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Developer Tools · head to head

CodeSandbox vs EMQX

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CodeSandbox

Developer Tools

Cloud platform for instant, isolated development sandboxes and code execution

From
Free
Free plan
Yes
Visit CodeSandboxFull review
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

The short version

  • CodeSandbox is free; EMQX starts at $234/mo.
  • Only CodeSandbox lists instant sandboxes; only EMQX lists erlang clustering.
  • Where CodeSandbox falls short: public sandboxes are visible to others by default, which is not ideal for proprietary code.
  • Prices and features on this page were last checked on 31 August 2026.

Where they differ

Only the attributes on which CodeSandbox and EMQX actually diverge.

Attributes where CodeSandbox and EMQX differ
AttributeCodeSandboxEMQX
Pricing modelFreemiumPer month by connection and session volume
PlatformsWeb, APILinux, Self-hosted, Web, macOS
CategoryDeveloper ToolsDatabases

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

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 CodeSandbox

  • Instant sandboxes
  • Programmatic sandbox API
  • Secure isolated execution
  • Browser-based editor
  • CI/CD sandbox support
  • Scalable VM infrastructure

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.

CodeSandbox

  • Running AI agent-generated code safely in isolationnot EMQX
  • Prototyping and sharing web projects in-browsernot EMQX
  • Executing untrusted code for a code playground productnot EMQX
  • Using sandboxes as ephemeral CI/CD build environmentsnot EMQX

EMQX

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

Where each one falls short

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

CodeSandbox

  • Focus has shifted toward programmatic sandbox infrastructure, which may be less approachable for casual users just wanting a quick online editor
  • Public sandboxes are visible to others by default, which is not ideal for proprietary code

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

CodeSandbox

Free
  • FreeFree
    • Public sandboxes
    • Basic sandbox usage

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

Which should you pick?

Choose CodeSandbox if

  • You need instant sandboxes.
  • You want to start without paying.
  • You work on Web, API.
  • You also want programmatic sandbox api.
CodeSandbox review

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

Questions people ask

Is CodeSandbox or EMQX better?
Neither clearly leads. CodeSandbox 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, CodeSandbox or EMQX?
CodeSandbox starts at Free and EMQX at Free.
Does CodeSandbox or EMQX run on more platforms?
CodeSandbox runs on Web, API. EMQX runs on Linux, Self-hosted, Web, macOS.
Can I use CodeSandbox for free?
Both have a free tier, so you can try either at no cost before committing.
What is CodeSandbox best used for?
CodeSandbox is most often used for running ai agent-generated code safely in isolation, prototyping and sharing web projects in-browser, executing untrusted code for a code playground product, using sandboxes as ephemeral ci/cd build environments. Of those, running ai agent-generated code safely in isolation and prototyping and sharing web projects in-browser are not what EMQX is typically brought in for.
What can CodeSandbox do that EMQX cannot?
CodeSandbox covers Instant sandboxes, Programmatic sandbox API, Secure isolated execution, Browser-based editor. EMQX covers Erlang clustering, MQTT 5.0 and QUIC, Rule engine, Data integration sinks.

Answered from the vendors’ own pages

CodeSandbox: Does CodeSandbox offer a free tier?

Yes, CodeSandbox offers a free option available on the platform. Users can start for free.

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.

CodeSandbox: Where can I find CodeSandbox's pricing details?

CodeSandbox maintains a dedicated pricing page, but specific tier names, feature breakdowns, and costs are not displayed on the landing page.

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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