Paste YAML to validate it or convert it to JSON — everything runs locally in your browser and nothing is uploaded.
Frequently asked questions
What YAML features are supported?
The common subset: nested maps and lists, scalars (strings, numbers, booleans, null), quoted keys, comments, and inline flow collections like [1, 2] and {a: b}. Anchors, aliases and multi-document streams aren't parsed by this lightweight converter.
Is my data uploaded?
No. Parsing and conversion run entirely in your browser with JavaScript. Your YAML or JSON never leaves the page.
Why did my YAML fail to parse?
YAML is indentation-sensitive — mixing tabs and spaces or misaligning a nested block is the usual cause. The tool converts tabs to spaces and reports where the structure breaks.
Can I convert JSON back to YAML?
Yes. Switch the action to 'JSON → YAML' and paste JSON; the tool emits clean, indented YAML that round-trips back to the same structure.
About this YAML tool
- Converts YAML to JSON and JSON to YAML, and validates YAML structure — all in your browser, nothing uploaded.
- It supports the common YAML you meet day to day: nested maps, lists, scalars (strings, numbers, booleans, null), quoted keys and inline
[a, b]/{k: v}collections. - Very advanced YAML features (anchors & aliases, multi-document streams, complex block-scalar folding) are outside this lightweight parser — for those, validate against your target system too.
- YAML is indentation-sensitive, so the tool reports the point where structure breaks if parsing fails.
YAML was designed to be readable by people
Early YAML specifications appeared in 2001 with an explicit focus on human-readable data serialization and configuration. Indentation became part of how structure is expressed.
Why indentation deserves respect
Unlike formats that rely mainly on braces or explicit closing tags, YAML can use indentation to show nesting. A visually small indentation mistake can therefore change structure or make a document invalid.