Markdown frontmatter explained

Frontmatter is a small block of metadata at the top of a Markdown file. Here is what it is, the YAML syntax it uses, and how MD-Vis displays it.

Frontmatter is a block of key/value metadata placed at the very top of a Markdown document, fenced by triple dashes (---). Static-site generators and note apps use it to store a title, date, tags and other fields without cluttering the body.

Basic syntax

---
title: My Document
author: Jane Doe
date: 2026-06-19
draft: false
tags: [markdown, mermaid, export]
---

# My Document

The body starts here.

Supported value types

• Strings, with or without quotes.
• Numbers and booleans (true / false).
• Lists, inline ([a, b]) or as indented - items.
• Nested maps via indentation.
• Multi-line text using block scalars (>- folded or | literal).

How MD-Vis renders it

When a document begins with a frontmatter block, MD-Vis parses it and shows a tidy, collapsible Frontmatter panel above the rendered content — lists become chips, nested maps are laid out clearly — and the metadata is stripped from the body so it does not appear as stray text. Paste a file with frontmatter into the editor to see it.