YAML Front Matter Editor
Edit page metadata while keeping your Markdown body intact.
Local processing · UTF-8 Markdown · Up to 100,000 characters and 400 KiB.
Format reference: Jekyll front matter documentation. Fields are not checked against a specific site generator’s configuration.
About YAML Front Matter Editor
Load a Markdown file or paste its source, edit the YAML metadata at the start, and download a new copy. The original source remains available. Processing stays in your browser; nothing in the Markdown is rendered or executed.
Frequently Asked Questions
Only a literal --- line at the very start, optionally after a UTF-8 BOM, followed by another literal --- line. Leading spaces, other delimiters and JSON or TOML front matter are not detected. A Markdown thematic rule at the start can be ambiguous; the tool treats it as an opening delimiter and requires a closing line.
Loading and exporting without editing preserves the original text, comments, BOM and line endings. YAML is not automatically formatted. Editing the YAML uses the document’s first line-ending style; the Markdown body stays exact. A final newline is added to edited metadata only when needed to keep the closing delimiter on its own line.
Use a mapping with string field names and plain strings, booleans, finite numbers, nulls, arrays and nested mappings. Empty metadata is allowed. Duplicate keys, aliases, anchors, explicit tags, directives, unsafe integers and non-finite numbers are rejected. Limits: 100,000 characters, 400 KiB, 32 collection levels and 5,000 collection or scalar values.