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# Connections - MQTT

Under `Connections`, you can add and manage connections to external interfaces. For example, you can use MQTT to integrate IoT devices, sensors and industrial control systems. A corresponding trigger is available in the flows, which can receive and process data from the MQTT interface.

| 💡 Using this connection requires knowledge of MQTT.

||| ❗️ The MQTT connection is subject to a fixed rate limit of 50 messages per second. Any additional messages will be ignored without acknowledgement.

In addition to MQTT, connections for [WDX3](https://docs.groupalarm.com/en/article/connections-wdx3-12sj3m4/) and [IMAP](https://docs.groupalarm.com/en/article/connections-imap-1vrl180/) can also be set up.

1️⃣ Each connection can be switched on and off in the overview using the toggle. The current status of the connection is displayed on the right-hand side.

2️⃣ The functions at the bottom of a connection provide you with more in-depth monitoring and editing options for that connection.

* `LOG` shows you the connection log. For example, when a connection was established or terminated.
* Clicking `EDIT` takes you to the connection’s edit view. This is the same as the view shown during the [initial setup of a connection](/en/article/connections-mqtt-1kcat4t/#3-create-a-connection) and allows you, for example, to change the password or replace the certificate.
* The `LIVE` view shows you in real time which data is being exchanged via the interface.
* You can use `DELETE` to completely remove a connection that is no longer required.

![](https://storage.crisp.chat/users/helpdesk/website/-/9/1/f/e/91fefd8b4b0ac000/verbindungenmqtt1en_11lw24a.png)

### Create a connection

If you wish to create a new connection, the following input form will appear.

1️⃣ Use the `Name` and `Description` fields to name the connection you are setting up and add a description. This will help you identify the connection in the overview later on, should you set up multiple connections.

2️⃣ In the `Type` drop-down menu, you can specify the type of connection. In the example shown, this is MQTT.

3️⃣ Here, you can specify the protocol, the URL of your MQTT broker and the corresponding port.

4️⃣ `Username` and `Password` may be required for authentication with the server when setting up an MQTT connection. To view the password, click on the eye icon to the right of the password input field. You can also optionally upload the certificate.

5️⃣ Under `Topics`, you can define up to 5 topics (such as ‘Temperature’)

![](https://storage.crisp.chat/users/helpdesk/website/-/9/1/f/e/91fefd8b4b0ac000/verbindungenmqtt2en_1bw9hz0.png)