YAML Tools

All-in-one YAML toolbox: validate syntax, format/beautify, explore structure with tree view, and convert to JSON. Also: YAML Compare | JSON ↔ YAML | JSON Compare.
All processing happens locally in your browser — your data is never uploaded to any server.
Mode:
Input YAML
Validation Result
How to use: Paste your YAML in the left textarea, choose a mode, and click Process.
Validate: Checks YAML syntax and reports errors with line and column numbers. Catches indentation issues, invalid mappings, and malformed sequences.
Format: Beautifies YAML with configurable indentation (2/4 spaces or tabs). Optionally sorts keys alphabetically.
Tree View: Displays the parsed YAML as an interactive collapsible tree for exploring document structure. Use the search box to filter nodes by key or value.
To JSON: Converts YAML to equivalent JSON. Complex YAML features (anchors, aliases, tags) are resolved into plain JSON objects.
What is YAML?

YAML is a configuration format built on indentation instead of brackets: nesting is whitespace, a dash starts a list item, and key: value is a mapping. Unquoted scalars get types — yes is a boolean, 07 is a number — which is why the “Norway problem” (NO = Norway, parsed as false) is famous. Anchors (&x) and aliases (*x) reuse nodes inside one document.

Anchors and aliases are resolved when converting to JSON.