# SubFlows SubFlow in cosmocloud provides modular approach to build reusable piece of flow. It helps you to build a piece of code once and plug it in existing flow. ## Create SubFlow * Navigate to **Application Layer -> SubFlows** in your Cosmocloud project. * Click on **Create SubFlow** button * Add your SubFlow name as well as add the **Arguments** your SubFlow will receive from the calling Flow (an API or other SubFlow). ## Understanding Arguments

* **Toggle :** This is used to mark if argument is `required` or `optional` * **Argument key :** argument name to be received * **Argument type :** It specify what type of value is expected * **Default :** It specify default value if user didn't enter value. (optional) ## How to use SubFlow SubFlow in cosmocloud is an isolated component which means every value that you want to access in SubFlow needs to passed as an argument. #### Understanding SubFlow node * To execute this SubFlow in an existing API, you can use `Execute SubFlow` node

* You need to select the SubFlow which you need to execute and also pass required arguments.

* Arguments will be passed in as keys and values. These values are case sensitive so make sure enter correct terms.