# Audio extension (/en/realtime-media/marketplace/build/build-your-own-extension/audio-filter/web)

> For AI agents: see the complete documentation index at [llms.txt](/llms.txt).

The audio filters you create are easily integrated into apps to supply voice effects and noise cancellation.

      
  
      
  
      
  
      
## Understand the tech

An audio filter accesses voice data when it is captured from the user's local device, modifies it, then plays the updated data to local and remote video channels.

![Audio extension pipeline](https://web-cdn.agora.io/docs-files/1648464455901)

A typical transmission pipeline consists of a chain of procedures, including capture, pre-processing, encoding, transmitting, decoding, post-processing, and playback. To modify the voice or video data in the transmission pipeline, audio extensions are inserted into either the pre-processing or post-processing stage.

## Prerequisites

* A [supported browser](../../reference/supported-platforms.mdx).
* Physical media input devices such as a camera and a microphone.
* A JavaScript package manager such as [npm](https://www.npmjs.com/package/npm).
* A project to develop in.

## Project setup

* Start from the Web flow in [Quickstart - integrate an extension](../../quickstart-integrate.mdx).
* Prepare your extension package, bundler integration, and runtime registration flow.

## Create an audio extension

Implement the extension as a Web audio processing plug-in that can be installed and registered from your JavaScript application.

## Reference

* [Quickstart - integrate an extension](../../quickstart-integrate.mdx)