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: Tabs instead of spaces. YAML forbids tabs for indentation. One pasted tab and the whole block fails. A missing closing ---. You open front matter and forget to close it. 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 --- Enter fullscreen mode Exit fullscreen mode After: --- title: My Note tags: - a - b draft: "yes" --- Enter fullscreen mode Exit fullscreen mode 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.