
Licence: Apache 2.0
Default rules: None unless configured

Avro, Protobuf and JSON Schema: 9 out of 10
Check before registering: 9 out of 10
Version diff: 8 out of 10
Multiple registries: 2 out of 10
RBAC on register and delete: 9 out of 10

What it is. An open source registry under Apache 2.0 that implements the Confluent REST API “to provide drop-in compatibility”, alongside its own API.

Formats. Avro, Protobuf and JSON Schema, plus AsyncAPI, OpenAPI and other artifact types.

Compatibility and diff. Apicurio’s native API accepts a dryRun flag that reports whether an operation would succeed without making changes, and its Maven plugin has a test-update goal. One default to know: its rule reference says that if no global rules are configured, no rules are applied, but its Confluent-compatible endpoint defaults to BACKWARD. The web UI can compare the content of two versions.

Multiple registries and access control. It is one registry. Role-based authorization with admin, write and read-only roles is built in and open source, with an option that only an artifact’s creator can update or delete it, and it is disabled by default.

Where it leads and where it falls short. Apicurio beats Kpow on price and on the pre-registration dry run, and it is the strongest free registry for access control. The trap is the wire format: its serdes can write a 4-byte or a legacy 8-byte ID, or put the ID in headers, so mixing Apicurio serdes with Confluent ones needs deliberate configuration.

Source. Apicurio Registry documentation and the Apicurio Registry repository.

Kafbat UI

github.com/kafbat/kafka-ui

33 out of 50 Total

Type: Management UI
Licence: Apache 2.0
Registries: One per Kafka cluster

Avro, Protobuf and JSON Schema: 8 out of 10
Check before registering: 6 out of 10
Version diff: 7 out of 10
Multiple registries: 4 out of 10
RBAC on register and delete: 8 out of 10

What it is. An open source web UI for Apache Kafka, under Apache 2.0.

Formats. Avro, JSON Schema and Protobuf.

Compatibility and diff. Its API contract includes a check-compatibility operation and global and per-subject compatibility settings, and its frontend source has a diff view comparing two versions. Neither is described in its prose docs.

Multiple registries and access control. Kafbat UI manages many Kafka clusters from one install, but each cluster takes a single schema registry address. Extra registries can only be added as deserializers for reading messages, not for schema management. RBAC is free, with schema permissions for view, create, delete, edit and global compatibility changes.

Where it leads and where it falls short. It beats Kpow on price, with RBAC and a diff at no cost. It falls short when you need more than one registry per cluster.

Source. Kafbat UI configuration docs, Kafbat UI RBAC docs and the Kafbat UI repository.

Compare Kpow vs Kafbat UI AKHQ vs Kafbat UI Confluent Control Center vs Kafbat UI Kafbat UI review

Confluent Control Center

confluent.io

31 out of 50 Total

Type: Management UI
Licence: Confluent Enterprise licence

Avro, Protobuf and JSON Schema: 8 out of 10
Check before registering: 6 out of 10
Version diff: 8 out of 10
Multiple registries: 3 out of 10
RBAC on register and delete: 6 out of 10

What it is. Confluent Platform’s management UI, which includes a schema view per topic.

Formats. Whatever the Confluent registry holds: Avro, Protobuf and JSON Schema.

Compatibility and diff. Confluent’s Control Center documentation says an invalid or incompatible schema update shows an error, and that you can “compare versions of a schema” by turning on a version diff check box.

Multiple registries and access control. Access control comes from Confluent Platform. Its documentation describes it as a tool for Kafka “in Confluent Platform”, and says nothing about using it with registries or clusters outside that.

Where it leads and where it falls short. It has a real diff and a compatibility error at edit time. It is licensed under the Confluent Enterprise licence and only makes sense if you already run Confluent Platform.

Source. Confluent documentation: Control Center, Manage Schemas for Topics (named in text, not linked).

Compare Kpow vs Confluent Control Center AKHQ vs Confluent Control Center Confluent Control Center vs Kafbat UI Confluent Control Center review

AWS Glue Schema Registry

docs.aws.amazon.com/glue

30 out of 50 Total

Type: Managed AWS registry
Price: Free to use
Serializers: Its own, not the Confluent API

Avro, Protobuf and JSON Schema: 8 out of 10
Check before registering: 2 out of 10
Version diff: 8 out of 10
Multiple registries: 6 out of 10
RBAC on register and delete: 6 out of 10

What it is. AWS’s managed registry, serverless and free to use, and a common pairing with Amazon MSK. It has its own serializers rather than the Confluent API.

Formats. Avro, JSON Schema and Protobuf (proto2 and proto3).

