Softwr

Databases · head to head

EMQX vs Neo4j

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
Neo4j logo

Neo4j

Databases

The world's leading graph database

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.; Neo4j auraDB Free has no service availability SLA, no backups and no point-in-time recovery
  • They diverge on capability: EMQX covers Erlang clustering, Neo4j covers Native Graph Storage.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which EMQX and Neo4j actually diverge.

Attributes where EMQX and Neo4j differ
AttributeEMQXNeo4j
Pricing modelPer month by connection and session volumefreemium
PlatformsLinux, Docker, Kubernetes, Cloud, macOSLinux, Windows, Mac, Docker, Web
FoundedUnknown2007

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 Neo4j

  • Native Graph Storage
  • Cypher Query Language
  • ACID Transactions
  • High Availability
  • Graph Data Science
  • Full-text Search
  • Native Indexes
  • GraphQL

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 Neo4j
  • An industrial operator routing sensor telemetry straight into TimescaleDB or Kafka without writing a consumer servicenot Neo4j
  • An IoT product team that has outgrown a single Mosquitto instance and needs clustering and shared subscriptionsnot Neo4j
  • A smart building deployment mixing MQTT, CoAP and LwM2M devices on one brokernot Neo4j

Neo4j

  • Graph database for learning and explorationnot EMQX
  • Production workloads requiring high availability and multi-zone redundancynot EMQX
  • Enterprise deployments needing custom infrastructurenot 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.

Neo4j

  • AuraDB Free has no service availability SLA, no backups and no point-in-time recovery
  • AuraDB Free imposes limits on node and relationship counts and runs single-zone only
  • SSO authentication and role-based access control are excluded from AuraDB Free and AuraDB Professional, starting only at Business Critical at $146 per GB per month with a 2GB minimum cluster
  • AuraDB Professional starts at $65 per GB per month with a minimum 1GB cluster and caps at 128GB memory per instance
  • AuraDB Professional backups are daily with only 7-day retention, against 30 days on Business Critical
  • Customer managed keys and private endpoints are available only on AuraDB Virtual Dedicated Cloud, which is quote only with no published price
  • Change data capture, query log forwarding, secondaries and access to Neo4j Professional Services are excluded below the Business Critical tier
  • Support on AuraDB Free is community only and AuraDB Professional is best effort, with 24x7 one-hour response starting at Business Critical
  • AuraDB Virtual Dedicated Cloud is sold on prepaid contract terms with enterprise commercial negotiation rather than self-serve card payment

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

Neo4j

Free
  • FreeFree
    • Learning and exploration access
    • No credit card required
    • All graph tools included
  • AuraDB Professional$65/GB/month
    • 1GB minimum cluster
    • Hourly billing available ($0.09/hour for 1GB)
    • Daily backups with 7-day retention
  • AuraDB Business Critical$146/GB/month
    • 2GB minimum cluster
    • Hourly billing available ($0.40/hour for 2GB)
    • Up to 512GB maximum
  • Virtual Dedicated Cloud$null/custom
    • Custom pricing via sales contact
    • Dedicated VPC infrastructure
    • Hourly backups with 60-day retention

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 Neo4j if

  • You need native graph storage.
  • You want to start without paying.
  • You work on Linux, Windows, Mac, Docker, Web.
  • You also want cypher query language.
Neo4j review

Questions people ask

Is EMQX or Neo4j better?
Neither clearly leads. EMQX starts at Free and Neo4j at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, EMQX or Neo4j?
EMQX starts at Free and Neo4j at Free.
Does EMQX or Neo4j run on more platforms?
EMQX runs on Linux, Docker, Kubernetes, Cloud, macOS. Neo4j runs on Linux, Windows, Mac, Docker, Web.
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 Neo4j is typically brought in for.
What can EMQX do that Neo4j cannot?
EMQX covers Erlang clustering, MQTT 5.0 and QUIC, Rule engine, Data integration sinks. Neo4j covers Native Graph Storage, Cypher Query Language, ACID Transactions, High Availability.

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.

Neo4j: Is Neo4j free?

Neo4j offers a free tier (AuraDB Free) for learning and exploration with no credit card required. Community Edition is also free and GPL3-licensed. Paid tiers start at $65/GB per month for AuraDB Professional.

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.

Neo4j: What does Neo4j's Professional tier include?

AuraDB Professional costs $65/GB per month with a 1GB minimum cluster, includes daily backups with 7-day retention, single-zone availability, and best-effort support. Hourly billing is available at $0.09/hour per GB.

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.

Neo4j: What is Neo4j's most advanced pricing tier?

AuraDB Business Critical costs $146/GB per month with a 2GB minimum and includes multi-zone redundancy, 99.95% uptime SLA, 24/7 premium support with one-hour response times, and point-in-time recovery.

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.

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