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Databases · head to head

Apache Pulsar vs Nebula

Apache Pulsar logo

Apache Pulsar

Databases

Cloud-native messaging and streaming with separated storage

From
Free
Rated
-
Full reviewWebsite
Nebula logo

Nebula

Networking

Certificate based overlay network from Slack, with identity and firewall rules carried in the certificate

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Apache Pulsar more components than Kafka: brokers, BookKeeper and ZooKeeper each need operating; Nebula the open source project has no user interface, no enrolment workflow and no revocation service, so certificate issuing, distribution and expiry become scripts you write and then have to keep working.
  • They diverge on capability: Apache Pulsar covers Separated storage, Nebula covers Certificate carried identity.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Apache Pulsar and Nebula actually diverge.

Attributes where Apache Pulsar and Nebula differ
AttributeApache PulsarNebula
PlatformsLinux, Docker, Kubernetes, Self-hostedLinux, macOS, Windows, iOS, Android, FreeBSD
CategoryDatabasesNetworking

Identical on both: starting price (Free), pricing model (Open source, no licence fee), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Apache Pulsar

  • Separated storage
  • Queuing and streaming
  • Built-in multi-tenancy
  • Geo-replication

Only in Nebula

  • Certificate carried identity
  • Group based host firewall
  • Lighthouse discovery
  • Noise protocol encryption
  • Unsafe routes
  • Managed option

What people use each for

The jobs each tool is most often brought in to do.

Apache Pulsar

  • Platforms needing both work queues and replayable streams without running two systemsnot Nebula
  • Multi-tenant messaging where isolation between teams is a requirementnot Nebula
  • Deployments where storage and traffic grow at genuinely different ratesnot Nebula

Nebula

  • Flattening a network across several clouds and datacentres without VPC peering or route tablesnot Apache Pulsar
  • Very large fleets where a central policy service on the connection path is unacceptablenot Apache Pulsar
  • Environments that already run an internal certificate authority and want the network to use itnot Apache Pulsar
  • Replacing per host iptables rules with policy written against roles that follow the hostnot Apache Pulsar

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Apache Pulsar

  • More components than Kafka: brokers, BookKeeper and ZooKeeper each need operating
  • Correspondingly harder to run well, and the expertise is rarer than Kafka expertise
  • A much smaller ecosystem of connectors, tooling and hiring pool than Kafka
  • The architectural advantages only pay off at a scale most deployments never reach

Nebula

  • The open source project has no user interface, no enrolment workflow and no revocation service, so certificate issuing, distribution and expiry become scripts you write and then have to keep working.
  • Revoking a compromised host means distributing a blocklist entry to every other host and reloading them, which is a fleet wide operation rather than a click, and easy to get wrong under pressure.
  • Changing a host group membership means reissuing and redeploying its certificate, so policy changes are a deployment rather than a configuration edit.
  • There is no identity provider integration or single sign on in the open source version, so it maps well to servers and badly to a fleet of user laptops.
  • NAT traversal is best effort and hosts behind symmetric NAT need a relay configured deliberately, so connectivity failures show up as intermittent rather than immediate and are awkward to diagnose.

Pricing, plan by plan

Apache Pulsar

Free
  • Apache PulsarFree
    • Full functionality
    • No usage limits
    • Community support

Nebula

Free
  • NebulaFree
    • Full functionality under the MIT licence
    • No host limit
    • You operate the certificate authority and lighthouses
  • Defined Networking$undefined/month
    • Hosted control plane and enrolment
    • Managed certificate lifecycle and revocation
    • Policy and DNS interface

Which should you pick?

Choose Apache Pulsar if

  • You need separated storage.
  • You want to start without paying.
  • You work on Linux, Docker, Kubernetes, Self-hosted.
  • You also want queuing and streaming.
Apache Pulsar review

Choose Nebula if

  • You need certificate carried identity.
  • You want to start without paying.
  • You work on Linux, macOS, Windows, iOS, Android, FreeBSD.
  • You also want group based host firewall.
Nebula review

Questions people ask

Is Apache Pulsar or Nebula better?
Neither clearly leads. Apache Pulsar starts at Free and Nebula at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Apache Pulsar or Nebula?
Apache Pulsar starts at Free and Nebula at Free.
Does Apache Pulsar or Nebula run on more platforms?
Apache Pulsar runs on Linux, Docker, Kubernetes, Self-hosted. Nebula runs on Linux, macOS, Windows, iOS, Android, FreeBSD.
Can I use Apache Pulsar for free?
Both have a free tier, so you can try either at no cost before committing.
What is Apache Pulsar best used for?
Apache Pulsar is most often used for platforms needing both work queues and replayable streams without running two systems, multi-tenant messaging where isolation between teams is a requirement, deployments where storage and traffic grow at genuinely different rates. Of those, platforms needing both work queues and replayable streams without running two systems and multi-tenant messaging where isolation between teams is a requirement are not what Nebula is typically brought in for.
What can Apache Pulsar do that Nebula cannot?
Apache Pulsar covers Separated storage, Queuing and streaming, Built-in multi-tenancy, Geo-replication. Nebula covers Certificate carried identity, Group based host firewall, Lighthouse discovery, Noise protocol encryption.

Answered from the vendors’ own pages

Apache Pulsar: Is Apache Pulsar free?

Yes, open source under the Apache Software Foundation.

Nebula: Does it use WireGuard?

No. Nebula predates the common WireGuard mesh tools and uses the Noise protocol framework with its own certificate format.

Apache Pulsar: Pulsar or Kafka?

Pulsar separates storage from compute and covers queuing and streaming in one system. Kafka has a far larger ecosystem and hiring pool. Most teams should have a specific reason before choosing Pulsar.

Nebula: Can I run it without Defined Networking?

Yes, entirely. Defined Networking sells the control plane conveniences, not the network itself.

Apache Pulsar: Why does separated storage matter?

Brokers hold no data, so adding or replacing one requires no rebalancing, and storage can grow without adding serving capacity.

Nebula: How do I revoke a host?

Add its certificate fingerprint to the blocklist in the configuration of the other hosts and reload them. There is no online revocation check.

Nebula: Is it a good fit for laptops?

Less so than the identity provider based tools. There is no single sign on, so every laptop needs a certificate issued and renewed by whatever process you build.

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