> ## Documentation Index > Fetch the complete documentation index at: https://docs.zeotap.com/llms.txt > Use this file to discover all available pages before exploring further. # Google Pub/Sub ## Overview Google Pub/Sub is an asynchronous and scalable messaging service that decouples services producing messages from services processing those messages. Pub/Sub is used for streaming analytics and data integration pipelines to ingest and distribute data. ## Prerequisites Ensure that you have the following details available before starting the integration: * Project Id * Topic Id * Authentication ### Project Id A Project ID is a unique string that differentiates your project from all others on Google Cloud. You can use the [Google Cloud console](https://cloud.google.com/resource-manager/docs/creating-managing-projects?hl=en\&ref_topic=6158848\&visit_id=638040066804795299-2594272843\&rd=1) to generate a Project ID. You can find the Project ID in the Google Cloud console - [Dashboard page](https://console.cloud.google.com/home). In the below example, the Project name is **My Sample Project** and the Project ID is **my-sample-project-191923**.

### Topic Id In the Google Cloud console, go to the [**Pub/Sub**](https://console.cloud.google.com/cloudpubsub/topicList?_ga=2.230005471.2138624224.1673155280-188740464.1653481288) page > **Topics**. A list of all the topics created appears. Copy the relevant Topic Id and use it for the destination setup.

### Authentication The authentication method for the Pub/Sub destination can be **Refresh Token** or **Service Account**. Provide the required details based on the authentication method you choose. #### Refresh Token Authentication To authenticate using a Refresh Token, you need the following details: * Client ID * Client Secret * Refresh Token For this integration, if you decide to perform the authentication through the **Refresh Token**, then Zeotap CDP requires the **Client ID**, **Client Secret**, and **Refresh Token** to establish a connection with the Pub/Sub destination where you want to send data. In Google Cloud, these unique credentials can be used to authorise applications or services, such as Pub/Sub, through OAuth 2.0. For detailed steps to generate them, refer to [Google Pub/Sub documentation](https://developers.google.com/google-ads/api/docs/oauth/playground). In the [Refresh Token generation steps](https://developers.google.com/google-ads/api/docs/oauth/playground#generate_tokens), add the **Cloud Pub/Sub API v1** scope when specifying API scopes, as shown in the image below.

#### Service Account Authentication To authenticate using a Service Account, you must assign the **Pub/Sub Publisher** role to the "[pub-sub-publisher@dcr-orchestration-prod.iam.gserviceaccount.com](mailto:pub-sub-publisher@dcr-orchestration-prod.iam.gserviceaccount.com)" service account within Pub/Sub as shown below.

## Destination Setup Once you have taken care of the prerequisites mentioned above, you can proceed to [creating workflow in Journeys](https://docs.zeotap.com/articles/orchestrate-customer/create-a-workflow) (Zeotap CDP). After you have applied filters or added conditions for your users in Journeys as mentioned in [Create a Workflow](https://docs.zeotap.com/articles/orchestrate-customer/create-a-workflow), you can activate them in Google Pub/Sub in the **Send to Destinations** node as shown below.

A new window appears, where you can set up your destination. You can use an already existing destination from the list of available Destinations or create a new one by clicking **+ Add New Destination**.

**Note:** To use an existing destination for activation in Journeys, click [here](/articles/integrate-customer/google-pub-sub#h2__290574186). ### Add New Destination Perform the following steps to add a new destination: Click **Add New Destination.** Search for **Google Pub/Sub.** Click **Google Pub/Sub** and enter a name for the Destination. Enter the **Instance**, which is an internal field for the Destination. Provide the **Project Id** and **Topic Id** obtained from your Google Cloud. [Learn more](/articles/integrate-customer/google-pub-sub#h4_2023180516)

Choose either **Refresh Token** or **Service Account** as your Authentication method, based on your requirement. a. If you choose **Refresh Token**, then provide the **Client Id**, **Client Secret** and **Refresh Token** details in the respective fields. [Learn more](/articles/integrate-customer/google-pub-sub#h4__107804704)

b. If you choose **Service Account**, then the following **Google** **Service Account** is displayed. Ensure to provide "**Pub/Sub Publisher**" role to this service account within Pub/Sub. [Learn more](/articles/integrate-customer/google-pub-sub#h3__1953899986) **Service Account:** [pub-sub-publisher@dcr-orchestration-prod.iam.gserviceaccount.com](mailto:pub-sub-publisher@dcr-orchestration-prod.iam.gserviceaccount.com)

In the mapping screen that appears, under **Choose your Action**, select **Send identifiers to Google Cloud PubSub in realtime** as the action for sending data from the workflow created in Journeys. Under **Map the Fields**, use **+ Add Mapping Field** to add any custom field that you wish to send to Google Pub/Sub. Ensure that you map at least one attribute. Otherwise, the data does not flow to the Pub/Sub destination.

Once the mapping is complete, click **Create Destination**. The destination is created and made available for activation on Journeys as shown below.

## Activate the Destination on Journeys After creating a destination, next, you need to link it in the **Send to Destination** node within the workflow, as explained below. In the workflow, click **+** and choose **Send to Destinations**.

Choose the destination from the list of available destinations by using the search feature. Under the **Destination Details** tab, based on the authentication type you have chosen, the **Instance,** **Project Id, Topic Id, Authentication (Refresh Token/Service Account) and other fields** as shown in the image below automatically populates based on the values that you have entered while creating the destination. However, you need to provide an **Audience Name** to save the Destination.

Under the **Destination Settings** tab, choose the action and mapping as per your requirement.

Upon clicking **Save Destination**. The destination is attached as shown in the image below.

Click **Add Destinations** at the bottom right corner of the screen. Note that you can also add multiple destinations at this step if needed. The linked Destinations appear in the **Send to Destinations** node within the workflow as shown below. Further, you can then build and customise your workflow as needed by clicking '+' . Note that you must enter a name for your workflow in the provided text box to save it.

After adding conditions and filters for users, choose one of the following options: * **Save Draft**: Enables you to revisit and edit the workflow before publishing. * **Next: Re-entry Condition**: Determines whether a user can re-enter the same workflow. After defining the re-entry criteria, click **Publish Workflow**. The workflow appears in the Workflow listing screen with a **Published** status.