Best tools for Kafka schema registry management
ComparisonsSchema 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.
At a glance
Ten options are scored here on this page's five weighted criteria, 70 points in all. The rubric is weighted: RBAC on register and delete counts three times, and Avro, Protobuf and JSON Schema, Check before registering, Version diff and Multiple registries count once. The five listed first, of ten, each out of 70: Kpow 58, which takes its best score on Multiple registries (10 out of 10) and its lowest on Check before registering (5 out of 10); Apicurio Registry 55, Licence: Apache 2.0; Kafbat UI 49, Licence: Apache 2.0; Confluent Control Center 43, Licence: Confluent Enterprise licence; AWS Glue Schema Registry 42, Price: Free to use.
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, Factor House’s 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, Factor House’s co-founder and CEO, has had to switch a subject in one of Factor House’s 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.
| Rank | Tool | Type | Formats | Compatibility check before registering | Version diff | Multiple registries | RBAC on register and delete | Source |
|---|---|---|---|---|---|---|---|---|
| 1 | 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 |
| 2 | 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 |
| 3 | 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 |
| 4 | 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) |
| 5 | 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 |
| 6 | 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) |
| 7 | 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) |
| 8 | 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 |
| 9 | 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 |
| 10 | 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.
Rank 1 Kpow
58 out of 70 Total
Try Kpow in the live demo No signup needed.
- 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 ×3 weight, this criterion counts 3 times toward the total
- 9 out of 10
Why these scores for Kpow
- Avro, Protobuf and JSON Schema 8 out of 10
- It handles Avro, Protobuf and JSON Schema, for creating subjects and for decoding records in data inspect.
- Check before registering 5 out of 10
- It validates schemas in the UI and makes per-subject compatibility editable, but the compatibility rule itself runs only at registration, and there is no CI goal. The page’s own prose says it falls short of Apicurio and the Maven plugin here.
- Version diff 8 out of 10
- A visual version diff ships in both editions.
- Multiple registries 10 out of 10
- The page’s summary calls it “the only UI here that manages several registries of different kinds against one Kafka cluster”, and the FAQ repeats it.
- RBAC on register and delete 9 out of 10
- Create, edit-version and delete are separate actions on Enterprise only, each can require admin approval, and that matches the criterion’s register versus delete split.
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.
Staying patched. Kpow’s release notes name the CVEs each release remediates, and the 96.4 image built on 5 August 2026 bundles 311 dependencies of which one carries a high or critical advisory, none of them published before that release. That is not a claim to patch faster than a community project: Kpow’s own dependency remediation has run from 14 to 128 days, and the current image still ships CVE-2026-75595 in netty, a 9.1 critical public since 19 August 2026, unpatched. What a licence buys here is not a different deployment model, because Kpow is self-hosted too. It is a company contracted to ship the fix. Every dependency figure on this page was read on 24 September 2026 from the published artefacts and from nvd.nist.gov.
Compare Kpow vs Kafbat UIKpow vs AKHQKpow vs Confluent Control CenterKpow vs Redpanda Console
Rank 2 Apicurio Registry
55 out of 70 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 ×3 weight, this criterion counts 3 times toward the total
- 9 out of 10
Why these scores for Apicurio Registry
- Avro, Protobuf and JSON Schema 9 out of 10
- It covers Avro, Protobuf, JSON Schema plus OpenAPI, AsyncAPI and other artifact types, the widest on the page.
- Check before registering 9 out of 10
- Dry-run flag on the native API and a Maven test-update goal; prose says it beats Kpow on the pre-registration dry run, and the FAQ calls it the strongest free choice for pre-registration dry runs.
- Version diff 8 out of 10
- Yes, the web UI compares two versions.
- Multiple registries 2 out of 10
- It is one registry per deployment.
- RBAC on register and delete 9 out of 10
- The page’s own prose calls it “the strongest free registry for access control”, with admin, write and read-only roles and owner-only updates, and it is not 10 because it is off by default.
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.
Staying patched. Apicurio Registry is Apache-2.0, actively developed, with a published security policy and three CVEs, all XML-parsing flaws disclosed together in June 2026: CVE-2026-12975, CVE-2026-12992 and CVE-2026-12993. Sixty-plus releases, last pushed 23 September 2026.
Rank 3 Kafbat UI
49 out of 70 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 ×3 weight, this criterion counts 3 times toward the total
- 8 out of 10
Why these scores for Kafbat UI
- Avro, Protobuf and JSON Schema 8 out of 10
- Avro, Protobuf and JSON Schema are all supported.
