**Front matter** allows you to keep metadata attached to an instance of a [content type][]---i.e., embedded inside a content file---and is one of the many features that gives Hugo its strength.
There are a few predefined variables that Hugo is aware of. See [Page Variables][pagevars] for how to call many of these predefined variables in your templates.
: an array of one or more aliases (e.g., old published paths of renamed content) that will be created in the output directory structure . See [Aliases][aliases] for details.
: the datetime at which the content should no longer be published by Hugo; expired content will not be rendered unless the `--buildExpired` flag is passed to the `hugo` command.
: the layout Hugo should select from the [lookup order][lookup] when rendering the content. If a `type` is not specified in the front matter, Hugo will look for the layout of the same name in the layout directory that corresponds with a content's section. See ["Defining a Content Type"][definetype]
: used for creating links to content; if set, Hugo defaults to using the `linktitle` before the `title`. Hugo can also [order lists of content by `linktitle`][bylinktitle].
: an array of series this page belongs to, as a subset of the `series` [taxonomy](/content-management/taxonomies/); used by the `opengraph` [internal template](/templates/internal) to populate `og:see_also`.
: field name of the *plural* form of the index. See `tags` and `categories` in the above front matter examples. _Note that the plural form of user-defined taxonomies cannot be the same as any of the predefined front matter variables._
If neither `slug` nor `url` is present and [permalinks are not configured otherwise in your site `config` file](/content-management/urls/#permalinks), Hugo will use the filename of your content to create the output URL. See [Content Organization](/content-management/organization) for an explanation of paths in Hugo and [URL Management](/content-management/urls/) for ways to customize Hugo's default behaviors.
{{% /note %}}
### User-Defined
You can add fields to your front matter arbitrarily to meet your needs. These user-defined key-values are placed into a single `.Params` variable for use in your templates.
The following fields can be accessed via `.Params.include_toc` and `.Params.show_comments`, respectively. The [Variables][] section provides more information on using Hugo's page- and site-level variables in your templates.
You can assign content-specific `weight` in the front matter of your content. These values are especially useful for [ordering][ordering] in list views. You can use `weight` for ordering of content and the convention of [`<TAXONOMY>_weight`][taxweight] for ordering content within a taxonomy. See [Ordering and Grouping Hugo Lists][lists] to see how `weight` can be used to organize your content in list views.
## Override Global Markdown Configuration
It's possible to set some options for Markdown rendering in a content's front matter as an override to the [BlackFriday rendering options set in your project configuration][config].
## Front Matter Format Specs
* [TOML Spec][toml]
* [YAML Spec][yaml]
* [JSON Spec][json]
[variables]: /variables/
[aliases]: /content-management/urls/#aliases/
[archetype]: /content-management/archetypes/
[bylinktitle]: /templates/lists/#by-link-title
[config]: /getting-started/configuration/ "Hugo documentation for site configuration"
[content type]: /content-management/types/
[contentorg]: /content-management/organization/
[definetype]: /content-management/types/#defining-a-content-type "Learn how to specify a type and a layout in a content's front matter"
[lists]: /templates/lists/#ordering-content "See how to order content in list pages; for example, templates that look to specific _index.md for content and front matter."
[lookup]: /templates/lookup-order/ "Hugo traverses your templates in a specific order when rendering content to allow for DRYer templating."
[ordering]: /templates/lists/ "Hugo provides multiple ways to sort and order your content in list templates"
[outputs]: /templates/output-formats/ "With the release of v22, you can output your content to any text format using Hugo's familiar templating"
