--- aliases: - front matter - Advanced topics/YAML front matter --- While most of the text in a note is meant to be read by a human, _metadata_ is text that's meant to be easily readable by a program, for example a [[Community plugins|community plugin]] or Obsidian itself. You can add metadata to your notes by adding a block on the first line of your note. The block must start and end with three hyphens (`---`). For example, the following note contains two pieces of metadata, `tag` and `publish`: ```yaml --- tag: journal publish: false --- # Daily note Today I learned about front matter. ``` > [!tip] > By default, metadata is only visible in the [[Read and edit modes|editing view]]. > > To display metadata in reading view: > > 1. Open **Settings**. > 2. Under **Editor**, enable **Show frontmatter**. ## Metadata format [YAML](https://yaml.org/) is a widely used configuration format that's readable by both humans and machines. Each piece of metadata consists of a _key_ and a corresponding _value_. Keys are separated from their values by a colon followed by a space: ```yaml --- key: value --- ``` While the order of each key-value pair doesn't matter, each key must be unique within a note. For example, you can't have more than one `tag` key. Values can be text, numbers, true or false, or even collections of values (arrays). ```yaml --- title: A New Hope year: 1977 favorite: true cast: - Mark Hamill - Harrison Ford - Carrie Fisher --- ``` > [!tip] JSON metadata > While we recommend using YAML to define metadata, you can also define metadata using [JSON](https://www.json.org/): > > ```md > --- > { > "tag": "journal", > "publish": false > } > --- > ``` ## Predefined metadata Obsidian comes with of a set of predefined keys: | Key | Description | |-|-| | `tag` | See [[Editing and formatting/Tags\|Tags]]. | | `tags` | Alias for `tag`. | | `alias` | See [[Aliases]]. | | `aliases` | Alias for `alias`. | | `publish` | Used by [[Introduction to Obsidian Publish\|Obsidian Publish]] to [[Publish and unpublish notes#Automatically select notes to publish\|automatically select notes to publish]]. | | `cssclass` | Allows you to style individual notes using [[CSS snippets]]. |