Front matter is metadata embedded at the top of a file that is used to control various aspects of how Jekyll processes the file. Front matter must be placed at the very top of a file and must be the first thing in the file.
There are three types of front matter that Jekyll recognizes:
- YAML front matter
- JSON front matter
- TOML front matter
YAML front matter is the most common type of front matter and is used to specify a variety of options, such as the title, author, and date of a post.
JSON front matter is less common, but can be used to specify more complex data structures, such as those used in Jekyll's data files.
TOML front matter is the least common type of front matter and is used to specify options in a more terse way than YAML or JSON.