# Front Matter in VuePress
Any markdown file that contains a YAML front matter block will be processed by gray-matter. The front matter must be the first thing in the markdown file and must take the form of valid YAML set between triple-dashed lines. Here is a basic example:
---
title: Blogging Like a Hacker
lang: en-US
---
Between these triple-dashed lines, you can set predefined variables (see below for a reference), or even create custom ones of your own. These variables will then be available to you to access using $frontmatter at the rest of the page, plus all custom and theming components.
::: tip Front matter variables are optional in VuePress. :::
# Alternative Front Matter Formats
In addition, VuePress also supports JSON or TOML front matter.
JSON front matter needs to start and end in curly braces:
---
{
"title": "Blogging Like a Hacker",
"lang": "en-US"
}
---
TOML front matter needs to be explicitly marked as TOML:
---toml
title = "Blogging Like a Hacker"
lang = "en-US"
---
# Predefined Variables
# title
- Type:
string - Default:
h1_title || siteConfig.title
Title of current page.
# lang
- Type:
string - Default:
en-US
Language of current page.
# description
- Type:
string - Default:
siteConfig.description
Description of current page.
# layout
- Type:
string - Default:
Layout
Set the layout component of the current page.
# permalink
- Type:
string - Default:
siteConfig.permalink
Refer to: Permalinks.
# metaTitle
- Type:
string - Default:
`${page.title} | ${siteConfig.title}`
Override the default meta title.
# meta
- Type:
array - Default:
undefined
Specify extra meta tags to be injected:
---
meta:
- name: description
content: hello
- name: keywords
content: super duper SEO
---
# Predefined Variables Powered By Default Theme
# navbar
- Type:
boolean - Default:
undefined
See: Default Theme Config > Disable the Navbar.
# sidebar
- Type:
boolean|'auto' - Default:
undefined