# How to select variables on Data Stream import DocButton from '~/components/webkit/DocButton.vue'; The data streamed by **Data Stream** to your configured connectors is decided according to the variables you choose to use. Each variable provides a specific information or set of information and is associated with a specific data source. You can find all available variables, their descriptions, and examples in the [data source](/en/documentation/products/observe/data-stream/#data-sources) reference. You have the option of using a [pre-set template](https://www.azion.com/en/documentation/products/guides/data-stream-custom-template/), with an option for each available data source, or using a [custom template](https://www.azion.com/en/documentation/products/guides/data-stream-custom-template/), so you can decide which variables will be streamed. --- ## Using a pre-set template If you're configuring a connector to receive as much information as possible from, for example, an application, using a pre-set template could be the best choice. In this case, you'll use the **Applications + WAF Event Collector** template via Azion Console or the **http** template via API. --- ## Using a custom template If you're configuring a connector with a specific purpose, such as, for example, analyzing logs related to the status of your application, you can configure: - A custom template via Azion Console, by editing the selected **Data Set**. - A **Custom Template** via Real-Time Manager. - A **temaplate_model** via API. Creating a customizable template allows you to choose from the [list of available variables](/en/documentation/products/observe/data-stream/#data-sources) the ones you want to use. In this case, you could use, for example, the variables `$status`, `$proxy_status`, and `$upstream_status`. You'll also be able to edit the stream and add new variables if you find they aren't providing all the information you require.