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Databases · head to head

EMQX vs ScyllaDB

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
ScyllaDB logo

ScyllaDB

Databases

The real-time big data database compatible with Cassandra

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.; ScyllaDB enterprise tier requires custom quote from sales
  • They diverge on capability: EMQX covers Erlang clustering, ScyllaDB covers Cassandra Compatible.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which EMQX and ScyllaDB actually diverge.

Attributes where EMQX and ScyllaDB differ
AttributeEMQXScyllaDB
Pricing modelPer month by connection and session volumeusage-based
PlatformsLinux, Docker, Kubernetes, Cloud, macOSLinux, Docker, Kubernetes, Web
FoundedUnknown2015

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 ScyllaDB

  • Cassandra Compatible
  • DynamoDB Compatible
  • 10x Throughput
  • Low Latency
  • Auto-tuning
  • Lightweight Transactions
  • Change Data Capture
  • Cassandra Drivers

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

ScyllaDB

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

ScyllaDB

  • Enterprise tier requires custom quote from sales
  • Pricing varies by cloud provider, storage, and instance configuration
  • Contracts available but commitment required for subscription discounts

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

ScyllaDB

Free
  • ScyllaDB Cloud Standard$null/variable
    • Usage-based billing: vCPU, RAM, NVMe SSD storage
    • 2-hour P1 support response time
    • 99.9% uptime SLA
  • ScyllaDB Cloud Professional$null/variable
    • Enterprise-grade scalability
    • 1-hour P1 support response
    • Enhanced features included
  • ScyllaDB Cloud Premium$null/variable
    • Custom security and networking
    • 15-minute P1 support response
    • 99.99% uptime SLA
  • ScyllaDB Enterprise$null/quote
    • Self-managed deployment
    • On-premise or private cloud
    • Custom quote required

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 ScyllaDB if

  • You need cassandra compatible.
  • You want to start without paying.
  • You work on Linux, Docker, Kubernetes, Web.
  • You also want dynamodb compatible.
ScyllaDB review

Questions people ask

Is EMQX or ScyllaDB better?
Neither clearly leads. EMQX starts at Free and ScyllaDB at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, EMQX or ScyllaDB?
EMQX starts at Free and ScyllaDB at Free.
Does EMQX or ScyllaDB run on more platforms?
EMQX runs on Linux, Docker, Kubernetes, Cloud, macOS. ScyllaDB runs on Linux, Docker, Kubernetes, 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 ScyllaDB is typically brought in for.
What can EMQX do that ScyllaDB cannot?
EMQX covers Erlang clustering, MQTT 5.0 and QUIC, Rule engine, Data integration sinks. ScyllaDB covers Cassandra Compatible, DynamoDB Compatible, 10x Throughput, Low Latency.

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.

ScyllaDB: How is ScyllaDB Cloud pricing calculated?

ScyllaDB Cloud uses transparent, resource-based billing based on instance type (vCPU and RAM), NVMe SSD storage, service plan tier, deployment model, and cloud provider costs.

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.

ScyllaDB: Does ScyllaDB offer a free trial?

ScyllaDB offers a 30-day developer trial on smaller instances and a 48-hour production evaluation trial with full-grade instances.

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.

ScyllaDB: What cost savings are available for long-term ScyllaDB commitments?

ScyllaDB subscription contracts provide up to 70% or more in savings compared to on-demand hourly billing. 1-year and 3-year contract options are available.

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.

ScyllaDB: How much cheaper is ScyllaDB than DynamoDB?

Unlike DynamoDB which charges per read/write unit, ScyllaDB charges based on resource usage only, potentially delivering 50% or greater cost reduction for high-throughput workloads.

Source
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