YAML to JSON

What it does

This converter handles block mappings and sequences, flow {} and [], and comments. It does not expand anchors or aliases, apply merge keys, or keep tags. If the document uses one of those, you get an error at the line and column where it appeared.

Parse the YAML and emit JSON when the document stays inside the supported subset. If an anchor, alias, merge key or tag is present, return an error that names the feature and the line and column, and do not emit JSON.

Why it works this way

JSON has no anchors, aliases, merge keys or tags. Expanding or dropping them quietly would invent or lose a value, so this tool refuses the document and points at the first unsupported token.

Ordinary mappings, lists and scalars convert directly. That is the subset this page is for: a settings file or a list of records that does not use YAML's reference machinery.

A position in the error is what makes the refusal usable. An error that only says 'unsupported' leaves you searching the file; line and column tell you which token to remove or rewrite.

Examples

title: hello
count: 3

{
  "title": "hello",
  "count": 3
}

a: &x 1
b: *x

error at line 1 column 4: anchors and aliases are not supported

Inputs and outputs

• YAML text

• JSON text
• or an error naming the unsupported feature, with line and column

Edge cases

• multiple documents in one file
• anchors, aliases, merge keys and tags — refused, with the position of the first one
• tabs in indentation — an error in YAML
• duplicate keys

Sources

• YAML 1.2 specification, sections 3.2.2 and 6.9 (Anchors, Aliases, Tags)