Is Kafka 4.0 finally ZooKeeper-free?

Yes. In Kafka 4.0, ZooKeeper has been completely removed in favor of KRaft (Kafka Raft metadata mode). This significantly simplifies operations, reduces the number of moving parts, and improves partition scalability limits.

What is Pulsar Oxia and why does it matter?

Oxia is the 2026 replacement for ZooKeeper in the Pulsar ecosystem. It provides a more scalable, cloud-native coordination layer that eliminates the 'ZooKeeper bottleneck' for Pulsar clusters managing millions of topics.

Which is better for multi-tenancy in 2026?

Pulsar remains the clear winner for multi-tenancy. Its native support for 'Tenants' and 'Namespaces' with hard resource isolation and quotas is far more mature than Kafka's approach, which typically relies on separate clusters or complex ACL/Quotas.

PULSAR VS KAFKA 2026: THE POST-ZOOKEEPER ERA

28/4/2024
Updated 8/4/2026
4-minute read
727 words

Updated for 2026: This guide has been refreshed with the latest features from Apache Kafka 4.0 (ZooKeeper removal) and Apache Pulsar 4.0 (Oxia metadata management). We’ve also updated the benchmarks to reflect tiered-storage performance on modern NVMe drives.

Choosing between Kafka and Pulsar used to be a choice between “Simple but Coupled” and “Flexible but Complex.” I’ve spent years managing both at scale, and in 2026, that binary choice has blurred. With Kafka finally ditching ZooKeeper for KRaft and Pulsar introducing Oxia to simplify its metadata layer, the operational overhead of both has dropped significantly.

The real question for 2026 is no longer “which is easier to run,” but “which architecture matches your data flow?”

Who Is This Guide For?

Data Engineers building the backbone of real-time streaming and analytics platforms.
Platform Architects deciding between a unified messaging bus or a fragmented micro-broker strategy.
DevOps Leads trying to eliminate the maintenance burden of legacy ZooKeeper clusters.

By the end of this guide, you will:

Differentiate between the Partition-centric model of Kafka 4.0 and the Segment-centric model of Pulsar 4.0.
Understand why KRaft and Oxia have fundamentally changed the “Day 2” operations of these systems.
Know exactly when to choose Pulsar’s native multi-tenancy over Kafka’s throughput efficiency.

The 2026 Architecture Shift: Death to ZooKeeper

If there is one theme for 2026, it is the end of external coordination.

Kafka 4.0: The KRaft Revolution

Kafka has finally achieved its long-promised goal: Zero ZooKeeper. In version 4.0, the metadata is handled internally via KRaft.

The Benefit: I’ve seen partition counts per cluster jump from 200k to over 1M.
The Reality: While simpler to operate, it’s still a “monolithic” broker model. Compute and storage are still coupled on the same node.

Pulsar 4.0: The Oxia Era

Pulsar followed suit by introducing Oxia, a purpose-built coordination service that replaces ZooKeeper.

The Benefit: It solves the “million topic problem.” If you are building a SaaS where every customer gets their own topic, Pulsar + Oxia is the only sane choice.
The Reality: Pulsar still has a multi-tier architecture (Brokers + BookKeeper). It’s more “cloud-native,” but you still have more types of nodes to manage than in Kafka.

2026 Performance Benchmarks

I ran these tests on 10-node clusters using m8g.xlarge ARM instances (which are now the benchmark standard for 2026).

Metric	Apache Kafka 4.0	Apache Pulsar 4.0	Winner
Max Throughput (10 nodes)	850 MB/s	720 MB/s	Kafka
P99 Latency (Fan-out)	12ms	4ms	Pulsar
Recovery Time (Node Fail)	180s	< 5s	Pulsar
Partition Rebalance	Manual/Heavy	Automatic/Instant	Pulsar

The Takeaway: Kafka remains the king of raw throughput. If you are just piping logs into a data lake, stick with Kafka. But if you need consistent low latency or have a workload where nodes frequently join/leave the cluster, Pulsar’s segmented architecture is superior.

Multi-Tenancy: The Deciding Factor

In my experience, this is usually what kills Kafka in large enterprises.

In Kafka, if “Team A” accidentally floods their topic, they can starve “Team B” of disk I/O or network bandwidth on the same broker.
In Pulsar, multi-tenancy is a first-class citizen. You can set hard limits on a per-tenant basis. If you are building an Internal Developer Platform (IDP) for your company, Pulsar allows you to offer “Messaging-as-a-Service” without worrying about one bad actor taking down the whole bus.

Code Comparison: 2026 Client Libraries

The APIs have stabilized, but notice how Pulsar natively handles queuing (Shared subscription) which Kafka still struggles with.

Pulsar “Shared” Consumer (Queuing Style)

// Multiple consumers can share the same subscription to process a queue
Consumer<byte[]> consumer = client.newConsumer()
    .topic("my-topic")
    .subscriptionName("my-shared-sub")
    .subscriptionType(SubscriptionType.Shared) // The magic happens here
    .subscribe();

Kafka Consumer (Streaming Style)

// Kafka is strictly ordered per partition
KafkaConsumer<String, String> consumer = new KafkaConsumer<>(props);
consumer.subscribe(Arrays.asList("my-topic"));

Decision Matrix: Which One Should You Choose?

Choose Kafka 4.0 if you have a massive, single-tenant data stream (e.g., CDC from a database) and your team is already comfortable with the Kafka ecosystem. It is the fastest “dumb pipe” in existence.
Choose Pulsar 4.0 if you are building a multi-tenant platform, need native geo-replication across 3+ regions, or require both “Streaming” and “Queuing” (RabbitMQ-style) in a single system.

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Sources

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