Is there any max limit for the number of topics in MQTT?

There is no such limitation as per the spec. But this is very much governed by the hardware capability where the broker is being run.

Most of the Platforms like Bevywise IoT Platform handle this by having a distributed architecture and having multiple front end brokers to handle this.

Having said this, Application developers should keep an eye on how they define their topics.

Group devices with relevant topics and some unique Identifier into the topic
Have a common topic subscription for all devices if you look for some broadcast or define multi level topics to use the # based propagation
Keep the complete end to end solution in mind to define topics and the data propagation , analysis while defining topics and data grouping.

Hope this helps.

Reference : https://www.quora.com/Is-there-any-maximum-limit-for-the-number-of-topics-in-an-MQTT-server

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Manoj Bhoir7y ago
There is no such limitation as per the spec. But this is very much governed by the hardware capability where the broker is being run.

Most of the Platforms like Bevywise IoT Platform handle this by having a distributed architecture and having multiple front end brokers to handle this.

Having said this, Application developers should keep an eye on how they define their topics.
- Group devices with relevant topics and some unique Identifier into the topic
- Have a common topic subscription for all devices if you look for some broadcast or define multi level topics to use the # based propagation
- Keep the complete end to end solution in mind to define topics and the data propagation , analysis while defining topics and data grouping.
Hope this helps.

Reference : https://www.quora.com/Is-there-any-maximum-limit-for-the-number-of-topics-in-an-MQTT-server
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