Eclipse Mosquittovs
RabbitMQ
RabbitMQ: RabbitMQ when you need clustering, persistent queues across nodes and commercial support.
Eclipse Mosquitto
Small, EPL-licensed MQTT broker that runs on hardware other brokers cannot
As of 31 August 2026, Eclipse Mosquitto is free to use. The default MQTT broker of the hobbyist and edge world, small enough to run on a router or a Raspberry Pi. Softwr lists it under Networking. Eclipse Mosquitto is made by Eclipse Foundation, available on Linux, Windows, macOS, Docker.
Overview
What Eclipse Mosquitto does
Mosquitto is an Eclipse Foundation project implementing MQTT 5.0, 3.1.1 and 3.1 in C. It ships in every major Linux distribution, runs in a few megabytes of memory, and includes the mosquitto_pub and mosquitto_sub command line clients that have become the standard way to poke at any MQTT deployment. Authentication, access control lists, TLS, WebSockets and bridging to another broker are all built in and configured in a single text file. The distinguishing property is size. Mosquitto will run on an OpenWrt router, an industrial gateway or a Pi Zero, which is why it dominates the edge and why most home automation stacks, including Home Assistant, assume it. A broker that needs a JVM and a gigabyte of heap simply cannot go where Mosquitto goes. The limit is equally clear: Mosquitto is a single process with no clustering. Persistence is a local file, and high availability means running two brokers with an external failover arrangement you build yourself. It scales to a few thousand concurrent clients on ordinary hardware, well past most edge use cases and well short of a national device fleet. The licence is the Eclipse Public License 2.0 with an Eclipse Distribution Licence, a weak copyleft that is fine for deployment but that some organisations treat differently from Apache 2.0 when embedding it in a shipped product.
What people use it for
- A home or building automation stack where the broker must run on the same small computer as everything else
- An industrial gateway that buffers local telemetry and bridges selected topics to a cloud broker
- Local development and testing of MQTT clients without provisioning a cloud IoT service
- An air-gapped deployment where a broker with no licence server and no phone-home behaviour is a requirement
Related searches
The honest half
Where it falls short
Concrete and checkable, so you can decide whether any of them matter to you. This is the half of a review a vendor will not write about Eclipse Mosquitto.
- There is no clustering: Mosquitto is a single process, so high availability means building your own failover and accepting session loss on switchover.
- Persistence is a local file rather than a replicated store, so a disk failure or an unclean shutdown can lose retained messages and queued QoS traffic.
- Practical capacity is a few thousand concurrent clients on typical hardware, so a growing device fleet eventually forces a migration to a clustered broker.
- The Eclipse Public Licence is weak copyleft rather than permissive, which some legal teams treat as a blocker when embedding the broker in a shipped commercial product.
- There is no commercial support to buy from the project, so production incidents rely on community mailing lists or on paying a third party who happens to know the codebase.
Cross-shopped
What people choose instead of Eclipse Mosquitto
Each pairing was judged by two reviewers asking whether a buyer would genuinely weigh the two against each other. The ones that failed were deleted rather than published.
- Eclipse MosquittovsMQTT
MQTT: MQTT as the protocol if you are still deciding on a standard rather than an implementation.
- Eclipse MosquittovsNATS
NATS: NATS if you want a small, fast broker but are not tied to the MQTT protocol.
Pricing
What Eclipse Mosquitto costs
Taken from the vendor's own pricing page. Prices move, so check before you buy.
Eclipse Mosquitto
Free
- Eclipse Public License 2.0 with Eclipse Distribution Licence
- MQTT 5.0, 3.1.1 and 3.1
- No client or message limits beyond your hardware
- Community support only
- No commercial support offering from the project
Capabilities
Features
MQTT 5.0 support
Full protocol support including shared subscriptions and topic aliases
Very small footprint
Runs in a few megabytes on routers, gateways and single-board computers
Bridging
Forward selected topics to another broker, including cloud brokers, over TLS
WebSockets listener
Browser clients connect directly without a separate gateway
Command line clients
mosquitto_pub and mosquitto_sub, the de facto MQTT debugging tools
Dynamic security plugin
Runtime-configurable clients, groups and access control roles
Answered, with sources
Questions people ask
Each answer names the page it came from, so you can check it rather than take our word for it.
Can Mosquitto be clustered?
No. It is a single process. High availability requires an external failover arrangement you build yourself.
What licence is it?
Eclipse Public License 2.0 alongside the Eclipse Distribution License, a weak copyleft rather than a permissive licence.
How many clients can it handle?
A few thousand concurrent connections on ordinary hardware; beyond that, use a clustered broker.
Does it support MQTT 5?
Yes, along with 3.1.1 and 3.1.
Keep looking
Where to go from Eclipse Mosquitto
- Eclipse Mosquitto alternativesEvery product people weigh against it
- Eclipse Mosquitto pricingPlans, floors and what the tiers exclude
- Eclipse Mosquitto badgesWhich rules it meets, and the figure behind each
- All Networking softwareThe full category
- Best Networking softwareThe shortlist, and how it was cut
Best Networking software for
Compare Eclipse Mosquitto with
- HiveMQ
- Traefik
- pfSense
- OpenVPN
- Icinga
- Consul
- LibreNMS
- Zabbix
- Nebula
- MikroTik RouterOS
- PRTG Network Monitor
- Netdata
- Catchpoint
- Ubiquiti UniFi
- OpenVPN
- Icinga
- LibreNMS
- MikroTik RouterOS
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12 researched notes
Softwr does not host reviews and shows no star rating for Eclipse Mosquitto, because a rating we did not collect is not ours to publish. What is here is the pricing and platform detail from the vendor’s own pages, limitations we could state concretely, and alternatives a reviewer confirmed people weigh against it. Tell us if any of it is wrong.
More on Eclipse Mosquitto
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Every tier, and where the cost actually lands
Compare Eclipse Mosquitto
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