- Check before registering 6 out of 10
- Its API has a compatibility check endpoint, with global and per-subject settings, found in its API contract rather than its prose docs. It scores above Kpow and below the registries.
- Version diff 7 out of 10
- A diff view exists in the UI source, not described in its prose docs.
- Multiple registries 4 out of 10
- It manages one registry per Kafka cluster, with extra registries only as deserializers, and many clusters per install.
- RBAC on register and delete 8 out of 10
- View, create, edit, delete and global compatibility permissions are all free.
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.
Staying patched. Kafbat UI released v1.5.0 in April 2026 and has not shipped since. In the 157 days since, at least 20 high or critical advisories have been published against libraries that release bundles, including the same netty critical CVE-2026-75595 that the current Kpow image carries. Only 150 of its 266 bundled jars resolved to a Maven coordinate, so that count is a floor and the state of the release itself is unmeasured. Kafbat does publish a security policy, which AKHQ and Kafdrop do not, and the one CVE filed against its own code, CVE-2025-49127, was already fixed in the release that preceded the advisory. Six releases in two years.
Compare Kpow vs Kafbat UIAKHQ vs Kafbat UIConfluent Control Center vs Kafbat UIKafbat UI review
Confluent Control Center
confluent.io
43 out of 70 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 ×3 weight, this criterion counts 3 times toward the total
- 6 out of 10
Why these scores for Confluent Control Center
- Avro, Protobuf and JSON Schema 8 out of 10
- Avro, Protobuf and JSON Schema all work, whatever the Confluent registry holds.
- Check before registering 6 out of 10
- It shows an error when an edited schema is incompatible, which is a real compatibility check at edit time, and there is no CI step. It scores above Kpow, whose UI check is schema validation.
- Version diff 8 out of 10
- A version diff check box sits in the schema view, and the page’s summary lists it among the tools with a diff.
- Multiple registries 3 out of 10
- It is scoped to Confluent Platform, and its docs say nothing about registries outside it.
- RBAC on register and delete 6 out of 10
- Access control comes through Confluent Platform RBAC, and granularity is not described on the page.
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.
Compare Kpow vs Confluent Control CenterAKHQ vs Confluent Control CenterConfluent Control Center vs Kafbat UIConfluent Control Center review
AWS Glue Schema Registry
42 out of 70 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 ×3 weight, this criterion counts 3 times toward the total
- 6 out of 10
Why these scores for AWS Glue Schema Registry
- Avro, Protobuf and JSON Schema 8 out of 10
- It covers Avro, Protobuf (proto2 and proto3) and JSON Schema.
- Check before registering 2 out of 10
- There is no dry run, the validity check is syntax only, and compatibility is enforced only at registration, with no documented default mode.
- Version diff 8 out of 10
- GetSchemaVersionsDiff returns a JsonPatch diff between versions, and the criterion accepts an API that returns one.
- Multiple registries 6 out of 10
- Many registries run per AWS account, all of the Glue type.
- RBAC on register and delete 6 out of 10
- IAM policies cover it, and the page does not describe register versus delete granularity.
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.
Rank 6 AKHQ
41 out of 70 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 ×3 weight, this criterion counts 3 times toward the total
- 8 out of 10
Why these scores for AKHQ
- Avro, Protobuf and JSON Schema 8 out of 10
- It handles Avro, Protobuf and JSON Schema, per its schema model in source.
- Check before registering 4 out of 10
- A compatibility test in the source covers Avro schemas only, and it trails on Protobuf and JSON Schema compatibility testing.
- Version diff 1 out of 10
- No version diff is documented.
- Multiple registries 4 out of 10
- It manages one registry per cluster connection, Confluent or TIBCO, with Glue for decoding only.
- RBAC on register and delete 8 out of 10
- Read, create, update, delete and delete-version actions on schemas are all free.
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.
Staying patched. AKHQ has no CVE filed against its own code, and that is the wrong number to plan against. Release 0.28.0, cut on 6 August 2026, bundles 270 libraries and 18 of them carry a high or critical advisory. Sixteen were already public, with fixed versions already on Maven Central, on the day it shipped, and five are netty advisories Kpow had remediated three weeks earlier in 96.2: CVE-2026-44249, CVE-2026-45416, CVE-2026-45674, CVE-2026-47691 and CVE-2026-50010. The oldest has been open 108 days. That is exposure and remediation latency rather than a working attack, and every figure resolves against the published jar and nvd.nist.gov. Four releases in two years, and no security policy at any path GitHub reads.
