YAML ⇄ JSON Converter
How it works
YAML → JSON reads a deliberately bounded, practical subset of YAML:
block mappings and sequences nested by 2-space indentation (including a sequence of
mappings), inline flow collections like [a, b, c] and
{a: 1, b: 2}, quoted and unquoted scalars, and # comments.
Anchors, aliases, multi-document ---/... streams, explicit
tags like !!str, and literal/folded block scalars (| and
>) are out of scope and produce a clear error naming the feature
instead of a wrong result.
JSON → YAML serializes any JSON value as block-style YAML: objects
become nested key: blocks, arrays become - lines, and a
string is wrapped in double quotes only when left bare it would be ambiguous — it
contains : or #, has leading/trailing whitespace, or would
otherwise parse back as a keyword like true/null or a number.
Frequently asked questions
What YAML features are NOT supported?
Anchors and aliases (&name / *name), multi-document streams separated by --- or ..., explicit tag directives like !!str, and literal/folded block scalars (| and >) are all out of scope — the converter throws a clear error naming the feature instead of silently mis-parsing it. Everything else a typical config file uses — mappings, sequences, inline [a, b] / {a: 1} flow collections, quoted and unquoted scalars, comments — is supported.
Why do my YAML comments disappear when I convert to JSON?
JSON has no comment syntax at all, so there is nowhere for a # note to go once the document becomes JSON — it is stripped during parsing rather than carried through as dead text that would make the output invalid JSON.
When should I reach for this instead of a full YAML library?
This covers the shape of YAML that shows up in everyday config files: nested settings, lists, simple values. If you are working with a document that uses anchors to avoid repetition, splits into multiple --- documents, or relies on block scalars for multi-line text, a real YAML library (js-yaml, PyYAML, ...) is the right tool — this one is deliberately bounded rather than spec-complete.