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Databases · head to head

EMQX vs RavenDB

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
RavenDB logo

RavenDB

Databases

The fully transactional NoSQL document 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.; RavenDB the free Developer licence bars commercial use and expires every 6 months, requiring renewal
  • They diverge on capability: EMQX covers Erlang clustering, RavenDB covers ACID Transactions.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which EMQX and RavenDB actually diverge.

Attributes where EMQX and RavenDB differ
AttributeEMQXRavenDB
Pricing modelPer month by connection and session volumefreemium
PlatformsLinux, Docker, Kubernetes, Cloud, macOSLinux, Windows, Mac, Docker, Web
FoundedUnknown2010

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 RavenDB

  • ACID Transactions
  • Auto-indexing
  • Full-text Search
  • Graph Queries
  • Distributed Counters
  • Time Series
  • Document Compression
  • .NET

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

RavenDB

  • Running a distributed document database with ACID transactionsnot EMQX
  • Self hosting a multi node database cluster on your own hardwarenot EMQX
  • Replicating operational data out to analytics systems through ETLnot 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.

RavenDB

  • The free Developer licence bars commercial use and expires every 6 months, requiring renewal
  • The free Community licence caps a customer at 60 cores and forces you to stay on the latest major version
  • The Professional licence is limited to a single database, a 5 node cluster, 40 cores and 240 GB RAM
  • Sharding across nodes, ETL to OLAP, Elasticsearch and Kafka, and data archival are Enterprise only
  • Enterprise and AI licence pricing is contact us only with no published rate

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

RavenDB

Free
  • CommunityFree
    • 3 cores
    • 6GB RAM
    • Community support
  • Professional$499/year
    • Production use
    • Professional support
    • Advanced features

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 RavenDB if

  • You need acid transactions.
  • You want to start without paying.
  • You work on Linux, Windows, Mac, Docker, Web.
  • You also want auto-indexing.
RavenDB review

Questions people ask

Is EMQX or RavenDB better?
Neither clearly leads. EMQX starts at Free and RavenDB at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, EMQX or RavenDB?
EMQX starts at Free and RavenDB at Free.
Does EMQX or RavenDB run on more platforms?
EMQX runs on Linux, Docker, Kubernetes, Cloud, macOS. RavenDB 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 RavenDB is typically brought in for.
What can EMQX do that RavenDB cannot?
EMQX covers Erlang clustering, MQTT 5.0 and QUIC, Rule engine, Data integration sinks. RavenDB covers ACID Transactions, Auto-indexing, Full-text Search, Graph Queries.

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.

RavenDB: Is RavenDB free or open source?

RavenDB is open source under the AGPLv3 license and available on GitHub. It also offers a free developer license with enterprise-level features limited to 9 cores, 36GB max RAM, 3 nodes, and non-commercial use.

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.

RavenDB: Can I use RavenDB commercially for free?

RavenDB offers a free Community License that permits commercial deployment with unlimited databases and sizes, subject to a 60-core maximum per customer and requirement to run the latest major version.

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.

RavenDB: What commercial licensing options does RavenDB offer?

RavenDB offers Professional, Enterprise, and AI tiers for commercial use. Pricing for these tiers requires contacting their sales team at [email protected].

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.

RavenDB: Does RavenDB offer a cloud hosting option?

RavenDB Cloud provides a fully managed cloud database with maintenance, failover, and backups included. Pricing is available at cloud.ravendb.net/pricing.

Source
RavenDB: Is there a refund window if I purchase RavenDB?

RavenDB offers a 30-day refund window for purchased licenses.

Source
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