MQTT Topics can have one or more levels and the levels are separated by forward slash. Topics are case-sensitive. Examples of MQTT topics are,<\/p>\n
- \n
- office\/groundfloor\/room1\/temperature<\/li>\n
- factory\/device1\/motorspeed<\/li>\n<\/ul>\n
Related Topics<\/strong><\/h3>\n
- \n
- How MQTT works?<\/a><\/li>\n
- MQTT \u2013 Connect to Broker\n
- \n
- Connect to Eclipse public MQTT Server<\/a><\/li>\n
- Connect to Mosquitto MQTT server on local Windows machine<\/a><\/li>\n<\/ul>\n<\/li>\n
- MQTT Topics<\/a><\/li>\n
- MQTT Publish<\/a><\/li>\n
- MQTT Subscribe<\/a><\/li>\n
- MQTT Quality of Service (QoS)<\/a><\/li>\n
- MQTT \u2013 Keep Alive with PINGREQ and PINGRESP<\/a><\/li>\n
- Install MQTT broker Mosquitto in Windows<\/a><\/li>\n
- Mosquitto Broker \u2013 Enable user authentication<\/a><\/li>\n
- MQTT Broker connection with user name and password<\/a><\/li>\n<\/ul>\n
MQTT Topic Wildcards<\/strong><\/h3>\n
Clients can subscribe to MQTT topics using wildcards which cane be single-level or multi-level. Wildcards can only be used for subscribing to topics, not for publishing topics.<\/p>\n
Single-level Wildcard<\/strong>: ‘+’ symbol is used to subscribe for single-level wildcards.<\/p>\n
Example of single-level wildcard topic,<\/p>\n
office\/groundfloor\/+\/temperature<\/p>\n
When clients subscribe to above topics with single-level topics, they will subscribe messages for below topics<\/p>\n
office\/groundfloor\/room1\/temperature<\/p>\n
office\/groundfloor\/room2\/temperature<\/p>\n
office\/groundfloor\/room3\/temperature<\/p>\n
Multi-level Wildcard<\/strong>: ‘#’ symbol is used to subscribe for multi-level wildcards. They can be used only at the end of topics.<\/p>\n
Example if multi-level wildcard topic,<\/p>\n
office\/groundfloor\/room1\/#<\/p>\n
When clients subscribe to above topic with multi-level wildcard, they will receive all messages pubslished under offoce\/groundfloor\/room1<\/p>\n
office\/groundfloor\/room1\/temperature<\/p>\n
office\/groundfloor\/room1\/humidity<\/p>\n
office\/groundfloor\/room1\/noise<\/p>\n
Try the AT Command Tester<\/a> tool to create new topics and publish messages,<\/p>\n
- Connect to Mosquitto MQTT server on local Windows machine<\/a><\/li>\n<\/ul>\n<\/li>\n
- MQTT \u2013 Connect to Broker\n
- How MQTT works?<\/a><\/li>\n
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<\/a><\/p>\n