> ## Documentation Index
> Fetch the complete documentation index at: https://wundergraphinc-brendan-add-sof-link.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Create Feature Subgraph

> How to create a feature subgraph.

## Description

Create a feature subgraph based on an existing subgraph for your federated graph within the specified (otherwise "default") namespace. A feature subgraph is an "override" of an existing subgraph. One or more feature subgraphs are used to compose a [feature flag](/cli/feature-flags).

## Minimum Requirements

| Package                 | Minimum version                                                                |
| ----------------------- | ------------------------------------------------------------------------------ |
| [wgc](/cli/intro)       | [0.58.0](https://github.com/wundergraph/cosmo/compare/wgc@0.57.7...wgc@0.58.0) |
| [router](/router/intro) | [0.95.0](https://github.com/wundergraph/cosmo/releases/tag/router%400.95.0)    |

## Usage

<Note>
  A feature subgraph does not function in isolation. One or more feature subgraphs must compose a [feature flag](/cli/feature-flags), which itself must be enabled to take effect.
</Note>

```bash theme={null}
wgc feature-subgraph create my-feature-subgraph --subgraph my-subgraph --routing-url http://localhost:4000
```

The alias for `feature-subgraph` is `fs`.

Note that unless specified by the `--namespace` parameter, the namespace will be automatically passed as "default".

<Note>
  The type of the feature subgraph is determined by the type of the base subgraph. For example, if the base subgraph is a plugin subgraph, the feature subgraph will also be a plugin subgraph.
</Note>

## Parameters

* `<name>`: The name of the feature subgraph to create. Must be unique among all subgraphs and feature subgraphs within the specified (otherwise "default") namespace.

## Required Options

<Note>
  If the base subgraph does not exist in the specified (otherwise "default") namespace, the command will fail.
</Note>

`--subgraph`: The name of the existing base subgraph for which the feature subgraph is to be created.

## Options

<Info>
  Feature subgraphs do not use labels directly; labels are set by the [feature flag](/cli/feature-flags) that the feature subgraph(s) compose.
</Info>

<Note>
  If the base subgraph is not a plugin subgraph, the routing url is required.
</Note>

* `-r , --routing-url`: Set the URL for the subgraph's data source. This URL defines the endpoint from which the subgraph will fetch data.

* `-n, --namespace` : The namespace of the feature subgraph (defaults to "default"). Returns an error if the feature flag does not exist in that namespace.

* `--subscription-url:` Use a different URL for subscription requests. If no subscription URL is provided, the router URL is used for subscriptions.

* `--subscription-protocol:` Set a protocol to use for subscriptions. The available options are:

  * `ws` (default): Negotiate an appropriate protocol over websockets. Both `graphql-ws` and `subscription-transport-ws` are supported.

  * `sse`: Use Server-Sent Events with a GET request.

  * `sse_post`: Use Server-Sent events with a POST request.

## Examples

* Create the feature subgraph "my-feature-subgraph" based on the existing subgraph "my-subgraph" in the namespace "prod".

```bash theme={null}
wgc feature-subgraph create my-feature-subgraph \
	--subgraph my-subgraph \
	--namespace prod \
	--routing-url http://localhost:4000
```