Tools/apache/kafka

Kafka

Distributed event streaming platform

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The Lens

By Erik Loyd, SaaS CEO and former COO/CFO of an AWS Premier Partner.

Updated Oct 2026

Kafka is the event backbone a lot of large companies run on: services write events to it, other services read them, and Kafka keeps the ordered history on disk so new consumers can replay from any point. Apache 2.0 and completely free. Connect and Streams ship in the box, but most of the Postgres, S3 and Elasticsearch connectors people mean come from third parties.

Kafka 4.0 removed ZooKeeper, so KRaft is the only mode and a whole second cluster is gone. Still on ZooKeeper mode? Migrate to KRaft on 3.x before any 4.x upgrade. Production still means several brokers, disk planning and someone who understands partitions and consumer groups.

The money goes to managed hosting. Confluent Cloud Basic starts at $0 with the first eCKU free, then $0.05/GB in or out; Standard starts around $385/month. Amazon MSK runs $0.21/hour per kafka.m5.large broker, about $469/month for three before storage. Solo: you probably don't need Kafka. Small teams: managed. Larger teams with platform engineers: self-host.

The catch: without the scale, you pay the complexity tax for nothing. Watch the auth code too: 4.1.0 and 4.1.1 accepted any unsigned JWT under OAUTHBEARER by default (CVE-2026-33557). Need a simple queue? RabbitMQ or NATS.

Free vs Self-Hosted vs Paid

fully free

Free: Apache Kafka is Apache 2.0 with no paid edition. Current supported releases are 4.3.1 (June 25, 2026), 4.2.2 and 4.1.2, with 4.4.0 in release candidates. You get the brokers, KRaft metadata, the Kafka Connect runtime, Kafka Streams, MirrorMaker 2 and the Java client. The repo ships only file and MirrorMaker connectors; the Postgres, S3 and Elasticsearch connectors come from third parties with their own licenses.

Self-hosted: Binaries plus official Docker images (apache/kafka, apache/kafka-native). KRaft only since 4.0 (March 18, 2025): ZooKeeper-mode clusters must migrate to KRaft before upgrading, and KRaft clusters older than 3.3 should go to 3.9.x first. Your cost is VMs, disks and the person who understands rebalancing, which is the real line item.

Paid: No paid Kafka from Apache; you pay a managed host. Confluent Cloud (pay as you go, priced per hour and per GB): Basic starts at $0/month, first eCKU free then $0.14/eCKU-hour, $0.05/GB in or out, $0.08/GB-month stored, 99.5% SLA, 5 TB storage cap. Standard starts around $385/month ($0.75/eCKU-hour, $0.035 to $0.050/GB). Enterprise starts around $895/month for private networking. Confluent's monthly estimates assume 70% utilization. New signups get $400 to spend in their first 30 days. Amazon MSK (US East): provisioned Standard brokers at $0.21/hour per kafka.m5.large ($0.204 for m7g.large) plus $0.10/GB-month storage, so three m5.large brokers are $468.72/month before storage; Express brokers at $0.408/hour per m7g.large plus $0.01/GB written; MSK Serverless at $0.75/cluster-hour ($558.00 for a 31-day month) plus $0.0015/partition-hour and data charges.

Kafka itself is free under Apache 2.0. The real bill is ops time or a managed host: Confluent Cloud Standard starts around $385/month and three MSK m5.large brokers run $468.72/month before storage.

What to do by team size

Solo: free to run locally for learning, but for real work a simpler queue like RabbitMQ or NATS is less to babysit
Small team: managed: Confluent Cloud Basic (first eCKU free, $0.05/GB in or out) rather than self-hosting
Medium team: managed unless someone on staff knows Kafka: Confluent Standard from about $385/month or three MSK m5.large brokers at $468.72/month before storage
Large team: free self-hosted on KRaft with a platform team, or Confluent Enterprise from about $895/month for private networking

Self-hosting ops:heavy

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