---
title: Subscribe to Topics with Flows
slug: litmusedge/how-to-guides/flows-guides/subscribe-to-topics-with-flows
description: You can use Flows to subscribe to individual topics or use wildcards to subscribe to multiple topics.
docTags: 
createdAt: 2023-12-14T16:01:02.701Z
---

You have the following options for subscribing to topics in Flows. 

# Subscribe to a Single Topic

The following steps describe how to subscribe to a single topic from a connected DeviceHub device. See the following to learn more:

- [Connect a device](docId\:pal6ABPZbrimdU9LvGJ30)
- [Add Tags](docId\:XgWOkQbTPevII7OR82LL0)

**To subscribe to a single topic:**

1. Get the topic name to configure the *DataHub Subscribe* node in Flows.
   - Go to **DeviceHub** and select the **Tags **pane from the navigation menu.
   - Click the **Copy **icon next to the *RAW Topic* from which you wish to receive data.
     ![](https://api.archbee.com/api/optimize/SSUUxKZUk9bFTEPNn_6Zo/nJmhVP4Ac7_GWSdBcd0Lm_aa.png "Litmus Edge DeviceHub Page")
2. In the navigation menu, click **Flows Manager**.
3. To access an existing flow canvas, click the **Go To Flow Definition **icon next to the flow status. For creating a new flow, refer to *Step 2: Create Individual Flow *in [Create a Flow](docId\:wh4ZihWF0PwMRYRbAZbco)  to learn more.
   The *Flow* canvas opens in a new browser tab.
   ![](https://api.archbee.com/api/optimize/SSUUxKZUk9bFTEPNn_6Zo/-Sz2k0jom4DrMqIgt_IBY_c.png "Go To Flow Definition icon")
4. Drag the **DataHub Subscribe node** and **debug node** on the canvas and connect them.
   ![](https://api.archbee.com/api/optimize/SSUUxKZUk9bFTEPNn_6Zo/FwWYGnQPIqeg0rCCSTgFN_aaaa.png "The Debug and DataHub Subscribe nodes")
5. Double-click the **DataHub Subscribe **node to open the *Edit DataHub Subscribe* node dialog box. Configure the node by following these steps:
   - Paste the topic name previously copied into the *Topic *field. 
   - If needed, configure the Datahub Subscribe connection. See the *Step 3: Configure Connector Nodes* section in [Create a Flow](docId\:wh4ZihWF0PwMRYRbAZbco) to learn more. 
   - Enter a name in the *Name *field and click **Done**.
     ![](https://api.archbee.com/api/optimize/SSUUxKZUk9bFTEPNn_6Zo/CvHmyQFBjpNVpzaQmK76v_aws.png "The debug node connected to existing flow")
6. To save the flow, click **Deploy**. 
7. Expand the message window beneath the flow.
   ![](https://api.archbee.com/api/optimize/SSUUxKZUk9bFTEPNn_6Zo/PdO3lIPUKNYpR9eiOS-2g_wda.png "The message window")
8. Click the **Debug **icon to view the data output.
   ![](https://api.archbee.com/api/optimize/SSUUxKZUk9bFTEPNn_6Zo/EU6xcVQGYQIVH7p2AgVFy_wwww.png "The debug icon")
9. Review the data payload in the message window.
   ![](https://api.archbee.com/api/optimize/SSUUxKZUk9bFTEPNn_6Zo/L_YueXsA7xy9G7MW7WIYY_waq.png "Successful write message")

# Subscribe to Multiple Topics using Wildcards

Use **Wildcards **to subscribe to multiple topics at once.

## Wildcard Usage

`>`** Wildcard Character**: Use the `>` wildcard character to subscribe to messages from multiple tags. Example: `devicehub.alias.>` will subscribe to every topic in the DeviceHub.

`*`** Wildcard Character**: Use the `*` wildcard character to match a single topic between `.` characters in tags. Example: `devicehub.alias.*.*` matches topics with two-character sequences after each of the two`.` characters.

:::hint{type="info"}
**Note: **Using just the `>` wildcard character subscribes to all topics, which can cause slowdowns when sending data to databases or clouds. Consider using [Function Nodes](docId\:hqkB5sh0ow9c_magqsrcc) to trim data or file nodes for efficiency.
:::

## Use Wildcards to Subscribe to Multiple Topics

To subscribe to multiple topics in flows, replace the topic name in step five of "Subscribe to a Single Topic" with the information about topic wildcards as below. 

**To use wildcards to subscribe to multiple topics: **

1. Complete steps 1-5 from "Subscribe to a Single Topic" above. 
2. Replace the topic name with the desired wildcard-based topic. 
   **Syntax Examples:**
   `devicehub.alias.>` (Subscribe to all topics in DeviceHub)
   `devicehub.alias.{Device_ID}.>` (Subscribe to all tags from a specific DeviceHub device)
   `devicehub.alias.*.test_tag` (Subscribe to all tags named test\_tag from every DeivceHub device)
   ::Image[]{src="https://api.archbee.com/api/optimize/SSUUxKZUk9bFTEPNn_6Zo/xngWzX0aI46LdbNvKhToy_aawwaa.png" size="50" width="538" height="321" position="center" caption="Edit Datahub Subscribe node dialog box" showCaption="true"}
3. Click **Done** and save the flow by clicking the **Deploy **button at the top-right corner of the screen.
4. Expand the message window beneath the flow.
   ![](https://api.archbee.com/api/optimize/SSUUxKZUk9bFTEPNn_6Zo/qUN5U9gp0rXYkLw_78Q8K_wda.png "The message window")
5. Click the **Debug **icon to view the data output.
   ![](https://api.archbee.com/api/optimize/SSUUxKZUk9bFTEPNn_6Zo/ty5MlM2L2Y6XYo16cioXI_wwww.png "The debug icon")
6. Review the data payload in the message window. 
   ![](https://api.archbee.com/api/optimize/SSUUxKZUk9bFTEPNn_6Zo/Nq0jhivSWKhi8iRUJYOJQ_image.png "Data output from all Topics")