Skip to content
TextArray1.41.0
100% local

Front matter editor

Split, validate and reformat the YAML front matter of a Markdown document.

Input
Output
Related tools
YAML formatterDeveloper tools
YAML ⇄ JSON converterDeveloper tools
Strip MarkdownText cleaning
i18n key diffDeveloper tools
TOML to JSON converterDeveloper tools
SQL to JSONDeveloper tools
Front matter editor
Paste a Markdown document that opens with a `---`-delimited YAML front matter block and this tool splits it from the body, checks it, and returns a cleaned-up version of both. It's built for static-site content — Jekyll and Hugo posts, Astro pages, Obsidian notes — where that metadata block drifts out of shape as a site grows: keys land in a different order on every post, dates get typed in whatever format felt natural that day, and nobody notices a duplicate key until the build breaks.
Show switches between viewing front matter and body together or isolating just one. Sort keys alphabetically, or type a comma-separated order (title, date, tags…); anything left out is appended alphabetically. Required keys fills in any missing key you name with an empty value, so a batch of posts ends up with the same shape; Remove empty keys does the reverse, dropping keys whose value is blank, an empty list or an empty object. Normalize dates rewrites recognizable dates like 15.01.2024 or 01/15/2024 to 2024-01-15, leaving already-ISO dates alone. List style switches short scalar lists between one-item-per-line block form and a compact [a, b, c] inline form; lists holding nested objects stay block-style, since those can't be flattened.
The tool checks the block too: a key repeated at the top level is flagged and its line highlighted, and a block that opens with `---` but never closes is reported rather than silently swallowing the rest of the document as metadata. Turn on Process multiple documents to apply the same options across several Markdown files pasted one after another, each with its own front matter, separated by a blank line.
Everything runs locally in your browser; your document is never uploaded. Copy the result, download it as a .txt file, or send the output back into the input to keep adjusting it.
FAQ
What counts as front matter?
A block at the very start of the document that opens with a line containing only ---, holds YAML key-value pairs, and closes with another --- (or ...) line. Anything before the opening --- or without one isn't touched.
What happens if the front matter has a syntax error?
It's reported and left exactly as you pasted it, so you don't lose the original text while you fix it — the body is still split out normally.
How does "Required keys" decide what counts as missing?
It checks each name you list against the parsed front matter's own keys, case-sensitively, and adds only the ones that aren't already present, each with an empty value.
Can it edit multiple blog posts at once?
Yes — turn on "Process multiple documents" and paste several Markdown files back to back, each starting its own front matter block on a new line after a blank line. Every document gets the same options applied and the results are rejoined.
Is my document uploaded anywhere?
No. Front matter parsing and formatting run entirely in your browser — the document never leaves your device.