# Using Mashups

One approach to reducing the amount of data in Salesforce is to maintain large data sets in a different application, and then make that application available to Salesforce as needed. Salesforce refers to such an arrangement as a *mashup* because it provides a quick, loosely coupled integration of the two applications. Mashups use Salesforce presentation to display Salesforce-hosted data and externally hosted data.

Salesforce supports the following mashup designs.

- External Website

  - : The Salesforce UI displays an external website, and passes information and requests to it. With this design, you can make the website look like part of the Salesforce UI.

- Callouts

  - : Apex code allows Salesforce to use Web services to exchange information with external systems in real time.

Because of their real-time restrictions, mashups are limited to short interactions and small amounts of data.

See [Apex Developer Guide](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_dev_guide.htm).

## Advantages of Using Mashups

- Data is never stale.
- No proprietary method needs to be developed to integrate the two systems.

## Disadvantages of Using Mashups

- Accessing data takes more time.
- Functionality is reduced. For example, reporting and workflow do not work on the external data.