Compatibility and diff. Glue has eight modes, from NONE and DISABLED to FULL_ALL, and its documentation recommends BACKWARD without stating a default. There is no dry run: its validity check “does not take a schema set name, no compatibility checks are performed”, so compatibility is only enforced at registration. A GetSchemaVersionsDiff API returns the difference between two versions in JsonPatch format.

Multiple registries and access control. You can create as many registries as you need in one account, controlled with IAM policies.

Where it leads and where it falls short. It leads on cost and on a diff API. It falls short on pre-registration checks and on portability, since its serdes and API are its own.

Source. AWS Glue Schema Registry documentation and the Glue schema registry API reference.

Confluent Schema Registry

confluent.io

26 out of 50 Total

Type: Registry
Licence: Confluent Community License
Default mode: BACKWARD, settable per subject

Avro, Protobuf and JSON Schema: 8 out of 10
Check before registering: 9 out of 10
Version diff: 1 out of 10
Multiple registries: 2 out of 10
RBAC on register and delete: 6 out of 10

What it is. The registry most Kafka clients were written against, and the API the others copy. It stores schemas and assigns the schema IDs that go into every registry-encoded record.

Formats. Avro, Protobuf and JSON Schema out of the box, per Confluent’s Schema Registry overview.

Compatibility and diff. A REST endpoint, POST /compatibility/subjects/{subject}/versions/{version}, tests a candidate schema before you register it. Confluent’s schema evolution documentation states the default is BACKWARD, not BACKWARD_TRANSITIVE, and modes can be set per subject. The REST API documentation has no diff endpoint.

Multiple registries and access control. It is one registry. RBAC on subjects is available, but Confluent’s licensing page states that a licence is required for RBAC through the Schema Registry Security Plugins.

Where it leads and where it falls short. It leads on ecosystem: every serializer speaks its API. It falls short on management, with no UI of its own and access control behind a licence. The server is under the Confluent Community License, not Apache 2.0, per its GitHub README.

Source. Confluent documentation: Schema Evolution and Compatibility, Schema Registry API Reference, and Confluent Platform Licenses (named in text, not linked).

Redpanda schema registry

redpanda.com

25 out of 50 Total

Type: Registry built into Redpanda
Licence: Business Source License
Default mode: BACKWARD

Avro, Protobuf and JSON Schema: 8 out of 10
Check before registering: 8 out of 10
Version diff: 1 out of 10
Multiple registries: 2 out of 10
RBAC on register and delete: 6 out of 10

What it is. A registry built into Redpanda brokers, managed from Redpanda Console.

Formats. Avro, Protobuf and JSON.

Compatibility and diff. It serves the compatibility endpoint and defaults to BACKWARD, per Redpanda’s API documentation. Its Console page lists adding a version, changing compatibility and deleting, and no diff.

Multiple registries and access control. One per Redpanda cluster. Redpanda’s schema registry authorization documentation says the feature requires an enterprise licence.

Where it leads and where it falls short. There is no separate service to run if you are already on Redpanda, while access control is paid and the Community Edition is under the Business Source License.

Source. Redpanda documentation: Schema Registry overview, API and authorization pages (named in text, not linked).

Compare Kpow vs Redpanda Console Redpanda Console review

AKHQ

akhq.io

25 out of 50 Total

Type: Management UI
Licence: Apache 2.0
Registries: One per cluster connection

Avro, Protobuf and JSON Schema: 8 out of 10
Check before registering: 4 out of 10
Version diff: 1 out of 10
Multiple registries: 4 out of 10
RBAC on register and delete: 8 out of 10

What it is. An open source web UI for Apache Kafka, under Apache 2.0.

Formats. Avro, JSON Schema and Protobuf, per its schema model in source.

Compatibility and diff. Its repository code has a compatibility test that takes Avro schemas only. No version diff is documented.

Multiple registries and access control. One registry per cluster connection, of type Confluent or TIBCO, with AWS Glue supported for decoding only. RBAC is free, with read, create, update, delete and delete-version actions on schemas.

Where it leads and where it falls short. It is free and widely deployed, and it trails on diffs, on Protobuf and JSON Schema compatibility testing, and on multiple registries.

Source. AKHQ connection docs, AKHQ groups and roles and the AKHQ repository.

Compare Kpow vs AKHQ AKHQ vs Kafbat UI AKHQ vs Confluent Control Center AKHQ review

Karapace

github.com/Aiven-Open/karapace

24 out of 50 Total

Type: Registry
Licence: Apache 2.0
API level: Confluent Schema Registry 6.1.1

Avro, Protobuf and JSON Schema: 8 out of 10
Check before registering: 8 out of 10
Version diff: 1 out of 10
Multiple registries: 2 out of 10
RBAC on register and delete: 5 out of 10

What it is. An Apache 2.0 registry written as a drop-in replacement for Confluent’s, compatible with Schema Registry 6.1.1 at the API level according to its README.

