# Referencing Another API Specification

![Referencing Another API Specification](https://github.com/stoplightio/docs/blob/develop/assets/gifs/modeling-ref-other-spec.gif?raw=true)

## What

Referencing another specification allows for cleaner and more organized code. Some use cases are as follows:

* Generate API documentaion in Hubs
* De-duplicate common structures like responses or shared parameters in Modeling
* Test a connected API specification in Scenarios
* Setup a mock server for an API in Prism

## How

1.  Choose the **source**

    * This File

    * This Project

      * Select a **file**

    * Shared/Common

    * External URL

      * Enter a valid **URL** to an existing specification

2.  Select a **target**, if required

3.  Confirm your choice. (Only required if there is a confirm button)

4.  View the referenced specification by clicking the book icon

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**Related Links**

* [Reference other Sources](/documentation/referencing-other-data-sources)
* [API Models](/modeling/modeling-with-openapi/api-models)
* [Shared Parameters and Responses](/modeling/modeling-with-openapi/shared-parameters-and-responses)