Complete MQTT 5.0
Every packet property, topic aliases, shared subscriptions via $share, subscription identifiers, No Local, Retain Handling, Will Delay, Message Expiry, reason codes, the AUTH packet.
Version 1.0.30 · free, no limits
An MQTT broker for everyone
ELX-MQTT Broker is a Go broker with a full web dashboard. MQTT 3.1.1 and 5.0 are implemented from scratch, completely, with no third-party libraries. One binary, no dependencies: install it and it runs.
Debian · Ubuntu · Windows x64 · Linux arm64 and armhf
$ sudo apt-get install elxmqttbroker Setting up elxmqttbroker (1.0.30) ... Created symlink /etc/systemd/system/multi-user.target.wants/elxmqttbroker.service ELX MQTT Broker 1.0.30 — listening on :1883, :8883, dashboard on :8567 state restored retained=128 sessions=7 subscriptions=34 delayed=2
2
protocol versions: 3.1.1 and 5.0
0
third-party MQTT libraries
7
dashboard languages
6
credential sources
Everything you expect from a broker — plus a dashboard to watch it
The broker does not just deliver messages, it shows exactly what is happening: who is connected, which topics are alive, what the limiters drop.
A live dashboard
Message-rate and traffic charts, machine health, active topics and an event feed — streamed over WebSocket, with no page reloads.
Topic-level permissions
ACL rules of filter + access + allow or deny, deny-by-default, and a $u placeholder that confines a client to its own branch in a single line.
Broker-to-broker bridging
Server-level two-way topic forwarding: out/in/both directions, prefixes, TLS, loop protection and automatic reconnect.
Delayed publish
Publishing to $delayed/60/topic reaches subscribers a minute later. EMQX-compatible, survives a restart, and the queue is visible and cancellable in the dashboard.
Flood control and topic limits
A per-connection token bucket plus per-topic-pattern rules: thin a stream down to a rate (keeping the latest value) or drop it entirely.
Six credential sources
The built-in list, MariaDB/MySQL, SQLite, CSV, JWT and an external HTTP service. Switching happens live, without restarting the broker.
REST API
Everything the dashboard does is available with a bearer token: provision devices and grant permissions from your own system. Read-only tokens are supported.
Survives restarts
Retained messages, persistent sessions, offline queues and delayed messages live in pure-Go SQLite — no CGO and no external database.
Installing takes a minute
An APT repository package for Debian and Ubuntu, a ready binary for Windows. No Docker, no runtime, no libraries to install.
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Add the key and the repository
sudo wget -qO /usr/share/keyrings/elx-repo.gpg https://repo.um-d.ru/elx-repo.gpg echo "deb [signed-by=/usr/share/keyrings/elx-repo.gpg] https://repo.um-d.ru stable main" | sudo tee /etc/apt/sources.list.d/elx-repo.list -
Refresh the package list
sudo apt-get update -
Install the broker
sudo apt-get install elxmqttbroker
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Download the installer from the download page
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Run it and pick “Install as a Windows service”
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Open the dashboard and sign in as admin / admin
http://localhost:8567
Once installed, the dashboard waits on :8567, MQTT on :1883 and MQTT over TLS on :8883. The default login is admin / admin — change it on first sign-in.
What it looks like
Dark and light themes, seven interface languages, live charts. The dashboard is part of the broker — there is nothing separate to install.
What is supported
The codec encodes and decodes all 15 packet types, and topics are matched against the table from the specification.
Shared by 3.1.1 and 5.0
- QoS 0, 1 and 2 with full handshakes
- Redelivery after reconnect
- Retained messages and branch clearing
- Last Will and Testament
- Clean and persistent sessions
- Keep-alive and session takeover
- The + and # wildcards
- A $SYS tree with statistics
MQTT 5.0 only
- Every packet property
- Topic aliases in both directions
- Session Expiry Interval
- Receive Maximum and flow control
- Subscription identifiers
- Shared subscriptions $share/group/filter
- No Local and Retain As Published
- Retain Handling 0/1/2
- Will Delay and Message Expiry
- Content Type, Response Topic, Correlation Data
- User Properties and reason codes
- Server-side DISCONNECT and the AUTH packet
Transports
- :1883 — MQTT over TCP
- :8883 — MQTT over TLS
- :8567/mqtt — MQTT over WebSocket
- :8567 — the web dashboard
- A TLS certificate is generated on first run
- Your own certificate goes in the config
Proven under load
Stress-tested on two benches — over the network and loopback. Just the highlights here; the full report with method and tables is one click away.
Install it and try
The broker is free, the number of devices and messages is unlimited, and no sign-up is required.