Formats. Avro, JSON Schema and Protobuf.

Compatibility and diff. It serves the Confluent-style compatibility endpoint, and transitive modes check against all previous schemas. Its config source sets BACKWARD as the default. Its own documentation describes no diff.

Multiple registries and access control. It is one registry. Access control is a file of Read or Write grants per subject pattern, where Write includes deleting schema versions.

Where it leads and where it falls short. It is free, simple and compatible with existing clients, but it has no UI, so the management layer has to come from somewhere else.

Source. Karapace README.

The registry's REST API, Maven plugin and CLI

docs.confluent.io

23 out of 50 Total

Type: Build and command-line tooling
Runs in: CI pipelines

Avro, Protobuf and JSON Schema: 8 out of 10
Check before registering: 10 out of 10
Version diff: 0 out of 10
Multiple registries: 2 out of 10
RBAC on register and delete: 3 out of 10

What it is. The do-it-yourself path: the registry’s compatibility endpoint, Confluent’s Schema Registry Maven plugin, and the Confluent CLI’s schema commands.

Formats. Whatever the registry supports.

Compatibility and diff. This is the strongest pre-registration check available. The Maven plugin’s test-compatibility goal reads schemas from the local file system and tests them against the registry, and Confluent’s documentation says it can run in a continuous integration pipeline. The plugin also has validate, register, download, test-local-compatibility and set-compatibility goals. The CLI has confluent schema-registry schema compatibility validate. Neither produces a diff.

Multiple registries and access control. One registry per invocation, with whatever access control the registry enforces.

Where it leads and where it falls short. Every team that publishes schemas should run this in CI whichever UI it picks, Kpow included. It gives operators nothing for day-to-day inspection, cleanup or access control.

Source. Confluent documentation: Schema Registry Maven Plugin and Confluent CLI reference (named in text, not linked).

How Factor House approaches it

Kpow treats the registry as one of several resources attached to a Kafka cluster, next to Connect and ksqlDB, and manages whichever registries you run from the same screen as the topics that use them. From the schema view you can create subjects in Avro, JSON Schema or Protobuf, create new versions, change a subject’s compatibility, compare versions with a visual diff, clean up orphaned subjects whose topics no longer exist, and permanently delete soft-deleted subjects when you are ready to (Kpow docs, schema management).

In an incident, the most useful part is that schema metadata carries through to the data. In Kpow’s data inspect, each record shows its schema ID and deserializer, and records that fail to deserialize can be kept and flagged or listed on their own, so a compatibility break shows up as a count of failing records rather than a stack trace in one consumer’s log. When Kpow runs against several registries, which the guide to integrating Confluent-compatible registries in Kpow sets up with Confluent Schema Registry, Apicurio and Karapace side by side, all of them sit in the same view under the same RBAC.

The test worth running in a Kpow demo is the incident path from this page: open a subject, compare two of its versions in the visual diff, check its compatibility setting, then query the topic to see whether any records fail to deserialize.

If you are here because consumers are already failing, start with the diagnosis instead: how to diagnose a Kafka deserialization error walks the five causes and the proof for each.

Product demo · 1 min

Apache Kafka schema registry management: Kpow demo

Chad Harris walks through schema registry management in Kpow, which connects to Confluent, Karapace, MSK, and other registries: viewing and editing schemas, creating new revisions, updating compatibility settings, and creating or deleting subjects.

Kpow live demo

Browse schemas and versions live

Open the Kpow demo to explore schema subjects and versions next to the topics that use them.

Built for platform and data engineers running Kafka in production.

Try the Kpow demo

FAQ

What is the best schema registry for Kafka?

For most teams on the Confluent client ecosystem, Confluent Schema Registry or a compatible registry such as Apicurio or Karapace, because every serializer speaks that API. Apicurio is the strongest free choice for access control and pre-registration dry runs. On MSK with AWS-native tooling, AWS Glue Schema Registry is free and has a diff API, but uses its own serializers.

Can I manage multiple schema registries from one tool?

Yes. Kpow manages several registries against one Kafka cluster, including mixed types, and many clusters from one install. Kafbat UI and AKHQ manage many clusters but one registry per cluster.

How do I check schema compatibility before registering?

Call the registry’s compatibility endpoint, POST /compatibility/subjects/<subject>/versions/latest, with the candidate schema, or run the Maven plugin’s test-compatibility goal in CI so an incompatible schema fails the build. AWS Glue has no equivalent dry run and enforces compatibility only at registration.

Is Confluent Schema Registry open source?

The server is under the Confluent Community License, with some modules under Apache 2.0, according to its repository README. Apicurio Registry and Karapace are Apache 2.0.

The wider picture of running Kafka in production is in the complete Kafka guide.