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Databases · head to head

EMQX vs YugabyteDB

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
YugabyteDB logo

YugabyteDB

Databases

Open source distributed SQL database for cloud native apps

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.; YugabyteDB missing PostgreSQL functions and extensions despite claiming compatibility
  • They diverge on capability: EMQX covers Erlang clustering, YugabyteDB covers PostgreSQL Compatible.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which EMQX and YugabyteDB actually diverge.

Attributes where EMQX and YugabyteDB differ
AttributeEMQXYugabyteDB
Pricing modelPer month by connection and session volumeUnknown
PlatformsLinux, Docker, Kubernetes, Cloud, macOSCloud, On-premises, Kubernetes
FoundedUnknown2016

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 YugabyteDB

  • PostgreSQL Compatible
  • Distributed SQL
  • Geo-distribution
  • Linear Scalability
  • High Availability
  • ACID Transactions
  • CDC Support
  • PostgreSQL

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 YugabyteDB
  • An industrial operator routing sensor telemetry straight into TimescaleDB or Kafka without writing a consumer servicenot YugabyteDB
  • An IoT product team that has outgrown a single Mosquitto instance and needs clustering and shared subscriptionsnot YugabyteDB
  • A smart building deployment mixing MQTT, CoAP and LwM2M devices on one brokernot YugabyteDB

YugabyteDB

  • Transaction processingnot EMQX
  • Data storagenot EMQX
  • Application backendnot EMQX
  • Reportingnot EMQX
  • Data analyticsnot 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.

YugabyteDB

  • Missing PostgreSQL functions and extensions despite claiming compatibility
  • Not a true PostgreSQL replacement requiring schema and query compatibility testing before migration
  • Requires careful isolation level management or risk data corruption in production
  • Lacks built-in OLAP capabilities, requiring external systems for analytics
  • Coupled compute and storage scaling reduces optimization flexibility

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

YugabyteDB

Free

No published plan breakdown. See the YugabyteDB 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 YugabyteDB if

  • You need postgresql compatible.
  • You want to start without paying.
  • You work on Cloud, On-premises, Kubernetes.
  • You also want distributed sql.
YugabyteDB review

Questions people ask

Is EMQX or YugabyteDB better?
Neither clearly leads. EMQX starts at Free and YugabyteDB at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, EMQX or YugabyteDB?
EMQX starts at Free and YugabyteDB at Free.
Does EMQX or YugabyteDB run on more platforms?
EMQX runs on Linux, Docker, Kubernetes, Cloud, macOS. YugabyteDB runs on Cloud, On-premises, Kubernetes.
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 YugabyteDB is typically brought in for.
What can EMQX do that YugabyteDB cannot?
EMQX covers Erlang clustering, MQTT 5.0 and QUIC, Rule engine, Data integration sinks. YugabyteDB covers PostgreSQL Compatible, Distributed SQL, Geo-distribution, Linear Scalability.

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.

YugabyteDB: Is YugabyteDB a true drop-in replacement for PostgreSQL?

No, YugabyteDB is PostgreSQL-compatible but not a zero-change drop-in replacement. It requires compatibility testing with queries, stored procedures, and ORM configurations before migration.

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.

YugabyteDB: What isolation levels does YugabyteDB support?

YugabyteDB allows per-query selection between serializable isolation for critical operations and read-committed for analytics. However, this flexibility requires careful management to avoid accidental data corruption.

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.

YugabyteDB: Does YugabyteDB support both SQL and NoSQL workloads?

Yes, YugabyteDB offers YSQL for PostgreSQL-compatible SQL and YCQL for Cassandra-like NoSQL workloads, using the same DocDB storage engine to support both simultaneously.

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.

YugabyteDB: Can YugabyteDB scale compute and storage independently?

No, YugabyteDB couples compute and storage scaling, unlike TiDB which separates them. This means scaling decisions are less flexible and optimization is more complex.

Source
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