YAMLToolbox vs yamlchecker.com
Plain YAML? Either works. Front matter in Obsidian / Hugo / Jekyll? Only one of them understands it.
TL;DR
yamlchecker.com is a smooth, editor-style YAML validator for generic YAML. YAMLToolbox is a privacy-first, browser-only tool set with a dedicated frontmatter validator and fixer. If your YAML lives inside Markdown notes, YAMLToolbox is the only one that separates the front matter block from the body and repairs common mistakes automatically.
Feature comparison
| Feature | YAMLToolbox | yamlchecker.com |
|---|---|---|
| Generic YAML validation | Yes | Yes |
| Frontmatter-aware (--- block + Markdown body) | Yes | No |
| Auto-fix common errors | Yes | No |
| Runs 100% in the browser | Yes | No (server-side) |
| Real-time code editor UI | No (textarea-based) | Yes |
| Converter tools (JSON/CSV/XML/etc.) | 16 tools | No |
Where yamlchecker.com wins
- Editor experience. It feels like an IDE, with line numbers, syntax highlighting, and live error underlines.
- Instant feedback. Errors appear as you type, which is great for learning.
- Established. It ranks well for "yaml checker" and is a solid general-purpose choice.
Where YAMLToolbox wins
- Front matter. yamlchecker.com treats
---and Markdown body as YAML syntax errors. YAMLToolbox isolates the front matter block, ignores the body, and validates only the metadata. - Auto-fix. The Frontmatter Validator & Fixer repairs missing colon spaces, trailing whitespace, duplicate keys, and more, then shows exactly what changed.
- Privacy. Nothing is uploaded. The entire page is static HTML/JS served from Vercel's edge.
- Tool breadth. One site covers validation, formatting, minification, and 16 format converters.
Who should use which
Choose yamlchecker.com if you want a polished editor for plain YAML and do not mind pasting into a third-party service.
Choose YAMLToolbox if you edit Obsidian, Hugo, Jekyll, or Astro notes; need a privacy-first workflow; or want the broken front matter repaired, not just flagged.
Try the difference
Paste this into both tools and see what happens:
---
title: My Note
tags: [yaml, notes]
draft: false
---
# Heading
Body text that is not YAML.yamlchecker.com reports an error on the --- and the Markdown body. YAMLToolbox's frontmatter validator validates the block and ignores the body.