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Databases · head to head

DataStax vs EMQX

DataStax logo

DataStax

Databases

The real-time data company for AI applications

From
Free
Rated
-
Full reviewWebsite
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

The short version

  • Each has a real cost: DataStax dataStax's own Astra DB documentation states the Enterprise plan is an annual, contract-based plan with negotiated pricing, meaning list prices are not published for that tier; 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.
  • They diverge on capability: DataStax covers Cassandra Compatible, EMQX covers Erlang clustering.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which DataStax and EMQX actually diverge.

Attributes where DataStax and EMQX differ
AttributeDataStaxEMQX
Pricing modelfreemiumPer month by connection and session volume
PlatformsWeb, Aws, Azure, GcpLinux, Docker, Kubernetes, Cloud, macOS
Founded2010Unknown

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 DataStax

  • Cassandra Compatible
  • Vector Search
  • Serverless
  • Multi-cloud
  • Streaming
  • CDC
  • GraphQL API
  • LangChain

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

What people use each for

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

DataStax

  • Real-time applicationsnot EMQX
  • Content managementnot EMQX
  • User profilesnot EMQX
  • Mobile backendsnot EMQX
  • Cachingnot EMQX

EMQX

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

Where each one falls short

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

DataStax

  • DataStax's own Astra DB documentation states the Enterprise plan is an annual, contract-based plan with negotiated pricing, meaning list prices are not published for that tier
  • DataStax's Astra DB documentation directs Standard plan customers to IBM's watsonx.data pricing for exact consumption-based rates following the DataStax/IBM deal, rather than publishing them on DataStax's own site

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.

Pricing, plan by plan

DataStax

Free
  • FreeFree
    • 5GB storage
    • 40M read/write ops
    • Vector search
  • Pay As You GoFree
    • Usage-based pricing
    • Multi-region
    • Enterprise support

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

Which should you pick?

Choose DataStax if

  • You need cassandra compatible.
  • You want to start without paying.
  • You work on Web, Aws, Azure, Gcp.
  • You also want vector search.
DataStax review

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

Questions people ask

Is DataStax or EMQX better?
Neither clearly leads. DataStax starts at Free and EMQX at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, DataStax or EMQX?
DataStax starts at Free and EMQX at Free.
Does DataStax or EMQX run on more platforms?
DataStax runs on Web, Aws, Azure, Gcp. EMQX runs on Linux, Docker, Kubernetes, Cloud, macOS.
Can I use DataStax for free?
Both have a free tier, so you can try either at no cost before committing.
What is DataStax best used for?
DataStax is most often used for real-time applications, content management, user profiles, mobile backends. Of those, real-time applications and content management are not what EMQX is typically brought in for.
What can DataStax do that EMQX cannot?
DataStax covers Cassandra Compatible, Vector Search, Serverless, Multi-cloud. EMQX covers Erlang clustering, MQTT 5.0 and QUIC, Rule engine, Data integration sinks.

Answered from the vendors’ own pages

DataStax: Is DataStax available as a managed service?

Yes, DataStax is available as Astra DB, a managed database service. Users can sign up for Astra DB directly to create accounts and access the platform.

Source
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.

DataStax: How is DataStax priced?

DataStax (now part of IBM) does not publish pricing on its documentation homepage. Pricing information would need to be obtained through the Astra DB signup page or by contacting IBM directly.

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.

DataStax: Is there an enterprise licensing option?

DataStax is now part of IBM. Enterprise customers should contact IBM directly for licensing agreements and enterprise-specific pricing.

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.

DataStax: Can I try DataStax without an account?

To use DataStax Astra DB, account creation is required. The documentation does not mention a free trial or demonstration environment that does not require signup.

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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