Compare Kpow vs AKHQAKHQ vs Kafbat UIAKHQ vs Confluent Control CenterAKHQ review
Confluent Schema Registry
confluent.io
38 out of 70 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 ×3 weight, this criterion counts 3 times toward the total
- 6 out of 10
Why these scores for Confluent Schema Registry
- Avro, Protobuf and JSON Schema 8 out of 10
- It supports Avro, Protobuf and JSON Schema out of the box.
- Check before registering 9 out of 10
- The page’s summary says its REST endpoints “win outright”, and POST /compatibility tests a candidate before registering, with the mode set per subject. The Maven plugin scores 10 for the CI step.
- Version diff 1 out of 10
- The REST API docs have no diff endpoint, and not documented scores 1, not 0.
- Multiple registries 2 out of 10
- One registry runs per deployment, and it is the server.
- RBAC on register and delete 6 out of 10
- RBAC exists, but it needs a commercial licence through the Security Plugins, and the page does not describe register versus delete granularity.
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.
Redpanda schema registry
redpanda.com
37 out of 70 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 ×3 weight, this criterion counts 3 times toward the total
- 6 out of 10
Why these scores for Redpanda schema registry
- Avro, Protobuf and JSON Schema 8 out of 10
- Avro, Protobuf and JSON Schema are all supported.
- Check before registering 8 out of 10
- It serves a Confluent-style compatibility endpoint with a default of BACKWARD.
- Version diff 1 out of 10
- No version diff is documented, and its Console page lists no diff.
- Multiple registries 2 out of 10
- One registry runs per Redpanda cluster.
- RBAC on register and delete 6 out of 10
- Authorization exists but needs an enterprise licence, and granularity is not described on the page.
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.
Rank 9 Karapace
34 out of 70 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 ×3 weight, this criterion counts 3 times toward the total
- 5 out of 10
Why these scores for Karapace
- Avro, Protobuf and JSON Schema 8 out of 10
- Avro, Protobuf and JSON Schema are all supported.
- Check before registering 8 out of 10
- It serves a Confluent-compatible compatibility endpoint with a default of BACKWARD, where transitive modes check all previous schemas.
- Version diff 1 out of 10
- No version diff is documented.
- Multiple registries 2 out of 10
- It is one registry per deployment.
- RBAC on register and delete 5 out of 10
- Access is a file of Read or Write grants per subject pattern, and Write includes deleting versions, so register and delete are not separate permissions.
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.
Staying patched. Karapace is Apache-2.0 under Aiven, with a published security policy. Two CVEs, and on both the fixed release was out on or before the day the advisory was published: 5.0.2 for CVE-2025-61673 in October 2025 and 6.0.0 for CVE-2026-29190 in March 2026. More than sixty releases, last pushed 23 September 2026.
The registry's REST API, Maven plugin and CLI
docs.confluent.io
29 out of 70 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 weight, this criterion counts 3 times toward the total
- 3 out of 10
Why these scores for The registry's REST API, Maven plugin and CLI
- Avro, Protobuf and JSON Schema 8 out of 10
- It covers whatever the registry supports, which for the Confluent registry is all three formats.
- Check before registering 10 out of 10
- It is “the strongest option for CI”, and the page’s summary says it wins outright because it fails a pull request before a schema reaches any registry.
- Version diff 0 out of 10
- There is no diff, and the page’s own prose says “Neither produces a diff”.
- Multiple registries 2 out of 10
- It reaches one registry per invocation.
- RBAC on register and delete 3 out of 10
- Access control is whatever the registry enforces, and the page’s own prose says it gives operators nothing for access control.
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.
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 demoFAQ
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.
How these tools were scored
Every option is scored from 0 to 10 on each criterion, from the evidence and sources this page cites, and the reason for each score is on its card. The criteria are weighted: Avro, Protobuf and JSON Schema counts once, Check before registering counts once, Version diff counts once, Multiple registries counts once and RBAC on register and delete counts three times, for a total out of 70. RBAC on register and delete counts three times here, because deleting a schema version breaks every consumer still reading records written against it, and registering a bad one does the same going forward. Format coverage, checking before registering, version diff and multiple registries count once. This page is published by Factor House, which makes Kpow. Every option is scored on the same rubric and the same sources: Kpow's per-criterion scores are set the same way as every other option's and are not adjusted, and the weights apply to every option alike. Kpow ranks first on its total of 58 out of 70. The other options follow by total.