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Databases · head to head

EMQX vs LaunchDarkly

EMQX logo

EMQX

Databases

Erlang MQTT broker for large IoT fleets, relicensed to BSL with production free use limited to one node

From
Free
Free plan
Yes
Visit EMQXFull review
LaunchDarkly logo

LaunchDarkly

Developer Tools

Ship fast. Rest easy.

From
Free
Free plan
Yes
Visit LaunchDarklyFull review

The short version

  • LaunchDarkly is a feature management platform.
  • Free plans on both; paid from $234/mo and $12/mo.
  • Only EMQX lists erlang clustering; only LaunchDarkly lists feature flags.
  • Where LaunchDarkly falls short: pricing scales rapidly with monthly active users, becoming expensive at scale.
  • Prices and features on this page were last checked on 13 November 2026.

Where they differ

Only the attributes on which EMQX and LaunchDarkly actually diverge.

Attributes where EMQX and LaunchDarkly differ
AttributeEMQXLaunchDarkly
PlatformsLinux, Self-hosted, Web, macOSWeb, APIs
CategoryDatabasesDeveloper Tools

Identical on both: starting price (Free), free tier (Yes).

Not yet recorded: pricing model for LaunchDarkly, founded for EMQX.

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 LaunchDarkly

  • Feature flags
  • Progressive rollouts
  • User targeting
  • A/B testing
  • Kill switches
  • Audit log
  • Multi-environment
  • SDKs for all platforms

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

LaunchDarkly

  • Progressive deliverynot EMQX
  • Feature experimentationnot EMQX
  • Risk mitigationnot EMQX
  • Performance optimizationnot EMQX
  • Infrastructure migrationnot 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

LaunchDarkly

  • Pricing scales rapidly with monthly active users, becoming expensive at scale
  • Limited seats for engineers on standard plans, forcing upgrade to enterprise
  • Advanced features like experimentation and audit logs require higher-tier plans
  • Occasional reliability issues and backend delays reported by users

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/mo
    • Single tenant cluster
    • Traffic allowance included
    • 24/7 support
  • Enterprise self-managedOn request
    • Deploy on premises, at the edge or in any cloud
    • Clustering licensed
    • 256 MB maximum message size

LaunchDarkly

Free
  • DeveloperFree
    • Unlimited seats
    • Unlimited feature flags
    • A/B tests and experiments
  • FoundationOn request
    • $12 per connection
    • $10 per 1K MAU
    • Targeted segmentation
  • EnterpriseOn request
    • Custom pricing
    • Advanced automation
    • Compliance features

Which should you pick?

Choose EMQX if

  • You need erlang clustering.
  • You want to start without paying.
  • You work on Linux, Self-hosted, Web, macOS.
  • You also want mqtt 5.0 and quic.
EMQX review

Choose LaunchDarkly if

  • You need feature flags.
  • You want to start without paying.
  • You work on Web, APIs.
  • You also want progressive rollouts.
LaunchDarkly review

Questions people ask

Is EMQX or LaunchDarkly better?
Neither clearly leads. EMQX starts at Free and LaunchDarkly at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, EMQX or LaunchDarkly?
EMQX starts at Free and LaunchDarkly at Free.
Does EMQX or LaunchDarkly run on more platforms?
EMQX runs on Linux, Self-hosted, Web, macOS. LaunchDarkly runs on Web, APIs.
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 LaunchDarkly is typically brought in for.
What can EMQX do that LaunchDarkly cannot?
EMQX covers Erlang clustering, MQTT 5.0 and QUIC, Rule engine, Data integration sinks. LaunchDarkly covers Feature flags, Progressive rollouts, User targeting, A/B testing.

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.

LaunchDarkly: What does the free Developer plan include?

The free Developer plan includes unlimited seats, unlimited feature flags, A/B tests and experiments, 30 SDKs, 10 million logs and traces, 5,000 session replays and errors, and 14 days of data retention.

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.

LaunchDarkly: How does LaunchDarkly pricing scale?

Foundation plan pricing is $12 per connection plus $10 per 1,000 Monthly Active Users (MAU). Enterprise and Guardian plans have custom pricing based on usage, advanced features, and compliance requirements.

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.

LaunchDarkly: Does LaunchDarkly integrate with Jira and Slack?

Yes, LaunchDarkly integrates with Jira Cloud, allowing you to link feature flags to Jira issues and create issues from observability data. It also integrates with Slack for flag notifications and allows authorized members to trigger flag changes from Slack.

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.

LaunchDarkly: What is dark launching and how does LaunchDarkly enable it?

Dark launching keeps code changes hidden in production until ready to enable. LaunchDarkly enables this through feature flags that let teams safely test code in production before rolling out to users.

Source
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