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Frontmatter

Frontmatter is a YAML/TOML/JSON metadata block placed at the top of a document, delimited by ---, commonly used by static site generators.

Purpose

To attach structured metadata before the body of a Markdown-like document, easing site generation and content management.

Mechanism

The document starts with ---, followed by YAML (or TOML/JSON) metadata, ends with ---, and the body follows. The parser separates frontmatter from the body. Jekyll, Hugo, and Astro use it widely.

Use cases

  • Astro/Hugo/Jekyll article metadata
  • Markdown blog frontmatter
  • Documentation site configuration
  • CMS content management

Examples

  • Input 
    ---
title: Hello
---
# Body
    Output 
    meta {title:"Hello"} + body

    YAML frontmatter

Common errors

A frontmatter syntax error breaks parsing
Check it with a validator for the corresponding format

Related terms

YAML
YAML (YAML Ain't Markup Language) is a configuration-oriented data serialization format using indentation for hierarchy, supporting comments and references, and better suited to hand editing than JSON.
GLOSSARY
TOML
TOML (Tom's Obvious, Minimal Language) is a configuration-oriented format representing data with tables and key-value pairs, with explicit semantics and no implicit type inference.
GLOSSARY
JSON
JSON (JavaScript Object Notation) is a lightweight data interchange format based on JavaScript object literals, using key-value pairs and arrays.
GLOSSARY
YAML Frontmatter
YAML frontmatter is the --- delimited YAML block at the top of a Markdown file that stores document metadata (title, date, tags).
GLOSSARY

References