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Databases · head to head

Couchbase vs EMQX

Couchbase logo

Couchbase

Databases

The modern database for enterprise 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: Couchbase the free tier is a single node with 8 GB of storage and forum support only; 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: Couchbase covers JSON Document Model, EMQX covers Erlang clustering.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Couchbase and EMQX actually diverge.

Attributes where Couchbase and EMQX differ
AttributeCouchbaseEMQX
Pricing modelfreemiumPer month by connection and session volume
PlatformsLinux, Windows, Mac, Docker, WebLinux, Docker, Kubernetes, Cloud, macOS
Founded2011Unknown

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 Couchbase

  • JSON Document Model
  • SQL++ Query
  • Full-text Search
  • Eventing
  • Analytics
  • Mobile Sync
  • Multi-dimensional Scaling
  • Kafka

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.

Couchbase

  • Running a distributed NoSQL document database as a managed servicenot EMQX
  • Mobile sync and offline first applications backed by a cloud databasenot EMQX

EMQX

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

Where each one falls short

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

Couchbase

  • The free tier is a single node with 8 GB of storage and forum support only
  • Node rates are hourly and quoted as starting figures, from $0.15 an hour on Basic to $0.49 on Enterprise
  • The Developer Pro and Enterprise plans require 3 nodes, so the hourly rate multiplies before any usage
  • Backup storage is billed separately at $0.07 per GB a month, and analytics backups at $0.14
  • Support response time is a plan feature, at 8 hours on Developer Pro against 30 minutes on Enterprise
  • AI and analytics run as separately priced planes at up to $0.86 an hour per node

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

Couchbase

Free
  • CommunityFree
    • Full features
    • Community support
    • Self-managed
  • Capella FreeFree
    • Managed service
    • Limited resources
    • Cloud hosted

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 Couchbase if

  • You need json document model.
  • You want to start without paying.
  • You work on Linux, Windows, Mac, Docker, Web.
  • You also want sql++ query.
Couchbase 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 Couchbase or EMQX better?
Neither clearly leads. Couchbase 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, Couchbase or EMQX?
Couchbase starts at Free and EMQX at Free.
Does Couchbase or EMQX run on more platforms?
Couchbase runs on Linux, Windows, Mac, Docker, Web. EMQX runs on Linux, Docker, Kubernetes, Cloud, macOS.
Can I use Couchbase for free?
Both have a free tier, so you can try either at no cost before committing.
What is Couchbase best used for?
Couchbase is most often used for running a distributed nosql document database as a managed service, mobile sync and offline first applications backed by a cloud database. Of those, running a distributed nosql document database as a managed service and mobile sync and offline first applications backed by a cloud database are not what EMQX is typically brought in for.
What can Couchbase do that EMQX cannot?
Couchbase covers JSON Document Model, SQL++ Query, Full-text Search, Eventing. EMQX covers Erlang clustering, MQTT 5.0 and QUIC, Rule engine, Data integration sinks.

Answered from the vendors’ own pages

Couchbase: Does Couchbase offer a free tier?

Yes, Couchbase offers a free tier option. Users can start for free from the main website.

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.

Couchbase: How do I access Couchbase pricing details?

Couchbase maintains a dedicated pricing page, but detailed tier information and costs are not available on the homepage. You can visit the pricing page or contact their sales team.

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.

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.

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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