> ## Documentation Index
> Fetch the complete documentation index at: https://docs.appsignal.com/llms.txt
> Use this file to discover all available pages before exploring further.

# AppSignal for JavaScript configuration

## Setting up AppSignal

To configure AppSignal for front-end JavaScript, we recommend creating an `appsignal.js` file with the AppSignal config in your project's root or `src` directory.
Then require or import the configuration file from the app's code before any other packages are required or imported.

In the example below, there is an `appsignal.js` file in the root of the applications directory. On line 8 we've added the `namespace` config option.

<CodeGroup>
  ```javascript JavaScript theme={null}
  // For ES Module via npm/yarn, or with import maps
  import Appsignal from "@appsignal/javascript";
  // For CommonJS module via npm/yarn
  const Appsignal = require("@appsignal/javascript").default;
  // With the JSPM.dev CDN
  import Appsignal from "https://jspm.dev/@appsignal/javascript";

  const appsignal = new Appsignal({
    key: "<YOUR FRONTEND API KEY>",
  });

  module.exports = { appsignal };
  ```
</CodeGroup>

## Customize the configuration

You can customize the error reporting from your application with the [Front-end configuration options](/front-end/configuration/options).

Here's an example of how the [namespace option](/front-end/configuration/options#namespace) is customized.

<CodeGroup>
  ```diff Example namespace option theme={null}
   const appsignal = new Appsignal({
     key: "<YOUR FRONTEND API KEY>",
  +  namespace: "frontend", // Configure the AppSignal namespace for front-end errors in this app
   });
  ```
</CodeGroup>

## Require the AppSignal configuration

Once you're done with your application's config, require the `appsignal.js` file at the very top of your application's main file, like in the example below:

<CodeGroup>
  ```javascript JavaScript theme={null}
  // Place this at the top
  // Import the file created in the previous step
  const { appsignal } = require("./appsignal"); // Update to the location used in the previous step

  // Place your app code below this
  ```
</CodeGroup>

After your application loads the AppSignal JavaScript library, make sure to follow all the [steps in the installation guide](/front-end/installation), adding [integrations](/front-end/integrations), adding [plugins](/front-end/plugins), and customize your [configuration](/front-end/configuration/options).