# Entrypoints
An "entrypoint" is any HTML, JS, or CSS file that needs to be bundled and included with your extension, which will be loaded and executed by the browser.
## Defining Entrypoints
In WXT, you create an entrypoint by adding a file to the `entrypoints/` directory.
```
└─ entrypoints/
├─ background.ts
├─ content.ts
├─ injected.ts
└─ popup.html
```
Some entrypoint filesname patterns are reserved by WXT and effect how the manifest is generated.
- `popup` adds an `action` to the manifest
- `background` adds a background script/service worker
- `*.content.ts` adds a content script
- ...
> For a full list of recognized filenames, see the the [Entrypoints Directory guide](/guide/directory-structure/entrypoints/background).
Any other files, whether JS, CSS, or HTML, is considered "unlisted". Unlisted files, like `injected.ts` from above, are just bundled to the output directory and not added to the manifest. You can still access or load them at runtime.
## Entrypoint Options
Most entrypoints allow customizing their options in the file you define them in. This differs from regular web extension development, where all options are placed in the `manifest.json`.
WXT looks for custom options in the entrypoint, and adds them to the manifest when generated.
In HTML files, options are listed as `meta` tags:
```html
```
In TS files, options are apart of the file's default export:
```ts
export default defineContentScript({
matches: ['*://*.google.com/*'],
runAt: 'document_start',
main() {
// ...
},
});
```
:::info
All options for each entrypoint type is listed in the [entrypoints directory docs](/guide/directory-structure/entrypoints/background).
:::