> ## 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.

# Introspect

> Introspects a subgraph.

## Usage

```bash theme={null}
npx wgc subgraph introspect --routing-url [url] --header [headers...]
```

## Description

The `npx wgc subgraph introspect` command allows you to introspect a subgraph and returns the schema of the subgraph.

## **Options**

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

  * Example: `--routing-url http://localhost:4001/graphql`

* `--header`: The headers to apply when the subgraph is introspected. This is used for authentication and authorization. The headers are passed in the format \<key>=\<value> \<key>=\<value>. Use quotes if there exists space in the key/value.

  * Example: `--header Authorization='Bearer <token>'`

* `-o, --out` : Destination file for the SDL. Prints to standard output if not provided.

## **Example**

1. Introspect a subgraph with routing URL "[http://localhost:4001/graphql](http://localhost:4001/graphql)":

   ```bash theme={null}
   npx wgc subgraph introspect --routing-url http://localhost:4001/graphql
   ```