---
title: Using FxPlug APIs
framework: professional-video-applications
role: article
path: professional-video-applications/using-fxplug-apis
---

# Using FxPlug APIs

## Using FxPlug APIs

Using FxPlug APIs Use various FxPlug APIs to communicate with host apps like Motion or Final Cut Pro.

Overview

When your plug-in needs to access a host’s capabilities, use the associated FxPlug API that corresponds to the capability you need to access.

Your plug-in can instantiate host API objects that let you communicate and interact with the host application to extend your plug-in’s functionality. A host API implements methods that your plug-in can call to get a specific functionality—such as requesting information about a video stream, or reading a parameter value from the UI.

A host API is analogous to a callback suite in other plug-in architectures, but is implemented as a protocol in FxPlug.

FxPlug defines host protocols for common tasks, including:

-     Requesting layer information -     Converting between canvas and object coordinate spaces -     Building a list of plug-in parameters -     Getting and setting parameter values -     Evaluating input images at arbitrary times

> Note >  Not all host applications support all of the host API protocols in FxPlug. Make sure your plug-in requests the host API object before invoking its methods.