CMAK vs Offset Explorer
ComparisonsCMAK vs Offset Explorer, compared
Key takeaway
CMAK is a server-side console deployed once for a team, while Offset Explorer installs on each engineer’s own machine — that is the real difference, not the feature lists. CMAK requires a ZooKeeper connection Kafka 4.0 does not have, and its last release was tagged in April 2022. Offset Explorer is licensed per named user from 139 US dollars, plus 46 a year after the first, and neither tool authenticates a person at all. Kpow by Factor House is licensed per cluster at a published price.
What is CMAK?
CMAK is the Cluster Manager for Apache Kafka, originally Kafka Manager, built at Yahoo and released under Apache 2.0. It is a Scala and Play web application, deployed on a server or in a container, holding a direct connection to a ZooKeeper ensemble. Its scope is that of a Kafka management console rather than a data browser, and there is no commercial distribution, no hosted offering and no paid support tier.
- registering and monitoring several clusters from one view
- creating and modifying topics, and managing partitions
- preferred-replica election and partition reassignment
- optional JMX polling at broker and topic level
The last stable release, 3.0.0.6, was tagged on 29 April 2022, and 3.0.0.5 before it in June 2020, so the silence since continues a cadence that had already stopped. The last commit on master is December 2022 and the last push of any kind is August 2023. There are 522 open issues with nobody triaging them. The repository is public and it is not archived.
What is Offset Explorer?
Offset Explorer is a GUI application for managing and using Apache Kafka clusters, installed on an engineer’s own machine rather than deployed as a service, on Windows, macOS or Linux. It was renamed from Kafka Tool, and the two names are one product. It is built by DB Solo, LLC, licensed per named user, and reaches Apache Kafka 0.11 and above.
- Payloads: rendered as hex or UTF-8, with text pretty-printed as JSON or XML.
- Search: string, binary, Avro, Protobuf, JSON Schema, regular expressions and JsonPath.
- Integrations: Schema Registry, Kafka Connect and ksqlDB, alongside import and export tools.
- Recent versions: 4.0 added Protobuf and OAuth, 4.0.3 added KRaft quorum support, and 4.0.4 added Compare Clusters.
The vendor publishes a change history, and that history carries no date against any version.
What is the official 2026 pricing of CMAK and Offset Explorer?
Offset Explorer is licensed per named user. Personal use is free with no time limit; commercial, educational and non-profit use gets a 30-day evaluation, and after that the published ladder steps the per-seat price down as the count goes up. A machine several people share needs a licence for each person on it. Five engineers is five licences at 139 US dollars each. Fifty is fifty, in the 119 band, plus fifty renewals a year later, and the fifty-first engineer is a purchase order rather than a download.
CMAK charges nothing, and what a team carries instead is the absence of a vendor. Both community deployment paths are now archived and read-only: the Helm chart that was the only Kubernetes route, and the community Docker image. A Kubernetes install therefore runs an unmaintained chart pointing at an unmaintained application, and there is nobody to escalate to when either stops working. The cap on the free side is not money at all. It is which clusters CMAK can address.
Where does each one run out?
CMAK requires a direct ZooKeeper connection. Kafka 4.0, released on 18 March 2025, is the first major release to operate entirely without ZooKeeper, running in KRaft mode by default, so on a KRaft cluster CMAK does not degrade: it cannot connect. MSK, Confluent Cloud, Aiven and Redpanda Cloud either lock down or no longer expose ZooKeeper endpoints, so it is incompatible with most managed Kafka as well.
- Data plane: no message browser, no Schema Registry integration, no Kafka Connect management and no ksqlDB.
- Freshness: reads come from an internal cache rather than live broker APIs, so a reassignment may appear not to have landed.
- Access control: LDAP basic auth and coarse global feature flags, with no per-user, per-cluster or per-topic granularity and no audit log.
- Hardening: enabling ZooKeeper ACLs breaks its connection entirely, so the hardening step and the tool are mutually exclusive.
Offset Explorer is a desktop application, and the structural consequence is the one a platform team meets first. Nothing authenticates a person to the application: the documented authentication covers plaintext, SASL, SSL with a truststore and OAUTHBEARER, all of it client to broker, so the application holds no user identity for a role model or an audit entry to key on.
- Shared record: no shared deployment, no server-side audit log, and no single place to see what an engineer did.
- Configuration: connections are per workstation and travel as exported files, so nothing keeps two engineers in step.
- ACLs: managed in the command line tool rather than the interface.
- Runtime: the Linux build ships no JRE, so Java 21 or later has to be installed first.
Which should you pick?
Pick Offset Explorer if:
- the user is one engineer reading messages on a cluster somebody else runs
- the payload formats are awkward and the search has to cover Protobuf and JsonPath
- an operation configured once in a GUI should be repeatable from a shell
Keep CMAK, with a date on it, if:
- the cluster is ZooKeeper-era
- the daily work is partition reassignment and preferred-replica election
- the migration date is already in a plan somebody owns
Two cases come back neither. A platform team of five to fifty that needs one shared view gets a shared deployment nobody maintains, or fifty copies of a personal tool each with its own connection list. A regulated environment that needs per-topic access control and an audit trail gets global feature flags behind LDAP basic auth with no audit log, or a tool with no user identity to attach a control to. On a KRaft cluster the two capabilities that actually have to be replaced are partition reassignment and preferred-replica election, and neither product covers them there.
Kpow: one shared view with an audit trail
Neither of these gives a regulated environment what it actually needs: per-topic access control and an audit trail. CMAK’s LDAP integration is basic auth behind coarse global feature flags, with no per-topic granularity and no audit log, and Offset Explorer has no user identity at all to attach a control to — its documented authentication is client to broker, and a shared workstation has no server-side record of who did what. Kpow by Factor House sits on top of the cluster rather than running it, deployed as a single stateless container with no external database, sidecar or persistent volume, against self-managed Kafka, MSK, Confluent Cloud, Redpanda, Aiven or Instaclustr. It is licensed per cluster at a published price, so adding another engineer never changes what the team pays.
One shared view an auditor can actually query beats fifty personal connection lists. Kpow’s product page lays out the published price next to both of these.
Sources
- Apache Kafka 4.0.0 release announcement
- Apache Kafka documentation on authorization and ACLs
- Apache Kafka documentation on basic cluster operations