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Databases · head to head

EMQX vs Zilliz

EMQX logo

EMQX

Databases

Erlang MQTT broker for large IoT fleets, relicensed to BSL with production free use limited to one node

From
Free
Rated
-
Full reviewWebsite
Zilliz logo

Zilliz

Databases

Managed vector database and vector lakebase for AI applications

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: EMQX the move to Business Source Licence 1.1 at version 5.9 in May 2025 limits free production use to a single node, so the clustering that justifies choosing EMQX now requires a paid subscription from the second node onward.; Zilliz pricing structure not publicly disclosed, requires sales contact
  • They diverge on capability: EMQX covers Erlang clustering, Zilliz covers Vector indexing.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which EMQX and Zilliz actually diverge.

Attributes where EMQX and Zilliz differ
AttributeEMQXZilliz
Pricing modelPer month by connection and session volumecontact-sales
PlatformsLinux, Docker, Kubernetes, Cloud, macOSCloud, Self-hosted
FoundedUnknown2017

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Databases).

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 EMQX

  • Erlang clustering
  • MQTT 5.0 and QUIC
  • Rule engine
  • Data integration sinks
  • Session persistence
  • Multi protocol gateways
  • Authentication and authorisation
  • Dashboard and REST API

Only in Zilliz

  • Vector indexing
  • Distributed architecture
  • SQL interface
  • Tensor support
  • Real-time search
  • Cloud-native
  • Open-source compatible

What people use each for

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

EMQX

  • A connected vehicle platform needing millions of persistent MQTT sessions with QUIC for handover across mobile networksnot Zilliz
  • An industrial operator routing sensor telemetry straight into TimescaleDB or Kafka without writing a consumer servicenot Zilliz
  • An IoT product team that has outgrown a single Mosquitto instance and needs clustering and shared subscriptionsnot Zilliz
  • A smart building deployment mixing MQTT, CoAP and LwM2M devices on one brokernot Zilliz

Zilliz

  • Build retrieval-augmented generation (RAG) systemsnot EMQX
  • Implement semantic search over documentsnot EMQX
  • Create multimodal search with text and imagesnot EMQX
  • Power recommendation engines with vector similaritynot EMQX
  • Enable similarity search on user embeddingsnot EMQX

Where each one falls short

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

EMQX

  • The move to Business Source Licence 1.1 at version 5.9 in May 2025 limits free production use to a single node, so the clustering that justifies choosing EMQX now requires a paid subscription from the second node onward.
  • The relicensing arrived in a minor release, which caught users who had pinned to 5.x expecting Apache 2.0 terms and forced legal review of existing deployments.
  • Running an Erlang/OTP cluster well requires operational knowledge most teams do not have, and diagnosing distribution, mnesia or memory issues means learning a runtime you use for nothing else.
  • Enterprise pricing is quoted rather than published for the self-managed edition, so the cost of the clustered configuration you actually need is invisible until you talk to sales.
  • The Serverless tier caps at around a thousand connections and shares infrastructure, which makes it a prototyping tier rather than a genuine small production option.

Zilliz

  • Pricing structure not publicly disclosed, requires sales contact
  • Operational complexity for self-hosted Milvus deployments
  • Learning curve for those unfamiliar with vector databases
  • Limited built-in analytics compared to some alternatives

Pricing, plan by plan

EMQX

Free
  • Open Source single nodeFree
    • BSL 1.1 licence since version 5.9
    • Free production use of one node only
    • All former enterprise features visible
  • ServerlessFree
    • Free monthly quota then pay as you go
    • Up to 1,000 connections
    • 8 by 5 support
  • Dedicated Flex$234/month
    • Single tenant cluster
    • Traffic allowance included
    • 24/7 support
  • Enterprise self-managed$undefined/year
    • Deploy on premises, at the edge or in any cloud
    • Clustering licensed
    • 256 MB maximum message size

Zilliz

Free

No published plan breakdown. See the Zilliz review.

Which should you pick?

Choose EMQX if

  • You need erlang clustering.
  • You want to start without paying.
  • You work on Linux, Docker, Kubernetes, Cloud, macOS.
  • You also want mqtt 5.0 and quic.
EMQX review

Choose Zilliz if

  • You need vector indexing.
  • You want to start without paying.
  • You work on Cloud, Self-hosted.
  • You also want distributed architecture.
Zilliz review

Questions people ask

Is EMQX or Zilliz better?
Neither clearly leads. EMQX starts at Free and Zilliz at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, EMQX or Zilliz?
EMQX starts at Free and Zilliz at Free.
Does EMQX or Zilliz run on more platforms?
EMQX runs on Linux, Docker, Kubernetes, Cloud, macOS. Zilliz runs on Cloud, Self-hosted.
Can I use EMQX for free?
Both have a free tier, so you can try either at no cost before committing.
What is EMQX best used for?
EMQX is most often used for a connected vehicle platform needing millions of persistent mqtt sessions with quic for handover across mobile networks, an industrial operator routing sensor telemetry straight into timescaledb or kafka without writing a consumer service, an iot product team that has outgrown a single mosquitto instance and needs clustering and shared subscriptions, a smart building deployment mixing mqtt, coap and lwm2m devices on one broker. Of those, a connected vehicle platform needing millions of persistent mqtt sessions with quic for handover across mobile networks and an industrial operator routing sensor telemetry straight into timescaledb or kafka without writing a consumer service are not what Zilliz is typically brought in for.
What can EMQX do that Zilliz cannot?
EMQX covers Erlang clustering, MQTT 5.0 and QUIC, Rule engine, Data integration sinks. Zilliz covers Vector indexing, Distributed architecture, SQL interface, Tensor support.

Answered from the vendors’ own pages

EMQX: Is EMQX still open source?

Not in the OSI sense since version 5.9. It is source-available under Business Source Licence 1.1, reverting to Apache 2.0 four years after each release.

Zilliz: What is the difference between Milvus and Zilliz Cloud?

Milvus is the open-source vector database that you can self-host. Zilliz Cloud is the fully managed service built on Milvus that removes operational overhead and handles scaling automatically.

Source
EMQX: Can I run a free cluster?

No. The additional use grant permits free production use of one node; clustering requires a commercial licence.

Zilliz: How many vectors can Zilliz handle?

Milvus and Zilliz Cloud can store and search billions of vectors through their distributed architecture that separates storage and compute layers.

Source
EMQX: What changed for existing users?

Community and enterprise editions merged, so all features are now visible, but the licence terms tightened in the same minor release.

Zilliz: Is Milvus open-source?

Yes, Milvus is open-source under the Apache License 2.0 and is part of the LF AI & Data Foundation.

Source
EMQX: Which version is still Apache 2.0?

Releases before 5.9 remain under Apache 2.0, and each BSL release converts to Apache 2.0 four years after publication.

Zilliz: What pricing does Zilliz Cloud offer?

Zilliz Cloud pricing is not publicly listed and requires contacting their team to discuss your specific scale and use case requirements.

Source
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