MQTT

Publish telemetry from any endpoint to any standard MQTT broker — self-hosted or cloud. MQTT publishing is available in the Community Edition with no licence required.

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How It Works

Agent endpoints (Modbus, OPC-UA, BACnet, …)
         │
         ▼
   Subscription (agent)
         │  routes endpoint data to destination
         ▼
  MQTT Destination (agent)
         │  TCP / TLS
         │  username + password auth
         ▼
  MQTT Broker (any standard broker)
         │
         ▼
  Your cloud app / time-series DB / dashboard

The agent maintains a persistent MQTT connection to the broker and publishes batched telemetry as each subscription fires. If the connection drops, outgoing messages buffer to SQLite and flush automatically on reconnect.

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Setting Up an MQTT Destination

1. In the agent admin UI, go to Destinations → New Destination.
2. Select type MQTT.
3. Fill in the connection fields:

Field	Description
Host	Broker hostname or IP address (e.g. broker.hivemq.com, 192.168.1.100)
Port	TCP port — 1883 for plain MQTT, 8883 for MQTT over TLS
Username	Broker username (leave blank if the broker allows anonymous connections)
Password	Broker password
Client ID	MQTT client identifier — leave blank to auto-generate a unique ID
Topic prefix	Prepended to every published topic, e.g. edge/site-a → topics publish as edge/site-a/temperature

4. Click Save, then enable the destination toggle.

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Subscribing Endpoint Data

1. Go to Subscriptions → New Subscription.
2. Select the MQTT destination.
3. Choose the endpoints and data points to route.
4. Set the payload format:

Format	Best for
Tags	Generic MQTT consumers — flat JSON with field names and Unix-ms timestamp
ECP	Time-series databases — typed values, omits null/BAD quality readings
Custom	Iotistica consumers — full envelope with quality codes and deduplication ID

5. Click Save and enable the subscription.

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Cloud Provider Examples

HiveMQ Cloud

HiveMQ Cloud offers a free serverless MQTT broker with TLS and username/password auth.

1. Sign up at hivemq.com and create a free cluster.
2. In the HiveMQ console, go to Access Management → Credentials and create a username and password.
3. Note your cluster URL — e.g. abc123.s1.eu.hivemq.cloud.
4. In the agent, add an MQTT destination:

Field	Value
Host	<your-cluster>.s1.eu.hivemq.cloud
Port	8883
Username	HiveMQ credential username
Password	HiveMQ credential password
Topic prefix	e.g. iotistica/<site-name>

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EMQX Cloud

EMQX Cloud is a fully managed MQTT service with a free trial tier.

1. Create a deployment in the EMQX Cloud console.
2. Under Authentication, add a username and password.
3. Copy the Connection Address and port (1883 for standard, 8883 for TLS).
4. In the agent:

Field	Value
Host	Your EMQX deployment address
Port	8883 (recommended)
Username	EMQX auth username
Password	EMQX auth password
Topic prefix	e.g. plant/line-1

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Mosquitto (Self-Hosted)

Eclipse Mosquitto is the most widely deployed open-source MQTT broker and the same broker bundled with the Iotistica agent.

1. Install Mosquitto on any Linux host:

   sudo apt install mosquitto mosquitto-clients

2. Configure a password file:

   sudo mosquitto_passwd -c /etc/mosquitto/passwd myuser

3. Edit /etc/mosquitto/mosquitto.conf:

   listener 1883
   allow_anonymous false
   password_file /etc/mosquitto/passwd

4. In the agent:

Field	Value
Host	IP address of your Mosquitto host
Port	1883 (or 8883 with TLS configured)
Username	The username from the password file
Password	The password you set

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AWS IoT Core (MQTT)

AWS IoT Core supports standard MQTT with username/password via custom authorizers, or with X.509 certificates. For certificate-based auth with automatic credential rotation, use the dedicated AWS IoT Core integration (Agent Pro).

For simple username/password via a custom authorizer:

Field	Value
Host	<account-prefix>.iot.<region>.amazonaws.com
Port	443 or 8883
Username	Authorizer token (format per your authorizer config)
Password	Token signature

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The Things Network (TTN)

The Things Network exposes received LoRaWAN device data over MQTT.

Field	Value
Host	<region>.cloud.thethings.network
Port	8883
Username	<application-id>@<tenant-id>
Password	API key from the TTN console (Applications → API Keys)
Topic prefix	Leave blank — subscribe to TTN topics directly via an Endpoint

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Adafruit IO

Adafruit IO is a simple cloud dashboard with built-in MQTT support.

Field	Value
Host	io.adafruit.com
Port	1883 or 8883
Username	Your Adafruit IO username
Password	Your Adafruit IO key (from Account → Keys)
Topic prefix	<username>/feeds

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Payload Example

Using the Tags format, a single subscription publish looks like:

{
  "ts": 1718000000000,
  "tags": [
    { "name": "temperature", "value": 23.4, "quality": "GOOD" },
    { "name": "pressure",    "value": 1.01, "quality": "GOOD" }
  ]
}

Published to: <topic-prefix>/<endpoint-name>

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Troubleshooting

Symptom	Likely cause
Destination shows connection error	Wrong host or port, or broker not reachable from the agent network
Connection refused	Broker not running, or firewall blocking the port
Authentication failed	Wrong username or password
Messages not appearing	Check the subscription is enabled; use mosquitto_sub or MQTT Explorer to verify the topic
TLS handshake error	Broker requires TLS on port 8883 — verify the broker's certificate is trusted

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Related Docs

• Destinations — creating and managing publish destinations
• Subscriptions — routing endpoint data to a destination
• Data Publishing — payload formats and compression options
• AWS IoT Core — certificate-based AWS integration (Agent Pro)
• Azure IoT Hub — SAS token Azure integration (Agent Pro)
• GCP IoT Core — JWT GCP integration (Agent Pro)