I Got Tired of Broken YAML Front Matter in Obsidian — So I Built a No-Upload Fixer

If you use Obsidian, Hugo, or Jekyll, you've probably seen this error:

YAML front matter parsing error: ...

It usually shows up right when you need the note most. And the worst part? The error message tells you something is wrong, but rarely where.

The three mistakes I kept making

After way too many broken notes, I noticed the same culprits:

1. Tabs instead of spaces. YAML forbids tabs for indentation. One pasted tab and the whole block fails.
2. A missing closing ---. You open front matter and forget to close it.
3. Unquoted yes / no / numbers like 007. YAML silently turns yes into true and 007 into 7. For Obsidian tags or version fields, that's a silent data change.

(There's a longer catalog of these at yamltoolbox.com/yaml-errors if you want the full list.)

Why I didn't want to paste my notes into "just any" validator

Most online YAML validators ask you to paste your content into their server. For a config file that's fine. For private Obsidian notes — reading lists, daily journals, work-in-progress — I didn't love the idea.

So I built one that runs 100% in the browser. Nothing is uploaded. You paste the note, it checks only the --- block (so the Markdown body never causes false errors), and shows the exact broken line.

👉 YAML Frontmatter Validator & Fixer

What "fix" actually does

It doesn't rewrite your note into something clever. It does the conservative stuff:

• adds the missing closing ---
• trims trailing whitespace that breaks parsing
• quotes yes / no / 007 so they stay strings
• reports every change it made, line by line

Before:

---
title: My Note
tags: a, b
draft: yes

---

After:

---
title: My Note
tags:
  - a
  - b
draft: "yes"

---

The draft field stays "yes" instead of becoming a boolean. Small thing, but it's the difference between a note that renders and one that doesn't.

Validate the rest of your YAML too

The same no-upload rule applies to the plain YAML Validator — handy right before you commit a GitHub Actions or Docker Compose file.

Why I'm writing this

Third-party write-ups get cited far more than your own site does. I'm not claiming this is the only fixer out there — but if you've lost an afternoon to a missing ---, it might save you the next one.