# App Config: Basics ## base - Type: `string` - Default: `/` The base URL the site will be deployed at. You will need to set this if you plan to deploy your site under a sub path, for example, GitHub pages. If you plan to deploy your site to `https://foo.github.io/bar/`, then you should set base to `'/bar/'`. It should always start and end with a slash. The `base` is automatically prepended to all the URLs that start with `/` in other options, so you only need to specify it once. ```js module.exports = { base: '/base/' } ``` ## lang - Type: `string` - Default: `en-US` The `lang` attribute for the site. This will render as a `` tag in the page HTML. Note that the `lang` attribute will only be added when building the site via `vitepress build`. You will not see this rendered during `vitepress dev`. ```js module.exports = { lang: 'en-US' } ``` ## title - Type: `string` - Default: `VitePress` Title for the site. This will be the prefix for all page titles, and displayed in the navbar. ```js module.exports = { title: 'VitePress' } ``` ## Description - Type: `string` - Default: `A VitePress site` Description for the site. This will render as a `` tag in the page HTML. ```js module.exports = { title: 'A VitePress site' } ```